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Nolde JM, Marisol Lugo‐Gavidia L, Carnagarin R, Azzam O, Galindo Kiuchi M, Mian A, Schlaich MP. Machine learning powered tools for automated analysis of muscle sympathetic nerve activity recordings. Physiol Rep 2021; 9:e14996. [PMID: 34427381 PMCID: PMC8383713 DOI: 10.14814/phy2.14996] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 07/07/2021] [Accepted: 07/10/2021] [Indexed: 01/04/2023] Open
Abstract
Automated analysis and quantification of physiological signals in clinical practice and medical research can reduce manual labor, increase efficiency, and provide more objective, reproducible results. To build a novel platform for the analysis of muscle sympathetic nerve activity (MSNA), we employed state-of-the-art data processing and machine learning applications. Data processing methods for integrated MSNA recordings were developed to evaluate signals regarding the overall quality of the signal, the validity of individual signal peaks regarding the potential to be MSNA bursts and the timing of their occurrence. An overall probability score was derived from this flexible platform to evaluate each individual signal peak automatically. Overall, three deep neural networks were designed and trained to validate individual signal peaks randomly sampled from recordings representing only electrical noise and valid microneurography recordings. A novel data processing method for the whole signal was developed to differentiate between periods of valid MSNA signal recordings and periods in which the signal was not available or lost due to involuntary movement of the recording electrode. A probabilistic model for timing of the signal bursts was implemented as part of the system. Machine Learning algorithms and data processing tools were implemented to replicate the complex decision-making process of manual MSNA analysis. Validation of manual MSNA analysis including intra- and inter-rater validity and a comparison with automated MSNA tools is required. The developed toolbox for automated MSNA analysis can be extended in a flexible way to include algorithms based on other datasets.
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Affiliation(s)
- Janis M. Nolde
- Dobney Hypertension CentreSchool of Medicine ‐ Royal Perth Hospital Research FoundationFaculty of MedicineDentistry & Health SciencesThe University of Western AustraliaPerthAustralia
| | - Leslie Marisol Lugo‐Gavidia
- Dobney Hypertension CentreSchool of Medicine ‐ Royal Perth Hospital Research FoundationFaculty of MedicineDentistry & Health SciencesThe University of Western AustraliaPerthAustralia
| | - Revathy Carnagarin
- Dobney Hypertension CentreSchool of Medicine ‐ Royal Perth Hospital Research FoundationFaculty of MedicineDentistry & Health SciencesThe University of Western AustraliaPerthAustralia
| | - Omar Azzam
- Dobney Hypertension CentreSchool of Medicine ‐ Royal Perth Hospital Research FoundationFaculty of MedicineDentistry & Health SciencesThe University of Western AustraliaPerthAustralia
| | - Márcio Galindo Kiuchi
- Dobney Hypertension CentreSchool of Medicine ‐ Royal Perth Hospital Research FoundationFaculty of MedicineDentistry & Health SciencesThe University of Western AustraliaPerthAustralia
| | - Ajmal Mian
- School of Computer Science and Software EngineeringThe University of Western AustraliaPerthAustralia
| | - Markus P. Schlaich
- Dobney Hypertension CentreSchool of Medicine ‐ Royal Perth Hospital Research FoundationFaculty of MedicineDentistry & Health SciencesThe University of Western AustraliaPerthAustralia
- Departments of Cardiology and NephrologyRoyal Perth HospitalPerthAustralia
- Neurovascular Hypertension & Kidney Disease LaboratoryBaker Heart and Diabetes InstituteMelbourneAustralia
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Reyes LM, Khurana R, Usselman CW, Busch SA, Skow RJ, Boulé NG, Davenport MH, Steinback CD. Sympathetic nervous system activity and reactivity in women with gestational diabetes mellitus. Physiol Rep 2020; 8:e14504. [PMID: 32633077 PMCID: PMC7338594 DOI: 10.14814/phy2.14504] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
INTRODUCTION Gestational diabetes mellitus (GDM) is associated with vascular dysfunction. Sympathetic nervous system activity (SNA) is an important regulator of vascular function, and is influenced by glucose and insulin. The association between GDM and SNA (re)activity is unknown. We hypothesize that women with GDM would have increased SNA during baseline and during stress. METHODS Eighteen women with GDM and 18 normoglycemic pregnant women (controls) were recruited. Muscle SNA (MSNA; peroneal microneurography) was assessed at rest, during a cold pressor test (CPT) and during peripheral chemoreflex deactivation (hyperoxia). Spontaneous sympathetic baroreflex gain was quantified versus diastolic pressure at rest and during hyperoxia. RESULTS Age, gestational age (third trimester) and pre-pregnancy body mass index and baseline MSNA was not different among the groups. Women with GDM had a similar increase in MSNA, but a greater pressor response to CPT compared to controls (% change in MAP 17 ± 7% vs. 9 ± 9%; p = .004). These data are consistent with a greater neurovascular transduction in GDM (% change in total peripheral resistance/% change in burst frequency [BF]: 15.9 ± 30.2 vs. -5.2 ± 16.4, p = .03). Interestingly, women with GDM had a greater reduction in MSNA during hyperoxia (% change in BF -30 ± 19% vs. -6 ± 17%; p = .01). CONCLUSION Women diagnosed with GDM have similar basal SNA versus normoglycemic pregnant women, but greater neurovascular transduction, meaning a greater influence of the sympathetic nerve activity in these women. We also document evidence of chemoreceptor hyperactivity, which may influence SNA in women with GDM but not in controls.
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Affiliation(s)
- Laura M. Reyes
- Program for Pregnancy and Postpartum HealthUniversity of AlbertaEdmontonABCanada
- Faculty of Kinesiology, Sport, and RecreationUniversity of AlbertaEdmontonABCanada
- Women and Children's Health Research Institute (WCHRI)University of AlbertaEdmontonABCanada
| | - Rshmi Khurana
- Women and Children's Health Research Institute (WCHRI)University of AlbertaEdmontonABCanada
- Departments of Medicine and Obstetrics and GynecologyFaculty of Medicine & DentistryUniversity of AlbertaEdmontonABCanada
| | - Charlotte W. Usselman
- Program for Pregnancy and Postpartum HealthUniversity of AlbertaEdmontonABCanada
- Women and Children's Health Research Institute (WCHRI)University of AlbertaEdmontonABCanada
| | - Stephen A. Busch
- Program for Pregnancy and Postpartum HealthUniversity of AlbertaEdmontonABCanada
- Faculty of Kinesiology, Sport, and RecreationUniversity of AlbertaEdmontonABCanada
| | - Rachel J. Skow
- Program for Pregnancy and Postpartum HealthUniversity of AlbertaEdmontonABCanada
- Faculty of Kinesiology, Sport, and RecreationUniversity of AlbertaEdmontonABCanada
- Women and Children's Health Research Institute (WCHRI)University of AlbertaEdmontonABCanada
| | - Normand G. Boulé
- Faculty of Kinesiology, Sport, and RecreationUniversity of AlbertaEdmontonABCanada
- Alberta Diabetes InstituteUniversity of AlbertaEdmontonABCanada
| | - Margie H. Davenport
- Program for Pregnancy and Postpartum HealthUniversity of AlbertaEdmontonABCanada
- Faculty of Kinesiology, Sport, and RecreationUniversity of AlbertaEdmontonABCanada
- Women and Children's Health Research Institute (WCHRI)University of AlbertaEdmontonABCanada
- Alberta Diabetes InstituteUniversity of AlbertaEdmontonABCanada
| | - Craig D. Steinback
- Program for Pregnancy and Postpartum HealthUniversity of AlbertaEdmontonABCanada
- Faculty of Kinesiology, Sport, and RecreationUniversity of AlbertaEdmontonABCanada
- Women and Children's Health Research Institute (WCHRI)University of AlbertaEdmontonABCanada
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Babcock MC, Robinson AT, Migdal KU, Watso JC, Wenner MM, Stocker SD, Farquhar WB. Reducing Dietary Sodium to 1000 mg per Day Reduces Neurovascular Transduction Without Stimulating Sympathetic Outflow. Hypertension 2019; 73:587-593. [PMID: 30661474 PMCID: PMC6374182 DOI: 10.1161/hypertensionaha.118.12074] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The American Heart Association recommends no more than 1500 mg of sodium/day as ideal. Some cohort studies suggest low-sodium intake is associated with increased cardiovascular mortality. Extremely low-sodium diets (≤500 mg/d) elicit activation of the renin-angiotensin-aldosterone system and stimulate sympathetic outflow. The effects of an American Heart Association-recommended diet on sympathetic regulation of the vasculature are unclear. Therefore, we assessed whether a 1000 mg/d diet alters sympathetic outflow and sympathetic vascular transduction compared with the more commonly recommended 2300 mg/d. We hypothesized that sodium reduction from 2300 to 1000 mg/d would not affect resting sympathetic outflow but would reduce sympathetic transduction in healthy young adults. Seventeen participants (age: 26±2 years, 9F/8M) completed 10-day 2300 and 1000 mg/d sodium diets in this randomized controlled feeding study (crossover). We measured resting renin activity, angiotensin II, aldosterone, blood pressure, muscle sympathetic nerve activity, and norepinephrine. We quantified beat-by-beat changes in mean arterial pressure and leg vascular conductance (femoral artery ultrasound) following spontaneous sympathetic bursts to assess sympathetic vascular transduction. Reducing sodium to 1000 mg/d increased renin activity, angiotensin II, and aldosterone ( P<0.01 for all) but did not alter mean arterial pressure (78±2 versus 77±2 mm Hg, P=0.56), muscle sympathetic nerve activity (13.9±1.3 versus 13.9±0.8 bursts/min, P=0.98), or plasma/urine norepinephrine. Sympathetic vascular transduction decreased ( P<0.01). These data suggest that reducing sodium from 2300 to 1000 mg/d stimulates the renin-angiotensin-aldosterone system, does not increase resting basal sympathetic outflow, and reduces sympathetic vascular transduction in normotensive adults.
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Affiliation(s)
- Matthew C. Babcock
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE 19713
| | - Austin T. Robinson
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE 19713
| | - Kamila U. Migdal
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE 19713
| | - Joseph C. Watso
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE 19713
| | - Megan M. Wenner
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE 19713
| | - Sean D. Stocker
- Department of Medicine, Division of Renal-Electrolyte, University of Pittsburgh, Pittsburgh, PA 15261
| | - William B. Farquhar
- Department of Kinesiology and Applied Physiology, University of Delaware, Newark, DE 19713
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Iordanova B, Vazquez A, Kozai TDY, Fukuda M, Kim SG. Optogenetic investigation of the variable neurovascular coupling along the interhemispheric circuits. J Cereb Blood Flow Metab 2018; 38:627-640. [PMID: 29372655 PMCID: PMC5888863 DOI: 10.1177/0271678x18755225] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 01/03/2018] [Indexed: 12/13/2022]
Abstract
The interhemispheric circuit connecting the left and the right mammalian brain plays a key role in integration of signals from the left and the right side of the body. The information transfer is carried out by modulation of simultaneous excitation and inhibition. Hemodynamic studies of this circuit are inconsistent since little is known about neurovascular coupling of mixed excitatory and inhibitory signals. We investigated the variability in hemodynamic responses driven by the interhemispheric circuit during optogenetic and somatosensory activation. We observed differences in the neurovascular response based on the stimulation site - cell bodies versus distal projections. In half of the experiments, optogenetic stimulation of the cell bodies evoked a predominant post-synaptic inhibition in the other hemisphere, accompanied by metabolic oxygen consumption without coupled functional hyperemia. When the same transcallosal stimulation resulted in predominant post-synaptic excitation, the hemodynamic response was biphasic, consisting of metabolic dip followed by functional hyperemia. Optogenetic suppression of the postsynaptic excitation abolished the coupled functional hyperemia. In contrast, light stimulation at distal projections evoked consistently a metabolic response. Our findings suggest that functional hyperemia requires signals originating from the cell body and the hemodynamic response variability appears to reflect the balance between the post-synaptic excitation and inhibition.
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Affiliation(s)
- Bistra Iordanova
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Alberto Vazquez
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Takashi DY Kozai
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Mitsuhiro Fukuda
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Seong-Gi Kim
- Center for Neuroscience Imaging Research, Institute for Basic Science, Suwon, Korea
- Department of Biomedical Engineering, Sungkyunkwan University, Suwon, Korea
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Nyberg M, Piil P, Kiehn OT, Maagaard C, Jørgensen TS, Egelund J, Isakson BE, Nielsen MS, Gliemann L, Hellsten Y. Probenecid Inhibits α-Adrenergic Receptor-Mediated Vasoconstriction in the Human Leg Vasculature. Hypertension 2018; 71:151-159. [PMID: 29084879 PMCID: PMC5876717 DOI: 10.1161/hypertensionaha.117.10251] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2017] [Revised: 09/11/2017] [Accepted: 10/09/2017] [Indexed: 01/07/2023]
Abstract
Coordination of vascular smooth muscle cell tone in resistance arteries plays an essential role in the regulation of peripheral resistance and overall blood pressure. Recent observations in animals have provided evidence for a coupling between adrenoceptors and Panx1 (pannexin-1) channels in the regulation of sympathetic nervous control of peripheral vascular resistance and blood pressure; however, evidence for a functional coupling in humans is lacking. We determined Panx1 expression and effects of treatment with the pharmacological Panx1 channel inhibitor probenecid on the vasoconstrictor response to α1- and α2-adrenergic receptor stimulation in the human forearm and leg vasculature of young healthy male subjects (23±3 years). By use of immunolabeling and confocal microscopy, Panx1 channels were found to be expressed in vascular smooth muscle cells of arterioles in human leg skeletal muscle. Probenecid treatment increased (P<0.05) leg vascular conductance at baseline by ≈15% and attenuated (P<0.05) the leg vasoconstrictor response to arterial infusion of tyramine (α1- and α2-adrenergic receptor stimulation) by ≈15%, whereas the response to the α1-agonist phenylephrine was unchanged. Inhibition of α1-adrenoceptors prevented the probenecid-induced increase in baseline leg vascular conductance, but did not alter the effect of probenecid on the vascular response to tyramine. No differences with probenecid treatment were detected in the forearm. These observations provide the first line of evidence in humans for a functional role of Panx1 channels in setting resting tone via α1-adrenoceptors and in the constrictive effect of noradrenaline via α2-adrenoceptors, thereby contributing to the regulation of peripheral vascular resistance and blood pressure in humans.
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Affiliation(s)
- Michael Nyberg
- From the Department of Nutrition, Exercise and Sports (M.N., P.P., O.T.K., C.M., T.S.J., J.E., L.G., Y.H.) and Department of Biomedical Sciences, Faculty of Health and Medical Sciences (M.S.N.), University of Copenhagen, Denmark; Department of Orthopedics, Herlev and Gentofte Hospital, Hellerup, Denmark (T.S.J.); and Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville (B.E.I.)
| | - Peter Piil
- From the Department of Nutrition, Exercise and Sports (M.N., P.P., O.T.K., C.M., T.S.J., J.E., L.G., Y.H.) and Department of Biomedical Sciences, Faculty of Health and Medical Sciences (M.S.N.), University of Copenhagen, Denmark; Department of Orthopedics, Herlev and Gentofte Hospital, Hellerup, Denmark (T.S.J.); and Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville (B.E.I.)
| | - Oliver T Kiehn
- From the Department of Nutrition, Exercise and Sports (M.N., P.P., O.T.K., C.M., T.S.J., J.E., L.G., Y.H.) and Department of Biomedical Sciences, Faculty of Health and Medical Sciences (M.S.N.), University of Copenhagen, Denmark; Department of Orthopedics, Herlev and Gentofte Hospital, Hellerup, Denmark (T.S.J.); and Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville (B.E.I.)
| | - Christian Maagaard
- From the Department of Nutrition, Exercise and Sports (M.N., P.P., O.T.K., C.M., T.S.J., J.E., L.G., Y.H.) and Department of Biomedical Sciences, Faculty of Health and Medical Sciences (M.S.N.), University of Copenhagen, Denmark; Department of Orthopedics, Herlev and Gentofte Hospital, Hellerup, Denmark (T.S.J.); and Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville (B.E.I.)
| | - Tue S Jørgensen
- From the Department of Nutrition, Exercise and Sports (M.N., P.P., O.T.K., C.M., T.S.J., J.E., L.G., Y.H.) and Department of Biomedical Sciences, Faculty of Health and Medical Sciences (M.S.N.), University of Copenhagen, Denmark; Department of Orthopedics, Herlev and Gentofte Hospital, Hellerup, Denmark (T.S.J.); and Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville (B.E.I.)
| | - Jon Egelund
- From the Department of Nutrition, Exercise and Sports (M.N., P.P., O.T.K., C.M., T.S.J., J.E., L.G., Y.H.) and Department of Biomedical Sciences, Faculty of Health and Medical Sciences (M.S.N.), University of Copenhagen, Denmark; Department of Orthopedics, Herlev and Gentofte Hospital, Hellerup, Denmark (T.S.J.); and Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville (B.E.I.)
| | - Brant E Isakson
- From the Department of Nutrition, Exercise and Sports (M.N., P.P., O.T.K., C.M., T.S.J., J.E., L.G., Y.H.) and Department of Biomedical Sciences, Faculty of Health and Medical Sciences (M.S.N.), University of Copenhagen, Denmark; Department of Orthopedics, Herlev and Gentofte Hospital, Hellerup, Denmark (T.S.J.); and Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville (B.E.I.)
| | - Morten S Nielsen
- From the Department of Nutrition, Exercise and Sports (M.N., P.P., O.T.K., C.M., T.S.J., J.E., L.G., Y.H.) and Department of Biomedical Sciences, Faculty of Health and Medical Sciences (M.S.N.), University of Copenhagen, Denmark; Department of Orthopedics, Herlev and Gentofte Hospital, Hellerup, Denmark (T.S.J.); and Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville (B.E.I.)
| | - Lasse Gliemann
- From the Department of Nutrition, Exercise and Sports (M.N., P.P., O.T.K., C.M., T.S.J., J.E., L.G., Y.H.) and Department of Biomedical Sciences, Faculty of Health and Medical Sciences (M.S.N.), University of Copenhagen, Denmark; Department of Orthopedics, Herlev and Gentofte Hospital, Hellerup, Denmark (T.S.J.); and Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville (B.E.I.)
| | - Ylva Hellsten
- From the Department of Nutrition, Exercise and Sports (M.N., P.P., O.T.K., C.M., T.S.J., J.E., L.G., Y.H.) and Department of Biomedical Sciences, Faculty of Health and Medical Sciences (M.S.N.), University of Copenhagen, Denmark; Department of Orthopedics, Herlev and Gentofte Hospital, Hellerup, Denmark (T.S.J.); and Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville (B.E.I.).
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Del Pozzi AT, Miller JT, Hodges GJ. The effect of heating rate on the cutaneous vasomotion responses of forearm and leg skin in humans. Microvasc Res 2016; 105:77-84. [PMID: 26808211 DOI: 10.1016/j.mvr.2016.01.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 01/19/2016] [Accepted: 01/20/2016] [Indexed: 11/19/2022]
Abstract
We examined skin blood flow (SkBF) and vasomotion in the forearm and leg using laser-Doppler fluxmetry (LDF) and spectral analysis to investigate endothelial, sympathetic, and myogenic activities in response to slow (0.1 °C·10 s(-1)) and fast (0.5 °C·10 s(-1)) local heating. At 33 °C (thermoneutral) endothelial activity was higher in the legs than the forearms (P ≤ 0.02). Fast-heating increased SkBF more than slow heating (P=0.037 forearm; P=0.002 leg). At onset of 42 °C, endothelial (P=0.043 forearm; P=0.48 leg) activity increased in both regions during the fast-heating protocol. Following prolonged heating (42 °C) endothelial activity was higher in both the forearm (P=0.002) and leg (P<0.001) following fast-heating. These results confirm regional differences in the response to local heating and suggest that the greater increase in SkBF in response to fast local heating is initially due to increased endothelial and sympathetic activity. Furthermore, with sustained local skin heating, greater vasodilatation was observed with fast heating compared to slow heating. These data indicate that this difference is due to greater endothelial activity following fast heating compared to slow heating, suggesting that the rate of skin heating may alter the mechanisms contributing to cutaneous vasodilatation.
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Affiliation(s)
- Andrew T Del Pozzi
- Integrative Exercise Physiology Laboratory, School of Kinesiology, Ball State University, Muncie, IN 47306, United States
| | - James T Miller
- Exercise Physiology Laboratory, Department of Kinesiology, The University of Alabama, Tuscaloosa, AL 35487, United States
| | - Gary J Hodges
- Environmental Ergonomics Laboratory, Department of Kinesiology, Brock University, St. Catharines, ON L2S 3A1, Canada.
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Abstract
Fetal hypoxia triggers compensatory angiogenesis and remodeling through mechanisms not fully elucidated. In response to hypoxia, hypoxia-inducible factor drives expression of cytokines that exert multiple effects on cerebral structures. Among these, the artery wall is composed of a heterogeneous cell mix and exhibits distinct patterns of cellular differentiation and reactivity. Governing these patterns are the vascular endothelium, smooth muscle (SM), adventitia, sympathetic perivascular nerves (SPN), and the parenchyma. Although an extensive literature details effects of nonneuronal factors on cerebral arteries, the trophic role of perivascular nerves remains unclear. Hypoxia increases sympathetic innervation with subsequent release of norepinephrine (NE), neuropeptide-Y (NPY), and adenosine triphosphate, which exert motor and trophic effects on cerebral arteries and influence dynamic transitions among SM phenotypes. Our data also suggest that the cerebrovasculature reacts very differently to hypoxia in fetuses and adults, and we hypothesize that these differences arise from age-related differences in arterial SM phenotype reactivity and proximity to trophic factors, particularly of neural origin. We provide an integration of recent literature focused on mechanisms by which SPN mediate hypoxic remodeling. Our recent findings suggest that trophic effects of SPN on cerebral arteries accelerate functional maturation through shifts in SM phenotype in an age-dependent manner.
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MESH Headings
- Adenosine Triphosphate/metabolism
- Adult
- Age Factors
- Animals
- Cerebrovascular Circulation
- Fetal Hypoxia/complications
- Fetal Hypoxia/metabolism
- Fetal Hypoxia/physiopathology
- Humans
- Hypoxia, Brain/complications
- Hypoxia, Brain/metabolism
- Hypoxia, Brain/physiopathology
- Muscle, Smooth, Vascular/innervation
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/pathology
- Muscle, Smooth, Vascular/physiopathology
- Neovascularization, Pathologic/etiology
- Neovascularization, Pathologic/metabolism
- Neovascularization, Pathologic/physiopathology
- Neuropeptide Y/metabolism
- Norepinephrine/metabolism
- Sympathetic Nervous System/metabolism
- Sympathetic Nervous System/physiopathology
- Vascular Remodeling
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Affiliation(s)
- Olayemi O Adeoye
- Divisions of Physiology, Pharmacology, and Biochemistry, Center for Perinatal Biology, Loma Linda University School of Medicine, Loma Linda, CA
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Boleeva GS, Mochalov SV, Tarasova OS. [Functional alterations of the arterial vessels in experimental models of type 1 diabetes mellitus]. Usp Fiziol Nauk 2014; 45:20-36. [PMID: 25707261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The review analyzws the literature on the pathological alterations of endothelium, smooth muscle and vasomotor innervation of arterial vessels in animal modes of type 1 diabetes mellitus. Particular attention is paid t the analysis of mechanisms of diabetic abnormalities in the light of modern knowledge on the functioning of the main components of the vascular wall.
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MESH Headings
- Alloxan/pharmacology
- Animals
- Arteries/innervation
- Arteries/physiopathology
- Biological Factors/metabolism
- Diabetes Mellitus, Experimental/chemically induced
- Diabetes Mellitus, Experimental/physiopathology
- Diabetes Mellitus, Type 1/chemically induced
- Diabetes Mellitus, Type 1/physiopathology
- Endothelins/metabolism
- Endothelium, Vascular/innervation
- Endothelium, Vascular/metabolism
- Endothelium, Vascular/physiopathology
- Humans
- Muscle Contraction/physiology
- Muscle, Smooth, Vascular/innervation
- Muscle, Smooth, Vascular/physiopathology
- Streptozocin/pharmacology
- Vasomotor System/physiology
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Sun PC, Kuo CD, Chi LY, Lin HD, Wei SH, Chen CS. Microcirculatory vasomotor changes are associated with severity of peripheral neuropathy in patients with type 2 diabetes. Diab Vasc Dis Res 2013; 10:270-6. [PMID: 23241514 DOI: 10.1177/1479164112465443] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Systemic microvascular complications are related to the presence of diabetic neuropathy. This study investigated the associations of blood flow oscillations with peripheral neuropathy in 25 controls and 3 diabetic groups including clinical (24), subclinical (27) and without neuropathy (26). Laser Doppler skin perfusion was transformed into three low-frequency subintervals corresponding to endothelial, neurogenic and myogenic vasomotor controls. The average vasomotion was significantly reduced in clinical neuropathy group and characterized by endothelial and neural but not smooth muscle-related changes. The normalized spectrums revealed a relative increase of myogenic and decrease of neurogenic activity in subclinical neuropathy group. The myogenic component showed a statistically inverse correlation with postural fall in systolic blood pressure (r = -0.32, p < 0.01). The diabetic patients with decreased low-frequency vasomotor responses were associated with increased odds ratio of peripheral neuropathy [odds ratio = 3.51 (95% confidence interval = 1.19-10.31), p = 0.02]. This study elucidated possible interaction between impaired microvascular flow motion and diabetic peripheral neuropathy. The vasomotor changes of skin microcirculation could be detected even in the absence of overt cardiovascular dysfunction.
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Affiliation(s)
- Pi-Chang Sun
- Division of Rehabilitation Medicine, Taipei City Hospital, Taipei, Taiwan.
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Nam J, Onitsuka I, Hatch J, Uchida Y, Ray S, Huang S, Li W, Zang H, Ruiz-Lozano P, Mukouyama YS. Coronary veins determine the pattern of sympathetic innervation in the developing heart. Development 2013; 140:1475-85. [PMID: 23462468 PMCID: PMC3596991 DOI: 10.1242/dev.087601] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Anatomical congruence of peripheral nerves and blood vessels is well recognized in a variety of tissues. Their physical proximity and similar branching patterns suggest that the development of these networks might be a coordinated process. Here we show that large diameter coronary veins serve as an intermediate template for distal sympathetic axon extension in the subepicardial layer of the dorsal ventricular wall of the developing mouse heart. Vascular smooth muscle cells (VSMCs) associate with large diameter veins during angiogenesis. In vivo and in vitro experiments demonstrate that these cells mediate extension of sympathetic axons via nerve growth factor (NGF). This association enables topological targeting of axons to final targets such as large diameter coronary arteries in the deeper myocardial layer. As axons extend along veins, arterial VSMCs begin to secrete NGF, which allows axons to reach target cells. We propose a sequential mechanism in which initial axon extension in the subepicardium is governed by transient NGF expression by VSMCs as they are recruited to coronary veins; subsequently, VSMCs in the myocardium begin to express NGF as they are recruited by remodeling arteries, attracting axons toward their final targets. The proposed mechanism underlies a distinct, stereotypical pattern of autonomic innervation that is adapted to the complex tissue structure and physiology of the heart.
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MESH Headings
- Animals
- Axons/physiology
- Cells, Cultured
- Chick Embryo
- Coronary Vessels/embryology
- Coronary Vessels/innervation
- Coronary Vessels/physiology
- Embryo Culture Techniques
- Embryo, Mammalian
- Heart/embryology
- Heart/innervation
- Mice
- Mice, Transgenic
- Models, Biological
- Muscle, Smooth, Vascular/embryology
- Muscle, Smooth, Vascular/innervation
- Muscle, Smooth, Vascular/metabolism
- Pericardium/embryology
- Pericardium/innervation
- Sympathetic Nervous System/embryology
- Sympathetic Nervous System/physiology
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Affiliation(s)
- Joseph Nam
- Laboratory of Stem Cell and Neuro-Vascular Biology, Genetics and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10/6C103, 10 Center Drive, Bethesda, MD 20892, USA
| | - Izumi Onitsuka
- Laboratory of Stem Cell and Neuro-Vascular Biology, Genetics and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10/6C103, 10 Center Drive, Bethesda, MD 20892, USA
| | - John Hatch
- Laboratory of Stem Cell and Neuro-Vascular Biology, Genetics and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10/6C103, 10 Center Drive, Bethesda, MD 20892, USA
| | - Yutaka Uchida
- Laboratory of Stem Cell and Neuro-Vascular Biology, Genetics and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10/6C103, 10 Center Drive, Bethesda, MD 20892, USA
| | - Saugata Ray
- Development and Aging Program, Sanford-Burnham Medical Research Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Siyi Huang
- Department of Neuroscience, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205, USA
| | - Wenling Li
- Laboratory of Stem Cell and Neuro-Vascular Biology, Genetics and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10/6C103, 10 Center Drive, Bethesda, MD 20892, USA
| | - Heesuk Zang
- Laboratory of Stem Cell and Neuro-Vascular Biology, Genetics and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10/6C103, 10 Center Drive, Bethesda, MD 20892, USA
| | - Pilar Ruiz-Lozano
- Development and Aging Program, Sanford-Burnham Medical Research Institute, 10901 North Torrey Pines Road, La Jolla, CA 92037, USA
- Pediatric Cardiology, Stanford University School of Medicine, 300 Pasteur Drive, Palo Alto, CA 94305, USA
| | - Yoh-suke Mukouyama
- Laboratory of Stem Cell and Neuro-Vascular Biology, Genetics and Developmental Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Building 10/6C103, 10 Center Drive, Bethesda, MD 20892, USA
- Author for correspondence ()
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11
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Kagitani F, Uchida S, Hotta H. The role of alpha adrenoceptors in the vascular and estradiol secretory responses to stimulation of the superior ovarian nerve. J Physiol Sci 2011; 61:247-51. [PMID: 21359965 PMCID: PMC10717463 DOI: 10.1007/s12576-011-0135-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2010] [Accepted: 02/08/2011] [Indexed: 10/18/2022]
Abstract
Electrical stimulation of the superior ovarian nerve in rats reduces both the plasma flow rate of ovarian venous blood (ovarian blood flow) and the ovarian estradiol secretion rate. Here, we examined the possible roles of alpha-adrenoceptors in these processes. The reduction of the plasma flow rate was blocked by an alpha 1- (prazosin), but not by an alpha 2- (yohimbine) adrenoceptor blocker. In contrast, the reduction of the estradiol secretion rate was blocked by yohimbine but not by prazosin. We conclude that ovarian vascular and estradiol secretory responses to superior ovarian nerve activation are mediated by alpha 1- and alpha 2-adrenoceptors, respectively.
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MESH Headings
- Adrenergic alpha-1 Receptor Antagonists/pharmacology
- Adrenergic alpha-2 Receptor Antagonists/pharmacology
- Animals
- Blood Pressure/drug effects
- Electric Stimulation/methods
- Estradiol/metabolism
- Female
- Muscle, Smooth, Vascular/blood supply
- Muscle, Smooth, Vascular/innervation
- Muscle, Smooth, Vascular/metabolism
- Ovary/blood supply
- Ovary/innervation
- Ovary/metabolism
- Ovary/physiology
- Prazosin/pharmacology
- Rats
- Rats, Wistar
- Receptors, Adrenergic, alpha-1/metabolism
- Receptors, Adrenergic, alpha-2/metabolism
- Receptors, Adrenergic, beta/metabolism
- Regional Blood Flow/drug effects
- Yohimbine/pharmacology
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Affiliation(s)
- Fusako Kagitani
- Department of Autonomic Neuroscience, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakae-cho, Itabashi-ku, Tokyo, 173-0015, Japan.
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12
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Toda N, Toda H. Nitric oxide-mediated blood flow regulation as affected by smoking and nicotine. Eur J Pharmacol 2010; 649:1-13. [PMID: 20868673 DOI: 10.1016/j.ejphar.2010.09.042] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Revised: 08/01/2010] [Accepted: 09/14/2010] [Indexed: 12/15/2022]
Abstract
Cigarette smoking is a major risk factor for atherosclerosis, cerebral and coronary vascular diseases, hypertension, and diabetes mellitus. Chronic smoking impairs endothelial function by decreasing the formation of nitric oxide and increasing the degradation of nitric oxide via generation of oxygen free radicals. Nitric oxide liberated from efferent nitrergic nerves is also involved in vasodilatation, increased regional blood flow, and hypotension that are impaired through nitric oxide sequestering by smoking-induced factors. Influence of smoking on nitric oxide-induced blood flow regulation is not necessarily the same in all organs and tissues. However, human studies are limited mainly to the forearm blood flow measurement that assesses endothelial function under basal and stimulated conditions and also determination of penile tumescence and erection in response to endothelial and neuronal nitric oxide. Therefore, information about blood flow regulation in other organs, such as the brain and placenta, has been provided mainly from studies on experimental animals. Nicotine, a major constituent of cigarette smoke, acutely dilates cerebral arteries and arterioles through nitric oxide liberated from nitrergic neurons, but chronically interferes with endothelial function in various vasculatures, both being noted in studies on experimental animals. Cigarette smoke constituents other than nicotine also have some vascular actions. Not only active but also passive smoking is undoubtedly harmful for both the smokers themselves and their neighbors, who should bear in mind that they can face serious diseases in the future, which may result in lengthy hospitalization, and a shortened lifespan.
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Affiliation(s)
- Noboru Toda
- Toyama Institute for Cardiovascular Research, 7-13, 1-Chome, Azuchi-machi, Chuo-ku, Osaka 541-0052, Japan.
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13
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Zhong XZ, Harhun MI, Olesen SP, Ohya S, Moffatt JD, Cole WC, Greenwood IA. Participation of KCNQ (Kv7) potassium channels in myogenic control of cerebral arterial diameter. J Physiol 2010; 588:3277-93. [PMID: 20624791 PMCID: PMC2976022 DOI: 10.1113/jphysiol.2010.192823] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2010] [Accepted: 07/09/2010] [Indexed: 01/11/2023] Open
Abstract
KCNQ gene expression was previously shown in various rodent blood vessels, where the products of KCNQ4 and KCNQ5, Kv7.4 and Kv7.5 potassium channel subunits, respectively, have an influence on vascular reactivity. The aim of this study was to determine if small cerebral resistance arteries of the rat express KCNQ genes and whether Kv7 channels participate in the regulation of myogenic control of diameter. Quantitative reverse transcription polymerase chain reaction (QPCR) was undertaken using RNA isolated from rat middle cerebral arteries (RMCAs) and immunocytochemistry was performed using Kv7 subunit-specific antibodies and freshly isolated RMCA myocytes. KCNQ4 message was more abundant than KCNQ5 = KCNQ1, but KCNQ2 and KCNQ3 message levels were negligible. Kv7.1, Kv7.4 and Kv7.5 immunoreactivity was present at the sarcolemma of freshly isolated RMCA myocytes. Linopirdine (1 microm) partially depressed, whereas the Kv7 activator S-1 (3 and/or 20 microm) enhanced whole-cell Kv7.4 (in HEK 293 cells), as well as native RMCA myocyte Kv current amplitude. The effects of S-1 were voltage-dependent, with progressive loss of stimulation at potentials of >15 mV. At the concentrations employed linopirdine and S-1 did not alter currents due to recombinant Kv1.2/Kv1.5 or Kv2.1/Kv9.3 channels (in HEK 293 cells) that are also expressed by RMCA myocytes. In contrast, another widely used Kv7 blocker, XE991 (10 microm), significantly attenuated native Kv current and also reduced Kv1.2/Kv1.5 and Kv2.1/Kv9.3 currents. Pressurized arterial myography was performed using RMCAs exposed to intravascular pressures of 10-100 mmHg. Linopirdine (1 microm) enhanced the myogenic response at 20 mmHg, whereas the activation of Kv7 channels with S-1 (20 microm) inhibited myogenic constriction at >20 mmHg and reversed the increased myogenic response produced by suppression of Kv2-containing channels with 30 nm stromatoxin (ScTx1). These data reveal a novel contribution of KCNQ gene products to the regulation of myogenic control of cerebral arterial diameter and suggest that Kv7 channel activating drugs may be appropriate candidates for the development of an effective therapy to ameliorate cerebral vasospasm.
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Affiliation(s)
- Xi Zoë Zhong
- Ion Channels and Cell Signaling Centre, Division of Basic Medical Sciences, St George's University of London, London SW17 0RE, UK
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14
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Zeveke AV, Shabanov DV. [A study of skin deformation by optical coherent microscopy]. Biofizika 2010; 55:356-360. [PMID: 20429293] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The deformation of rat skin in response to cooling and stimulation of nerve fibers innervating the muscles piloerectors and vasoconstrictors has been studied by optical coherent microscopy. It has been found that the deformation of the skin on cooling occurs due to the contraction of bundles of collagen fibers rather than smooth muscles of vessels and piloerectors.
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15
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Abstract
After defining truly "neurotrophic" influences, and giving examples from the many studies of such influences on the somatomotor system, current research concerning sympathetic neurotrophic effects on the vascular bed is discussed. Tissue-culture studies have made it clear that, particularly in early growth phases, local trophic influences are quite important and interdependent between adrenergic neurons and vascular smooth muscle cells. Most experiments aimed at illustrating neurotrophic effects on vascular beds in vivo, however, seem to suggest the dominance of long-term adaptation processes inherent in the effector cells themselves which, particularly on sustained extrinsic activation however achieved, become increasingly mobilised. This is not to dispute the fact that truly neurotrophic influences seem to be superimposed, facilitating and modulating these essentially intrinsic mechanisms for long-term effector cell adaptation, but their relative importance is difficult to judge.
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16
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Tarasova OS, Kalenchuk VU, Borzykh AA, Andreev-Andrievskiĭ AA, Buravkov SV, Sharova AP, Vinogradova OL. [Comparative analysis of vasomotor responses and sympathetic innervation of feed arteries from locomotor and respiratory muscles in a rat]. Biofizika 2008; 53:1095-1101. [PMID: 19137698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The characteristics of feeding arteries of diaphragm and medial gastrocnemius (with a diameter of 200-250 micron) were studied. The registration of the mechanical activity of ring preparations under isometric conditions revealed that diaphragm arteries, like arteries of other muscles with a high content of slow muscle fibers, are highly sensitive to adrenoceptor agonists and acetylcholine. The differences in endothelium-dependent relaxation between diaphragm and gastrocnemius arteries are preserved in the presence of L-NAME and diclofenac. Responses to serotonin in diaphragm and gastrocnemius arteries are similar. At the same time, the high density of innervation is characteristic of diaphragm artery only, while in other slow muscles it is low. The density of adrenergic fibers plexus in the diaphragm artery is much higher than in the gastrocnemius artery. The results suggest that the properties of small arteries of diaphragm are determined not only by the oxidative capacity of diaphragm muscle fibers but also by the belonging of the diaphragm to respiratory musculature.
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17
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Mochalov SV, Kalenchuk VU, Gaĭnullina DK, Vorotnikov AV, Tarasova OS. [The contribution of protein kinase C and Rho-kinase to the control of the receptor-dependent artery contraction decreases with age independently of sympathetic innervation]. Biofizika 2008; 53:1102-1108. [PMID: 19137699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The age-related dynamics of the activity of signalling pathways coupled to alpha1-adrenergic receptors and their dependence on the sympathetic innervation of arterial smooth muscle have been studied. The effects of the protein kinase C inhibitor (GF109203X, 10(-6) M) and the Rho-kinase inhibitor (Y27632, 10(-5) M) on the isometric contraction of the rat saphenous artery, induced by the alpha1-adrenoceptor agonist methoxamine, were examined. It was shown that the sensitivity to methoxamine of arteries from 2-week-old rats that are partially innervated was reduced as compared to adults, but the effects of both inhibitors were more prominent. The denervation induced by the excision of sympathetic ganglia increased the arterial sensitivity to methoxamine but was not accompanied by changes in sensitivity to the inhibitors. Therefore, the postnatal development of the arterial smooth muscle is characterized by a decrease in the contribution of protein kinase C and Rho-kinase to the regulation of contraction; however, these changes do not correlate with changes in the sensitivity of arteries to methoxamine and development of sympathetic innervation.
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MESH Headings
- Adrenergic alpha-1 Receptor Agonists
- Age Factors
- Amides/pharmacology
- Animals
- Arteries/growth & development
- Arteries/innervation
- Arteries/physiology
- Ganglionectomy
- Indoles/pharmacology
- Isometric Contraction
- Maleimides/pharmacology
- Methoxamine/pharmacology
- Muscle, Skeletal/blood supply
- Muscle, Smooth, Vascular/growth & development
- Muscle, Smooth, Vascular/innervation
- Muscle, Smooth, Vascular/physiology
- Protein Kinase C/antagonists & inhibitors
- Protein Kinase C/physiology
- Pyridines/pharmacology
- Rats
- Rats, Wistar
- Receptors, Adrenergic, alpha-1/physiology
- Sympathetic Nervous System/growth & development
- Sympathetic Nervous System/physiology
- rho-Associated Kinases/antagonists & inhibitors
- rho-Associated Kinases/physiology
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18
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Ma HJ, Cao YK, Liu YX, Wang R, Wu YM. Microinjection of resveratrol into rostral ventrolateral medulla decreases sympathetic vasomotor tone through nitric oxide and intracellular Ca2+ in anesthetized male rats. Acta Pharmacol Sin 2008; 29:906-12. [PMID: 18664323 DOI: 10.1111/j.1745-7254.2008.00827.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
AIM To define the effect of resveratrol (RES) on the central regulation of blood pressure (BP), heart rate (HR), and renal sympathetic nerve activity (RSNA). METHODS RES was microinjected into the rostral ventrolateral medulla (RVLM), and BP, HR, and RSNA were recorded simultaneously in anesthetized rats. RESULTS A microinjection of RES (20, 40, and 80 micromol/L, 0.2 microL) into the RVLM dose dependently decreased BP, HR, and RSNA. Pretreatment with an anti-estrogen tamoxifen (100 micromol/L, 0.2 microL) did not affect the effects of RES. Pretreatment with NG-nitro- L-arginine methyl ester (100 micromol/L, 0.2 microL), an inhibitor of nitric oxide (NO) synthase, could completely abolish the effect of RES. A prior microinjection of Bay K8644 (500 nmol/L, 0.2 microL), an agonist of calcium channels, could also abrogate the effect of RES. Prior administration of a potent inhibitor of tyrosine phosphatase, sodium orthovanadate (1 mmol/L, 0.2 microL), could partially attenuate the inhibitory effect of RES. CONCLUSION The results suggest that a microinjection of RES into the RVLM inhibits BP, HR, and RSNA. The effects may be mediated by NO synthesis and a decrease in Ca2+ influx, in which protein tyrosine kinase is involved.
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Affiliation(s)
- Hui-juan Ma
- Department of Physiology, Hebei Medical University, Shijiazhuang 050017, China
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19
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Agadzhanian NA, Kupriianov SV. [Baroreflexes originated in vertebral artery zones upon peripheral vein tonus, systemic arterial blood pressure, and external respiration]. Ross Fiziol Zh Im I M Sechenova 2008; 94:661-669. [PMID: 18727375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The investigation was intended to study the role ofbaroreceptors ofhemodynamically isolated zone of vertebral arteries in regulation of peripheral veins tonus, arterial pressure and external respiration. Pressure decrease in this vascular reflexogenic zone led to reflex responses of increase in femoral vein tonus, elevation of blood pressure level and stimulation of external respiration. The opposite reflex responses of cardio-respiratory functional system to initial pressure activation of vertebral arteries baroreceptors are observed. Basing on generalization of our own findings and similar physiological and morphological researches of other authors, it is established that afferentation from the vertebral artery zone is a reflexogenic factor of somatic muscles' veins tonus regulation. These reflexes of capacity vessels tonic activity changes are part of cardio-respiratory responses of maintaining the tissue gaseous exchange.
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20
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Burnstock G. Dual control of vascular tone and remodelling by ATP released from nerves and endothelial cells. Pharmacol Rep 2008; 60:12-20. [PMID: 18276981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2007] [Revised: 11/18/2007] [Indexed: 05/25/2023]
Abstract
Purinergic signalling is important both in short-term control of vascular tone and in longer-term control of cell proliferation, migration and death involved in vascular remodelling. There is dual control of vascular tone by ATP released from perivascular nerves and by ATP released from endothelial cells in response to changes in blood flow (shear stress) and hypoxia. Both ATP and its breakdown product, adenosine, regulate smooth muscle and endothelial cell proliferation. The involvement of these regulatory mechanisms in pathological conditions, including hypertension, atherosclerosis, restenosis, diabetes and vascular pain, are discussed.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, Royal Free and University College Medical School, Rowland Hill Street, London, UK.
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21
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Seto V, Hirota C, Hirota S, Janssen LJ. E-Ring Isoprostanes Stimulate a Cl Conductance in Airway Epithelium via Prostaglandin E2-Selective Prostanoid Receptors. Am J Respir Cell Mol Biol 2007; 38:88-94. [PMID: 17673688 DOI: 10.1165/rcmb.2007-0117oc] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Isoprostanes comprise a class of membrane lipid metabolites produced during oxidative stress, including asthma, chronic obstructive pulmonary disease, and cystic fibrosis. They are widely recognized to evoke a variety of biological responses in airway and pulmonary vascular smooth muscle, lymphatics, and innervation. However, their effects on airway epithelium are largely unstudied. We examined the electrophysiological responses evoked by several different isoprostane species in bovine airway epithelium using the Ussing chamber technique. The E-ring isoprostanes 15-E(1t)-IsoP and 15-E(2t)-IsoP evoked a substantial increase in short-circuit current (I(SC)), whereas four different F-ring isomers were ineffective. 15-E(2t)-IsoP-evoked I(SC) was mimicked by the prostaglandin E(2)-selective prostanoid receptor (EP)-agonist prostaglandin E(2) but not by agonists of EP(1)/EP(3)-, FP-, or TP receptors (sulprostone, fluprostenol, and U46619, respectively). This response was significantly reduced by the EP(4)-receptor blocker GW627386 but not by blockers of other prostanoid receptors (ICI 192,605 [TP-selective], SC19220 [EP(1)-selective], AH6809 [DP/EP(1)/EP(2)-selective], and AL8810 [FP-selective]). 15-E(2t)-IsoP-evoked I(SC) was reduced by blockers of Cl(-) channels (niflumic acid and 5-nitro-2-(3-phenylpropylamino)-benzoic acid), of Na(+)/K(+)/2Cl(-) co-transport (furosemide and bumetanide), of adenylate cyclase (MDL 12,330A), or of guanylate cyclase (1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one) but not by blockers of Na(+) conductances (amiloride). We conclude that 15-E(2t)-IsoP activates a transepithelial Cl(-) conductance in bovine airway epithelium through an EP(4) receptor coupled to adenylate cyclase and soluble guanylate cyclase.
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MESH Headings
- Animals
- Cattle
- Chloride Channel Agonists
- Chloride Channels/metabolism
- Electric Conductivity
- Evoked Potentials/drug effects
- Ion Transport/drug effects
- Isoprostanes/chemical synthesis
- Isoprostanes/chemistry
- Isoprostanes/pharmacology
- Membrane Lipids/metabolism
- Muscle, Smooth, Vascular/innervation
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/pathology
- Oxidative Stress/drug effects
- Pulmonary Disease, Chronic Obstructive/drug therapy
- Pulmonary Disease, Chronic Obstructive/metabolism
- Pulmonary Disease, Chronic Obstructive/pathology
- Receptors, Prostaglandin E/agonists
- Receptors, Prostaglandin E/metabolism
- Receptors, Prostaglandin E, EP4 Subtype
- Respiratory Mucosa/innervation
- Respiratory Mucosa/metabolism
- Respiratory Mucosa/pathology
- Tissue Culture Techniques
- Trachea/innervation
- Trachea/metabolism
- Trachea/pathology
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Affiliation(s)
- Victoria Seto
- Firestone Institute for Respiratory Health, St. Joseph's Healthcare, and Department of Medicine, McMaster University, Hamilton, Ontario, Canada
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22
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Abstract
The paper reviews findings in humans regarding interindividual differences in sympathetic nerve activity. Data come predominantly from microneurographic multi- or single fibre recordings of sympathetic nerve activity in healthy subjects. Findings relate to interindividual differences in muscle sympathetic nerve activity (MSNA) during resting conditions and in response to surprising sensory stimuli. At rest there are marked interindividual differences in the number of multiunit MSNA bursts. At the single fibre level the differences are because of more vasoconstrictor fibres being active in subjects with high than in subjects with low number of bursts. There are inverse relationships between (i) sympathetic burst incidence and cardiac output (CO) and (ii) between sympathetic burst incidence and vascular responsiveness to noradrenaline. Both findings contribute to explaining the absence of correlation between resting levels of MSNA and blood pressure. Surprising visual, somatosensory or auditory stimuli of sufficient strength cause a short lasting inhibition of MSNA in approx. 50-60% of healthy subjects. In subjects who display significant inhibition, the stimulus-induced blood pressure increase is smaller than in subjects without inhibition. The underlying mechanism may be related to fear of blood/injury. It is concluded that analysis of interindividual differences in sympathetic activity improves the understanding of central nervous control of the circulation.
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Affiliation(s)
- B Gunnar Wallin
- Institute of Neuroscience and Physiology, The Sahlgrenska Academy at Göteborg University, Göteborg, Sweden.
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23
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Hirata K, Kadirvelu A, Kinjo M, Sciacca R, Sugioka K, Otsuka R, Choy A, Chow SK, Yoshiyama M, Yoshikawa J, Homma S, Lang CC. Altered coronary vasomotor function in young patients with systemic lupus erythematosus. ACTA ACUST UNITED AC 2007; 56:1904-9. [PMID: 17530717 DOI: 10.1002/art.22702] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Accelerated atherosclerosis is an important cause of morbidity and mortality in patients with systemic lupus erythematosus (SLE). Altered coronary microvascular function may act as a marker of changes that predispose to the development of significant coronary vascular disease. The purpose of this study was to compare coronary flow reserve (CFR) in a group of premenopausal women with SLE and a group of age-, sex-, and race-matched healthy control subjects. METHODS Coronary flow velocity in 18 premenopausal women with SLE (mean +/- SD age 29.4 +/- 5.9 years) and 19 matched healthy controls (mean +/- SD age 28.2 +/- 4.3 years) was assessed by transthoracic Doppler echocardiography after an overnight fast. The CFR was calculated as the ratio of hyperemic to baseline coronary blood flow velocity in the left anterior descending coronary artery. Hyperemia was induced by intravenous administration of adenosine triphosphate. RESULTS The mean +/- SD duration of SLE was 8.2 +/- 7.2 years (range 0.25-25 years), and the mean +/- SD score on the Systemic Lupus Erythematosus Disease Activity Index was 11.0 +/- 5.3 (range 4.0-21.0). Adequate recordings of flow velocity in the left anterior descending artery under both conditions were obtained using an ultrasound procedure in all study subjects. CFR was significantly lower in SLE patients as compared with control subjects (mean +/- SD 3.4 +/- 0.8 versus 4.5 +/- 0.5; P < 0.0001). CONCLUSION These findings provide evidence that coronary vasomotor function is impaired in patients with SLE and support the notion that many of these young patients have subclinical coronary artery disease.
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24
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Fryer RM, Segreti JA, Widomski DL, Franklin PH, Banfor PN, Koch KA, Nakane M, Wu-Wong JR, Cox BF, Reinhart GA. Systemic activation of the calcium sensing receptor produces acute effects on vascular tone and circulatory function in uremic and normal rats: focus on central versus peripheral control of vascular tone and blood pressure by cinacalcet. J Pharmacol Exp Ther 2007; 323:217-26. [PMID: 17636005 DOI: 10.1124/jpet.107.123901] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Calcium-sensing receptor (CaR) activation decreases serum parathyroid hormone (PTH) and Ca2+ and, despite long-term reductions in mean arterial blood pressure (MAP), may produce acute hypertension in rats, an effect we hypothesized was mediated by constriction of multiple vascular beds. Rats were subjected to 5/6 nephrectomy (NX) or no surgery (Normal); at 7 to 8 weeks, uremia animals were anesthetized and instrumented to record MAP and regional blood flow (carotid, mesenteric, and hindlimb). Cinacalcet [N-(1-naphthalen-1-ylethyl)-3-[3-(trifluoromethyl)phenyl]-propan-1-amine; 1, 3, and 10 mg/kg; 30 min/dose] was infused over 90 min. In NX rats, cinacalcet dose-dependently decreased ionized calcium (iCa2+), elicited a 90% reduction in PTH, and produced dose-dependent self-limiting increases in MAP (from 119 +/- 6 to 129 +/- 5, 142 +/- 4, and 145 +/- 3 mm Hg at the end of each infusion). At 1 mg/kg, carotid vascular resistance (CVR) and mesenteric vascular resistance (MVR) increased to 16 +/- 6 and 18 +/- 6% above baseline, respectively. Hindlimb vascular resistance (HVR) also trended upward (13 +/- 8%). At 3 mg/kg, increases in CVR (38 +/- 10%), MVR (40 +/- 8%), and HVR (39 +/- 14%) were exacerbated; at 10 mg/kg, values remained at or near these levels. The effects of cinacalcet in Normal rats were similar to NX and were attenuated by ganglionic blockade with hexamethonium at low doses but remained significantly elevated at higher doses. Thus, CaR activation acutely increases MAP in uremic and nonuremic rats, responses that occur in parallel to vasoconstriction in multiple vascular beds through both a central and peripheral mechanism of action. Moreover, subsequent mechanistic studies suggest that increases in MAP produced by cinacalcet may be mediated by reduced tonic NO synthase-dependent NO production subsequent to reductions in blood iCa2+.
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Affiliation(s)
- Ryan M Fryer
- Integrative Pharmacology, Global Pharmaceutical Research and Development, Abbott Laboratories, 100 Abbott Park Road, Abbott Park, IL 60064-6119, USA.
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25
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Pakdeechote P, Dunn WR, Ralevic V. Cannabinoids inhibit noradrenergic and purinergic sympathetic cotransmission in the rat isolated mesenteric arterial bed. Br J Pharmacol 2007; 152:725-33. [PMID: 17641668 PMCID: PMC2190027 DOI: 10.1038/sj.bjp.0707397] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND AND PURPOSE Noradrenaline and ATP are sympathetic co-transmitters. In the rat perfused mesenteric bed cannabinoids have been shown to modify the overall response to sympathetic nerve stimulation. This study has assessed whether cannabinoid receptor activation modulates differentially the noradrenergic and purinergic components of sympathetic vasoconstriction. EXPERIMENTAL APPROACH Rat mesenteric beds were perfused with physiological salt solution and the effects of cannabinoids on responses to nerve stimulation, or exogenous noradrenaline or alpha,beta-methylene ATP (alpha,beta-meATP; P2X receptor agonist) were determined after raising tone with U46619. The effects of cannabinoids on the noradrenaline and ATP components of sympathetic neurotransmission were assessed using the alpha 1-adrenoceptor antagonist, prazosin, or after P2X receptor desensitization with alpha,beta-meATP. KEY RESULTS Anandamide, WIN 55,212-2 and CP55,940 attenuated sympathetic neurogenic vasoconstrictor responses. The inhibitory actions of anandamide and WIN 55,212-2 were blocked by LY320135, a CB1 receptor antagonist, but not by SR144528, a CB2 receptor antagonist. The inhibitory actions of CP55,940 were unaffected by LY320135 and SR144528. WIN 55,212-3, the inactive S(-) enantiomer of WIN 55,212-2, had no effect on sympathetic neurogenic responses. None of the cannabinoids affected contractile responses to exogenous noradrenaline or alpha,beta-meATP. Anandamide and WIN 55,212-2 inhibited both the noradrenaline and ATP components of the sympathetic neurogenic contractile responses, with effects on the ATP component being most marked. CONCLUSIONS AND IMPLICATIONS These results indicate that prejunctional CB1-like receptors mediate the sympathoinhibitory action of anandamide and WIN 55,212-2, but not CP55,940, in the rat mesenteric bed. Cannabinoids inhibit both the noradrenergic and purinergic components of sympathetic neurotransmission.
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MESH Headings
- 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid/pharmacology
- Adenosine Triphosphate/analogs & derivatives
- Adenosine Triphosphate/pharmacology
- Adrenergic Fibers/drug effects
- Adrenergic Fibers/physiology
- Animals
- Arachidonic Acids/pharmacology
- Benzofurans/pharmacology
- Benzoxazines/pharmacology
- Camphanes/pharmacology
- Cannabinoids/pharmacology
- Cyclohexanols/pharmacology
- Dose-Response Relationship, Drug
- Electric Stimulation
- Endocannabinoids
- In Vitro Techniques
- Male
- Mesenteric Arteries/drug effects
- Mesenteric Arteries/innervation
- Mesenteric Arteries/physiology
- Morpholines/pharmacology
- Muscle Tonus/drug effects
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/innervation
- Muscle, Smooth, Vascular/physiology
- Naphthalenes/pharmacology
- Norepinephrine/pharmacology
- Perfusion
- Polyunsaturated Alkamides/pharmacology
- Prazosin/pharmacology
- Pyrazoles/pharmacology
- Rats
- Rats, Wistar
- Receptor, Cannabinoid, CB1/antagonists & inhibitors
- Receptor, Cannabinoid, CB2/antagonists & inhibitors
- Receptors, Purinergic P2/physiology
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Affiliation(s)
- P Pakdeechote
- Centre for Integrated Systems Biology & Medicine, School of Biomedical Sciences, University of Nottingham Nottingham, UK
| | - W R Dunn
- Centre for Integrated Systems Biology & Medicine, School of Biomedical Sciences, University of Nottingham Nottingham, UK
| | - V Ralevic
- Centre for Integrated Systems Biology & Medicine, School of Biomedical Sciences, University of Nottingham Nottingham, UK
- Author for correspondence:
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26
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Fang Y, Ding Z, Bi Y, Gong N, Liu Y, Wei L, Liu Z. Effect of vagotomy on dynamics of mesenteric lymphatic vessels in the rat. CHINESE J PHYSIOL 2007; 50:89-92. [PMID: 17608146] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/16/2023] Open
Abstract
The functional modulation of lymphatic vessels may be closely associated with intact structures of the vagus nerve. In the present study, the vagotomy was done in Wistar rat to investigate the effect of vagus nerves on dynamic changes of mesenteric lymphatic vessels. After denervation, the mesenteric lymphatics showed significant decreases in contraction rate, diameter in the static state and overall contractile activity under a microscopic observation. The lymphatic contraction rhythm and valve movement became irregular and inconsistent. These findings indicated that the lymphatic innervation might be an important factor for active lymph formation and transportation.
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Affiliation(s)
- Yunhai Fang
- Department of Anatomy, Shandong University School of Medicine, Jinan 250012, Shandong, PR China
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27
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Fresco P, Oliveira JMA, Kunc F, Soares AS, Rocha-Pereira C, Gonçalves J, Diniz C. A2A adenosine-receptor-mediated facilitation of noradrenaline release in rat tail artery involves protein kinase C activation and betagamma subunits formed after alpha2-adrenoceptor activation. Neurochem Int 2007; 51:47-56. [PMID: 17493708 DOI: 10.1016/j.neuint.2007.03.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2007] [Revised: 03/14/2007] [Accepted: 03/19/2007] [Indexed: 11/29/2022]
Abstract
This work aimed to investigate the molecular mechanisms involved in the interaction of alpha2-adrenoceptors and adenosine A2A-receptor-mediated facilitation of noradrenaline release in rat tail artery, namely the type of G-protein involved in this effect and the step or steps where the signalling cascades triggered by alpha2-adrenoceptors and A2A-receptors interact. The selective adenosine A2A-receptor agonist 2-p-(2-carboxy ethyl) phenethylamino-5'-N-ethylcarboxamidoadenosine (CGS 21680; 100 nM) enhanced tritium overflow evoked by trains of 100 pulses at 5 Hz. This effect was abolished by the selective adenosine A2A-receptor antagonist 5-amino-7-(2-phenyl ethyl)-2-(2-furyl)-pyrazolo-[4,3-e]-1,2,4-triazolo [1,5-c]pyrimidine (SCH 58261; 20 nM) and by yohimbine (1 microM). CGS 21680-mediated effects were also abolished by drugs that disrupted G(i/o)-protein coupling with receptors, PTX (2 microg/ml) or NEM (40 microM), by the anti-G(salpha) peptide (2 microg/ml) anti-G(betagamma) peptide (10 microg/ml) indicating coupling of A2A-receptors to G(salpha) and suggesting a crucial role for G(betagamma) subunits in the A(2A)-receptor-mediated enhancement of tritium overflow. Furthermore, phorbol 12-myristate 13-acetate (PMA; 1 microM) or forskolin (1 microM), direct activators of protein kinase C and of adenylyl cyclase, respectively, also enhanced tritium overflow. In addition, PMA-mediated effects were not observed in the presence of either yohimbine or PTX. Results indicate that facilitatory adenosine A2A-receptors couple to G(salpha) subunits which is essential, but not sufficient, for the release facilitation to occur, requiring the involvement of G(i/o)-protein coupling (it disappears after disruption of G(i/o)-protein coupling, PTX or NEM) and/or G(betagamma) subunits (anti-G(betagamma)). We propose a mechanism for the interaction in study suggesting group 2 AC isoforms as a plausible candidate for the interaction site, as these isoforms can integrate inputs from G(salpha) subunits (released after adenosine A2A-receptor activation; prime-activation), G(betagamma) subunits (released after activation of G(i/o)-protein coupled receptors) which can directly synergistically stimulate the prime-activated AC or indirectly via G(betagamma) activation of the PLC-PKC pathway.
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MESH Headings
- Adenylyl Cyclases/drug effects
- Adenylyl Cyclases/metabolism
- Adrenergic Agonists/pharmacology
- Adrenergic Antagonists/pharmacology
- Animals
- Arteries/drug effects
- Arteries/innervation
- Arteries/metabolism
- Enzyme Activation/drug effects
- Enzyme Activation/physiology
- GTP-Binding Protein beta Subunits/biosynthesis
- GTP-Binding Protein beta Subunits/drug effects
- GTP-Binding Protein gamma Subunits/biosynthesis
- GTP-Binding Protein gamma Subunits/drug effects
- Male
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/innervation
- Muscle, Smooth, Vascular/metabolism
- Norepinephrine/metabolism
- Protein Kinase C/drug effects
- Protein Kinase C/metabolism
- Protein Subunits/drug effects
- Protein Subunits/metabolism
- Rats
- Rats, Wistar
- Receptor Cross-Talk/drug effects
- Receptor Cross-Talk/physiology
- Receptor, Adenosine A2A/drug effects
- Receptor, Adenosine A2A/metabolism
- Receptors, Adrenergic, alpha-2/drug effects
- Receptors, Adrenergic, alpha-2/metabolism
- Receptors, G-Protein-Coupled/drug effects
- Receptors, G-Protein-Coupled/metabolism
- Signal Transduction/drug effects
- Signal Transduction/physiology
- Sympathetic Fibers, Postganglionic/drug effects
- Sympathetic Fibers, Postganglionic/metabolism
- Tail/blood supply
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Affiliation(s)
- Paula Fresco
- Serviço de Farmacologia, REQUIMTE/FARMA, Faculdade de Farmácia, Universidade do Porto, Rua Aníbal Cunha, 164, P 4050-047 Porto, Portugal.
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28
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Tan JH, Al Abed A, Brock JA. Inhibition of KATP channels in the rat tail artery by neurally released noradrenaline acting on postjunctional alpha2-adrenoceptors. J Physiol 2007; 581:757-65. [PMID: 17379634 PMCID: PMC2075182 DOI: 10.1113/jphysiol.2007.129536] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
In rat tail artery, activation of postjunctional alpha(2)-adrenoceptors by noradrenaline (NA) released from sympathetic axons produces a slow depolarization (NAD) of the smooth muscle through a decrease in K(+) conductance. In this study we used intracellular recording to investigate whether the K(+) channel involved is the ATP-sensitive K(+) (K(ATP)) channel. Changes in membrane resistance were monitored by measuring the time constant of decay of excitatory junction potentials. The K(ATP) channel blockers, glibenclamide (10 microm) and PNU 37883A (5 microm), depolarized the smooth muscle and increased membrane resistance. Conversely, the K(ATP) channel openers, pinacidil (0.1 and 0.5 microm) and levcromakalim (0.1 microm), hyperpolarized the smooth muscle and decreased membrane resistance. Activation of K(ATP) channels with calcitonin gene-related peptide (CGRP; 10 nM) also hyperpolarized the smooth muscle and decreased membrane resistance. The NAD was abolished by both glibenclamide and PNU 37883A but was potentiated by CGRP. However, unlike CGRP, the directly acting K(ATP) channel openers, pinacidil and levcromakalim, inhibited the NAD. The effects of other K(+) channel blockers were also determined. A high concentration of Ba(2+)(1 mM), which would be expected to block K(ATP) channels, abolished the NAD, whereas teteraethylammonium (1 mM) and 4-aminopyridine (1 mM) increased its amplitude. Apamin (0.5 microm) and a lower concentration of Ba(2+) (0.1 mM) did not affect the NAD. These findings indicate that activation of alpha(2)-adrenoceptors by neurally released NA depolarizes the membrane of vascular smooth muscle by inhibiting K(ATP) channels open in the resting membrane.
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MESH Headings
- Adamantane/analogs & derivatives
- Adamantane/pharmacology
- Adenosine Triphosphate/metabolism
- Animals
- Arteries/innervation
- Arteries/metabolism
- Calcitonin Gene-Related Peptide/pharmacology
- Cromakalim/pharmacology
- Dose-Response Relationship, Drug
- Electric Impedance
- Excitatory Postsynaptic Potentials
- Female
- Glyburide/pharmacology
- In Vitro Techniques
- Ion Channel Gating/drug effects
- Morpholines/pharmacology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/innervation
- Muscle, Smooth, Vascular/metabolism
- Norepinephrine/metabolism
- Pinacidil/pharmacology
- Potassium Channel Blockers/pharmacology
- Potassium Channels/drug effects
- Potassium Channels/metabolism
- Rats
- Rats, Wistar
- Receptors, Adrenergic, alpha-2/metabolism
- Sympathetic Nervous System/drug effects
- Sympathetic Nervous System/metabolism
- Tail/blood supply
- Time Factors
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Affiliation(s)
- Joy H Tan
- Prince of Wales Medical Research Institute, University of New South Wales, Barker Street, Randwick, NSW 2031, Australia
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29
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Abstract
1. The dorsomedial hypothalamus (DMH) plays a crucial role in mediating the cardiovascular responses to different stressors, including acute psychological stress and cold stress. Activation of neurons in the DMH evokes increases in arterial pressure and in the activity of sympathetic nerves innervating the heart, blood vessels and brown adipose tissue. The descending pathways from the DMH to the spinal sympathetic outflow include synapses with neurons in medullary nuclei and possibly other brain stem regions. 2. Recent studies from our and other laboratories have indicated that neurons in the rostral ventrolateral medulla (RVLM) and in the region of the raphe pallidus (RP) in the medulla are important components of the descending pathways that mediate the cardiovascular response to activation of the DMH. Neurons in the RP primarily mediate the sympathetic cardiac components of the DMH-evoked response, whereas the RVLM neurons primarily mediate the sympathetic vasomotor component. 3. Activation of DMH neurons not only increases heart rate and sympathetic vasomotor activity, but also resets the baroreceptor reflex such that it remains effective, without any decrease in sensitivity, over a higher operating range of arterial pressure. 4. Activation of 5-hydroxytryptamine 5-HT(1A) receptors in the medulla oblongata leads to a selective suppression of cardiac and sympathetic vasomotor components of the DMH-evoked response, but does not affect sympathetic reflex responses evoked from baroreceptors or chemoreceptors. Thus, central 5-HT(1A) receptors modulate cardiovascular responses evoked from the DMH in a highly potent but selective fashion.
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Affiliation(s)
- J Horiuchi
- Discipline of Physiology and Institute for Biomedical Research, The University of Sydney, Sydney, New South Wales, Australia.
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30
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Christ GJ, Hodges S. Molecular mechanisms of detrusor and corporal myocyte contraction: identifying targets for pharmacotherapy of bladder and erectile dysfunction. Br J Pharmacol 2006; 147 Suppl 2:S41-55. [PMID: 16465183 PMCID: PMC1751499 DOI: 10.1038/sj.bjp.0706627] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The Post-Genomic age presents many new challenges and opportunities for the improved understanding, diagnosis and treatment of human disease. The long-term goal is to identify molecular correlates of disease processes, and use this information to develop novel and more effective therapeutics. A major hurdle in this regard is ensuring that the molecular targets of interest are indeed relevant to the physiology and/or pathophysiology of the processes being studied, and, moreover, to determine if they are specific to the tissue/organ being investigated. As a first step in this direction, we have reviewed the literature pertaining to bladder and erectile physiology/pharmacology and dysfunction and attempted to summarize some of the critical molecular mechanisms regulating detrusor and corporal myocyte tone. Because of the vast amount of published data, we have limited the scope of this review to consideration of the calcium-mobilizing and calcium-sensitizing pathways in these cells. Despite obvious differences in phenotypic characteristics of the detrusor and corporal myocyte, there are some common molecular changes that may contribute to, for example, the increased myocyte contractility characteristic of bladder and erectile dysfunction (i.e. increased Rho kinase activity and decreased K(+) channel function). Of course, there are also some important distinctions in the pathways that modulate contractility in these two cell types (i.e. the contribution of ryanodine-sensitive calcium stores and the nitric oxide/cGMP pathways). This report highlights some of these similarities and distinctions in the hope that it will encourage scientific discourse and research activity in this area, eventually leading to an improved quality of life for those millions of individuals that are afflicted with bladder and erectile dysfunction.
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MESH Headings
- Animals
- Erectile Dysfunction/drug therapy
- Erectile Dysfunction/metabolism
- Erectile Dysfunction/physiopathology
- Humans
- Male
- Muscle Contraction
- Muscle, Smooth/innervation
- Muscle, Smooth/metabolism
- Muscle, Smooth, Vascular/innervation
- Muscle, Smooth, Vascular/metabolism
- Myocytes, Smooth Muscle/metabolism
- Penile Erection
- Penis/blood supply
- Penis/metabolism
- Signal Transduction
- Urinary Bladder/innervation
- Urinary Bladder/metabolism
- Urinary Bladder, Overactive/drug therapy
- Urinary Bladder, Overactive/metabolism
- Urinary Bladder, Overactive/physiopathology
- Urination
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Affiliation(s)
- George J Christ
- Wake Forest Institute for Regenerative Medicine, Wake Forest University Baptist Medical Center, Winston-Salem, NC 27157, USA.
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31
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Filosa JA, Bonev AD, Straub SV, Meredith AL, Wilkerson MK, Aldrich RW, Nelson MT. Local potassium signaling couples neuronal activity to vasodilation in the brain. Nat Neurosci 2006; 9:1397-1403. [PMID: 17013381 DOI: 10.1038/nn1779] [Citation(s) in RCA: 406] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2006] [Accepted: 09/06/2006] [Indexed: 11/08/2022]
Abstract
The mechanisms by which active neurons, via astrocytes, rapidly signal intracerebral arterioles to dilate remain obscure. Here we show that modest elevation of extracellular potassium (K+) activated inward rectifier K+ (Kir) channels and caused membrane potential hyperpolarization in smooth muscle cells (SMCs) of intracerebral arterioles and, in cortical brain slices, induced Kir-dependent vasodilation and suppression of SMC intracellular calcium (Ca2+) oscillations. Neuronal activation induced a rapid (<2 s latency) vasodilation that was greatly reduced by Kir channel blockade and completely abrogated by concurrent cyclooxygenase inhibition. Astrocytic endfeet exhibited large-conductance, Ca2+-sensitive K+ (BK) channel currents that could be activated by neuronal stimulation. Blocking BK channels or ablating the gene encoding these channels prevented neuronally induced vasodilation and suppression of arteriolar SMC Ca2+, without affecting the astrocytic Ca2+ elevation. These results support the concept of intercellular K+ channel-to-K+ channel signaling, through which neuronal activity in the form of an astrocytic Ca2+ signal is decoded by astrocytic BK channels, which locally release K+ into the perivascular space to activate SMC Kir channels and cause vasodilation.
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Affiliation(s)
- Jessica A Filosa
- Department of Pharmacology, 89 Beaumont Avenue, College of Medicine, University of Vermont, Burlington, Vermont 05405, USA
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32
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Fu Q, Shook RP, Okazaki K, Hastings JL, Shibata S, Conner CL, Palmer MD, Levine BD. Vasomotor sympathetic neural control is maintained during sustained upright posture in humans. J Physiol 2006; 577:679-87. [PMID: 17008377 PMCID: PMC1890429 DOI: 10.1113/jphysiol.2006.118158] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2006] [Accepted: 09/27/2006] [Indexed: 01/13/2023] Open
Abstract
Vasomotor sympathetic activity plays an important role in arterial pressure maintenance via the baroreflex during acute orthostasis in humans. If orthostasis is prolonged, blood pressure may be supported additionally by humoral factors with a possible reduction in sympathetic baroreflex sensitivity. We tested the hypothesis that baroreflex control of muscle sympathetic nerve activity (MSNA) decreases during prolonged upright posture. MSNA and haemodynamics were measured supine and during 45 min 60 deg upright tilt in 13 healthy individuals. Sympathetic baroreflex sensitivity was quantified using the slope of the linear correlation between MSNA and diastolic pressure during spontaneous breathing. It was further assessed as the relationship between MSNA and stroke volume, with stroke volume derived from cardiac output (C2H2 rebreathing) and heart rate. Total peripheral resistance was calculated from mean arterial pressure and cardiac output. We found that MSNA increased from supine to upright (17+/-8 (S.D.) versus 38+/-12 bursts min-1; P<0.01), and continued to increase to a smaller degree during sustained tilt (39+/-11, 41+/-12, 43+/-13 and 46+/-15 bursts min-1 after 10, 20, 30 and 45 min of tilt; between treatments P<0.01). Sympathetic baroreflex sensitivity increased from supine to upright (-292+/-180 versus -718+/-362 units beat-1 mmHg-1; P<0.01), but remained unchanged as tilting continued (-611+/-342 and -521+/-221 units beat-1 mmHg-1 after 20 and 45 min of tilt; P=0.49). For each subject, changes in MSNA were associated with changes in stroke volume (r=0.88+/-0.13, P<0.05), while total peripheral resistance was related to MSNA during 45 min upright tilt (r=0.82+/-0.15, P<0.05). These results suggest that the vasoconstriction initiated by sympathetic adrenergic nerves is maintained by ongoing sympathetic activation during sustained (i.e. 45 min) orthostasis without obvious changes in vasomotor sympathetic neural control.
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Affiliation(s)
- Qi Fu
- Institute for Exercise and Environmental Medicine, Presbyterian Hospital of Dallas, University of Texas Southwestern Medical Center at Dallas, TX 75231, USA
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Abstract
The sympathetic nervous system plays an essential role in the control of total peripheral vascular resistance and blood flow, by controlling the contraction of small arteries. Perivascular sympathetic nerves release ATP, norepinephrine (NE) and neuropeptide Y. This review summarizes our knowledge of the intracellular Ca2+ signals that are activated by ATP and NE, acting respectively on P2X1 and alpha1-adrenoceptors in arterial smooth muscle. Each neurotransmitter produces a unique type of post-synaptic Ca2+ signal and associated contraction. The neural release of ATP and NE is thought to vary markedly with the pattern of nerve activity, probably reflecting both pre- and post-synaptic mechanisms. Finally, we show that Ca2+ signaling during neurogenic contractions activated by trains of sympathetic nerve fiber action potentials are in fact significantly different from that elicited by simple bath application of exogenous neurotransmitters to isolated arteries (a common experimental technique), and end by identifying important questions remaining in our understanding of sympathetic neurotransmission and the physiological regulation of contraction of small arteries.
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MESH Headings
- Adenosine Triphosphate/metabolism
- Animals
- Calcium/metabolism
- Calcium Signaling/physiology
- Mesenteric Arteries/innervation
- Mesenteric Arteries/metabolism
- Mesenteric Arteries/physiology
- Muscle Contraction
- Muscle, Smooth, Vascular/innervation
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/physiology
- Neuropeptide Y/metabolism
- Norepinephrine/metabolism
- Norepinephrine/physiology
- Receptors, Adrenergic, alpha-1/metabolism
- Receptors, Purinergic P2/metabolism
- Receptors, Purinergic P2X
- Sympathetic Nervous System/metabolism
- Sympathetic Nervous System/physiology
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Affiliation(s)
- Wei-jin Zang
- Department of Pharmacology, Key Laboratory of Environment and Genes Related to Diseases of Ministry of Education, School of Medicine, Xi-an Jiaotong University, Xi-an 710061, China.
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34
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Villalba N, Stankevicius E, Garcia-Sacristán A, Simonsen U, Prieto D. Contribution of both Ca2+ entry and Ca2+ sensitization to the alpha1-adrenergic vasoconstriction of rat penile small arteries. Am J Physiol Heart Circ Physiol 2006; 292:H1157-69. [PMID: 17085536 DOI: 10.1152/ajpheart.01034.2006] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Sympathetic adrenergic nerves maintain the flaccid state of the penis through the tonic release of norepinephrine that contracts trabecular and arterial smooth muscle. Simultaneous measurements of intracellular Ca(2+) concentration ([Ca(2+)](i)) and tension and experiments with alpha-toxin-permeabilized arteries were performed in branches of the rat dorsal penile artery to investigate the intracellular Ca(2+) signaling pathways underlying alpha(1)-adrenergic vasoconstriction. Phenylephrine increased both [Ca(2+)](i) and tension, these increases being abolished by extracellular Ca(2+) removal and reduced by about 50% by the L-type Ca(2+) channel blocker nifedipine (0.3 microM). Non-L-type Ca(2+) entry through store-operated channels was studied by inhibiting the sarcoplasmic reticulum Ca(2+)-ATPase with cyclopiazonic acid (CPA). CPA (30 microM) induced variable phasic contractions that were abolished by extracellular Ca(2+) removal and by the store-operated channels antagonist 2-aminoethoxydiphenyl borate (2-APB, 50 microM) and largely inhibited by nifedipine (0.3 microM). CPA induced a sustained increase in [Ca(2+)](i) that was reduced in a Ca(2+)-free medium. Under conditions of L-type channels blockade, Ca(2+) readmission after store depletion with CPA evoked a sustained and marked elevation in [Ca(2+)](i) not coupled to contraction. 2-APB (50 microM) inhibited the rise in [Ca(2+)](i) evoked by CPA and the nifedipine-insensitive increases in both [Ca(2+)](i) and contraction elicited by phenylephrine. In alpha-toxin-permeabilized penile arteries, activation of G proteins with guanosine 5'-O-(3-thiotriphosphate) and of the alpha(1)-adrenoceptor with phenylephrine both enhanced the myofilament sensitivity to Ca(2+). This Ca(2+) sensitization was reduced by selective inhibitors of PKC, tyrosine kinase (TK), and Rho kinase (RhoK) by 43%, 67%, and 82%, respectively. As a whole, the present data suggest the alpha(1)-adrenergic vasoconstriction in penile small arteries involves Ca(2+) entry through both L-type and 2-APB-sensitive receptor-operated channels, as well as Ca(2+) sensitization mechanisms mediated by PKC, TK, and RhoK. A capacitative Ca(2+) entry coupled to noncontractile functions of the smooth muscle cell is also demonstrated.
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MESH Headings
- Adrenergic alpha-1 Receptor Agonists
- Adrenergic alpha-Agonists/pharmacology
- Animals
- Arteries/drug effects
- Arteries/metabolism
- Calcium Channel Blockers/pharmacology
- Calcium Channels, L-Type/drug effects
- Calcium Channels, L-Type/metabolism
- Calcium Signaling/drug effects
- Dose-Response Relationship, Drug
- Enzyme Inhibitors/pharmacology
- GTP-Binding Proteins/metabolism
- In Vitro Techniques
- Intracellular Signaling Peptides and Proteins/antagonists & inhibitors
- Intracellular Signaling Peptides and Proteins/metabolism
- Male
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/innervation
- Muscle, Smooth, Vascular/metabolism
- Penis/blood supply
- Phenylephrine/pharmacology
- Protein Kinase C/antagonists & inhibitors
- Protein Kinase C/metabolism
- Protein Serine-Threonine Kinases/antagonists & inhibitors
- Protein Serine-Threonine Kinases/metabolism
- Protein-Tyrosine Kinases/antagonists & inhibitors
- Protein-Tyrosine Kinases/metabolism
- Rats
- Rats, Wistar
- Receptors, Adrenergic, alpha-1/metabolism
- Sarcoplasmic Reticulum Calcium-Transporting ATPases/antagonists & inhibitors
- Sarcoplasmic Reticulum Calcium-Transporting ATPases/metabolism
- Sympathetic Nervous System/physiology
- Vasoconstriction/drug effects
- Vasoconstrictor Agents/pharmacology
- rho-Associated Kinases
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Affiliation(s)
- Nuria Villalba
- Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense de Madrid, 28040 Madrid, Spain
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35
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Fernandes L, D'Aprile A, Self G, McGuire M, Sew T, Henry P, Goldie R. A Rho-kinase inhibitor, Y-27632, reduces cholinergic contraction but not neurotransmitter release. Eur J Pharmacol 2006; 550:155-61. [PMID: 17010334 DOI: 10.1016/j.ejphar.2006.08.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2005] [Revised: 11/01/2005] [Accepted: 08/11/2006] [Indexed: 10/24/2022]
Abstract
This study examined the effects of the selective Rho-kinase inhibitor Y-27632 [(+)-(R)-trans-4-(1-aminoethyl)-(4-pyridyl)cyclohexanecarboxamide dihydrochloride]) on cholinergic nerve-mediated contraction and neurotransmitter release in murine and guinea-pig isolated tracheal preparations. In tracheal preparations obtained from both species, Y-27632 shifted carbachol concentration-effect curves to the right and reduced the maximal contractile response. Repeated electrical field stimulation (EFS) evoked transient, consistent and reproducible contractions in murine and guinea-pig tracheal preparations. Y-27632 inhibited these cholinergic nerve-mediated contractions in a concentration-dependent manner. EFS (0.1-30 Hz) elicited frequency-dependent cholinergic nerve-mediated contractile responses. In murine tracheal preparations, Y-27632 (3 microM and 10 microM) shifted frequency-response curves to EFS to the right by 5.5 and 13.0 fold respectively and markedly reduced the maximal contractile response. In murine and guinea-pig tracheal preparations loaded with [(3)H]-choline, Y-27632 (10 microM) significantly increased the EFS-induced outflow of radioactivity from airway cholinergic nerves by 27% and 54% respectively. Thus, Y-27632 inhibited both carbachol-induced and cholinergic nerve-mediated contractile responses. Conversely, Y-27632 increased neurotransmitter release from airway cholinergic nerves. However, since antagonism of acetylcholine-induced contraction by Y-27632 overwhelmed the increased neurotransmitter release, the overall effect of this Rho-kinase inhibitor was to inhibit cholinergic nerve-mediated contraction.
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Affiliation(s)
- Lynette Fernandes
- Western Australian Institute for Medical Research and Pharmacology Unit, School of Medicine and Pharmacology, University of Western Australia, Perth, Australia.
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36
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Tarasova OS, Puzdrova VA, Kalenchuk VU, Koshelev VB. [Elevation of the vascular smooth muscle sensitivity to effects of constrictors after denervation and under decreased blood pressure]. Biofizika 2006; 51:912-7. [PMID: 17131833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Changes in contractile activity of saphenous artery in normotensive rats and in rats with regional hypotension have been investigated. The abdominal aorta was partially occluded in Wistar rats distally to the renal arteries. Four weeks later, a 5-7-mm segment of the femoral nerve in one hindlimb was resected to denervate the saphenous artery. After two weeks, the isometric contraction of innervated and denervated saphenous artery segments was studied. In normotensive rats, the denervation augmented vessel sensitivity to noradrenaline, phenylephrine, serotonin, and KCl (in the presence of phentolamine). Chronic hypotension also augmented vessel sensitivity to constrictor agonists, whereas denervation did not result in further increase of sensitivity. In glyoxilic acid-stained preparations obtained from hypotensive rats, a reduced intensity of fluorescence of adrenergic fibers was observed. It was assumed that the higher sensitivity of vascular smooth muscle in hypotensive rats is due to functional disturbances of sympathetic innervation.
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37
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Abstract
Raynaud's phenomenon is due to transient cessation of blood flow to the digits of the hands or feet. An attack of Raynaud's phenomenon is classically manifested as triphasic color changes. The white phase is due to excessive vasoconstriction and cessation of regional blood flow. This phase is followed by a cyanotic phase, as the residual blood in the finger desaturates. The red phase is due to hyperemia as the attack subsides and blood flow is restored. An attack is frequently associated with pain and/or paresthesia due to sensory nerve ischemia. Variants of Raynaud's phenomenon include acrocyanosis and primary livedo reticularis, each of which is associated with reduced skin blood flow, exacerbated by cold or emotional upset. Raynaud's phenomenon in the absence of other disorders is primary Raynaud's phenomenon, or Raynaud's disease. The mechanisms of Raynaud's disease include increased activation of the sympathetic nerves, in response to cold or emotion; an impaired habituation of the cardiovascular response to stress may contribute. In addition, there appears to be a local fault, which is likely multifactorial. This local fault is due to an alteration in vascular function rather than vascular structure. The alteration in vascular function may be related to increased sensitivity to cold of the adrenergic receptors on the digital artery vascular smooth muscle. In some cases, locally released or systemically circulating vasoconstrictors may participate, including endothelin, 5-hydroxytryptamine and thromboxane. A deficiency or increased degradation of nitric oxide, possibly due to increased oxidative stress, may be involved in some cases. These recent pathophysiological insights may lead to new therapeutic options.
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MESH Headings
- Endothelins/metabolism
- Endothelium, Vascular/metabolism
- Endothelium, Vascular/physiopathology
- Female
- Habituation, Psychophysiologic
- Humans
- Male
- Muscle, Skeletal/innervation
- Muscle, Skeletal/metabolism
- Muscle, Smooth, Vascular/innervation
- Muscle, Smooth, Vascular/metabolism
- Nitric Oxide/metabolism
- Norepinephrine/metabolism
- Oxidative Stress
- Raynaud Disease/metabolism
- Raynaud Disease/physiopathology
- Receptors, Adrenergic, alpha-1/metabolism
- Receptors, Adrenergic, alpha-2/metabolism
- Serotonin/metabolism
- Sex Factors
- Skin/blood supply
- Skin/innervation
- Temperature
- Vasoconstriction
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Affiliation(s)
- John P Cooke
- Section of Vascular Medicine, Stanford University School of Medicine, 300 Pasteur Drive, Stanford, CA 94305-5406, USA.
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38
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Abstract
Brief, spatially localized Ca(2+) transients occur in the smooth muscle adjacent to perivascular nerves of small arteries during neurogenic contractions. We named these "junctional Ca(2+) transients" (jCaTs) and postulated that they arose from Ca(2+) entering smooth muscle cells through P2X(1) receptors activated by neurally released ATP. Nevertheless, the lack of potent, subtype-selective P2X-receptor antagonists made determining the exact molecular identity of the channels difficult. Here we used small, pressurized mesenteric arteries from P2X(1)-receptor-deficient mice (KO) to test the hypothesis that jCaTs arise from Ca(2+) entering the smooth muscle cell via P2X(1) receptors. In wild-type (WT) arteries, confocal microscopy of fluo-4 fluorescence during electrical field stimulation (EFS) of perivascular sympathetic nerves revealed jCaTs in the smooth muscle cells adjacent to the perivascular nerves, similar to those reported previously in rat arteries, and alpha-latrotoxin (2.5 nM) markedly increased the frequency of "spontaneous" jCaTs. In the KO arteries, however, neither EFS nor alpha-latrotoxin elicited any jCaTs. A potent P2X-receptor agonist, alpha,beta-methylene ATP (10.0 microM), elicited strong contractions and increased intracellular Ca(2+) concentration in WT arteries but elicited neither in KO arteries. A biphasic vasoconstriction in response to EFS was observed in WT arteries. In KO arteries, however, the initial rapid, transient component of the biphasic vasoconstriction was absent. The data support the hypothesis that jCaTs represent Ca(2+) that enters the smooth muscle cells through P2X(1) receptors activated by neurally released ATP and that this Ca(2+) is involved in the initial rapid component of the sympathetic neurogenic contraction.
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Affiliation(s)
- Christine Lamont
- Department of Physiology, University of Maryland, Baltimore, MD 21201, USA.
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39
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Abstract
In congestive heart failure (CHF), exaggerated sympathetic activation is observed during exercise, which elicits excess peripheral vasoconstriction. The mechanisms causing this abnormality are not fully understood. Central command is a central neural process that induces parallel activation of motor and cardiovascular systems. This study was undertaken to determine whether central command serves as a mechanism that contributes to the exaggerated sympathetic response to exercise in CHF. In decerebrated rats, renal and lumbar sympathetic nerve responses (RSNA and LSNA, respectively) to 30 s of fictive locomotion were examined. The fictive locomotion was induced by electrical stimulation of the mesencephalic locomotor region (MLR). The study was performed in control animals (fractional shortening > 40%) and animals with myocardial infarctions (MI; fractional shortening < 30%). With low stimulation of the MLR (current intensity = 20 microA), the sympathetic responses were not significantly different in the control (RSNA: +18 +/- 4%; LSNA: +3 +/- 2%) and MI rats (RSNA: +16 +/- 5%; LSNA: +8 +/- 3%). With intense stimulation of the MLR (50 microA), the responses were significantly greater in MI rats (RSNA: +127 +/- 15%; LSNA: +57 +/- 10%) than in the control rats (RSNA: +62 +/- 5%; LSNA: +21 +/- 6%). In this study, the data demonstrate that RSNA and LSNA responses to intense stimulation of the MLR are exaggerated in MI rats. We suggest that intense activation of central command may play a role in evoking exaggerated sympathetic activation and inducing excessive peripheral vasoconstriction during exercise in CHF.
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Affiliation(s)
- Satoshi Koba
- Penn State Heart and Vascular Institute, Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, Hershey, PA 17033, USA
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40
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Chen RF, Tseng WT, Zeng WT, Yen CT, Tsai ML. Frequency response characteristic of sympathetic mediated low-frequency blood pressure fluctuations in conscious rats. Auton Neurosci 2006; 128:48-52. [PMID: 16530023 DOI: 10.1016/j.autneu.2006.02.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2005] [Revised: 12/19/2005] [Accepted: 02/02/2006] [Indexed: 11/16/2022]
Abstract
A quantitative relationship between power densities of blood pressure (PBP) and sympathetic nerve activity (PSNA) in a low-frequency range (LF, 0.016-0.85 Hz), expressed as PSNA=PBPxax10bx(frequency) was proposed in pentobarbital-anesthetized rats. For evaluating the general applicability of this equation, the quantitative relationship of power density ratio Hf=PBP/PSNA across frequency was tested in a conscious state. Wistar rats were chronically instrumented with a femoral artery catheter and recording electrode around the renal sympathetic nerve. The blood pressure and renal sympathetic nerve activity were monitored both under pentobarbital anesthesia and in a conscious state. Linear regression analysis of the relationship between the frequency and logarithmic magnitude of the power density ratio in the LF range revealed excellent fit in both conditions (r=-0.96+/-0.01 and -0.93+/-0.01 for anesthetized and conscious rats, respectively). Comparing the regression lines, rats under pentobarbital anesthesia had significantly larger values for the y-intercept and slope compared to rats in a conscious state (y-intercepts: 0.80+/-0.09>0.53+/-0.08; slopes: -2.86+/-0.26>-1.62+/-0.21). Our results demonstrate that it is also feasible to use the weighted PBP in LF as a quantitative index of sympathetic variability in conscious rats, but the evaluation of possible complications controlling the regression parameters is called for.
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Affiliation(s)
- Ruei-Feng Chen
- Institute of Zoology and Department of Life Science, National Taiwan University, Taipei, Taiwan
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41
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Drummond PD. Immersion of the hand in ice water releases adrenergic vasoconstrictor tone in the ipsilateral temple. Auton Neurosci 2006; 128:70-5. [PMID: 16627008 DOI: 10.1016/j.autneu.2006.03.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2006] [Accepted: 03/08/2006] [Indexed: 02/07/2023]
Abstract
Immersion of the hand in painfully cold water induces cutaneous vasodilatation in the temples, more so ipsilaterally than contralaterally. To investigate the mechanism of this response, guanethidine or saline was administered by transcutaneous iontophoresis to a recording site in the temple of ten participants before they immersed one of their hands in ice water. Guanethidine displaces noradrenaline from sympathetic nerve terminals and inhibits sympathetic noradrenergic neurotransmission. Therefore, it was hypothesized that guanethidine pre-treatment would block vasodilatation mediated by release of sympathetic vasoconstrictor tone in cutaneous vessels in the temple. During hand immersion, increases in the amplitude of the pulse waveform detected by laser Doppler flowmetry were greater in the ipsilateral than contralateral temple (86% vs. 34% above baseline, p<0.05), and pre-treatment with guanethidine prevented this asymmetric response (ipsilateral response 21% above baseline and contralateral response 32%, difference not significant). Guanethidine also inhibited ipsilateral increases in cutaneous blood flow during hand immersion in responsive participants. These findings suggest that limb pain inhibited ipsilateral adrenergic vasoconstrictor outflow in the temple. Thus, the findings challenge the concept of the sympathetic nervous system as a "mass action" system that discharges in unison to meet environmental demands. Instead, they suggest that the sympathetic nervous system is highly differentiated, with separate control of discrete reflex pathways on each side of the body.
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Affiliation(s)
- Peter D Drummond
- School of Psychology, Murdoch University, Perth, 6150 Western Australia.
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42
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Abstract
Intracellular calcium concentration ([Ca2+]i) governs the contractile status of arteriolar smooth muscle cells (SMC). Although studied in vitro, little is known of SMC [Ca2+]idynamics during the local control of blood flow. We tested the hypothesis that the rise and fall of SMC [Ca2+]iunderlies arteriolar constriction and dilation in vivo. Aparenchymal segments of second-order arterioles (diameter 35 ± 2 μm) were prepared in the superfused cheek pouch of anesthetized hamsters ( n = 18) and perifused with the ratiometric dye fura PE-3 (AM) to load SMC (1 μM, 20 min). Resting SMC [Ca2+]iwas 406 ± 37 nM. Elevating superfusate O2from 0 to 21% produced constriction (11 ± 2 μm) that was unaffected by dye loading; [Ca2+]iincreased by 108 ± 53 nM ( n = 6, P < 0.05). Cycling of [Ca2+]iduring vasomotion (amplitude, 150 ± 53 nM; n = 4) preceded corresponding diameter changes (7 ± 1 μm) by ∼2 s. Microiontophoresis (1 μm pipette tip; 1 μA, 1 s) of phenylephrine (PE) transiently increased [Ca2+]iby 479 ± 64 nM ( n = 8, P < 0.05) with constriction (26 ± 3 μm). Flushing blood from the lumen with saline increased fluorescence at 510 nm by ∼45% during excitation at both 340 and 380 nm with no difference in resting [Ca2+]i, diameter or respective responses to PE ( n = 7). Acetylcholine microiontophoresis (1 μA, 1 s) transiently reduced resting SMC [Ca2+]iby 131 ± 21 nM ( n = 6, P < 0.05) with vasodilation (17 ± 1 μm). Superfusion of sodium nitroprusside (10 μM) transiently reduced SMC [Ca2+]iby 124 ± 18 nM ( n = 6, P < 0.05), whereas dilation (23 ± 5 μm) was sustained. Resolution of arteriolar SMC [Ca2+]iin vivo discriminates key signaling events that govern the local control of tissue blood flow.
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Affiliation(s)
- Johan Fredrik Brekke
- The John B. Pierce Laboratory and Department of Cellular and Molecular Physiology, Yale University School of Medicine, 290 Congress Ave., New Haven, Connecticut 06519, USA
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44
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Abstract
Triptans are specific agonists
of the serotonergic 5-HT1B/1D
receptors that have increasingly
been used in the treatment of
migraine and cluster headaches.
Though they are generally considered
safe, there have been a few
reports of myocardial infarction and
stroke associated with triptan use.
We report a patient who developed
spontaneous splenic infarction after
the use of sumatriptan for the treatment
of migraine headache.
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MESH Headings
- Causality
- Cerebral Arteries/drug effects
- Cerebral Arteries/innervation
- Cerebral Arteries/physiopathology
- Female
- Humans
- Middle Aged
- Migraine Disorders/drug therapy
- Migraine Disorders/physiopathology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/innervation
- Muscle, Smooth, Vascular/physiopathology
- Peptides/antagonists & inhibitors
- Peptides/metabolism
- Receptor, Serotonin, 5-HT1B/drug effects
- Receptor, Serotonin, 5-HT1B/metabolism
- Serotonin Receptor Agonists/adverse effects
- Spleen/diagnostic imaging
- Spleen/drug effects
- Spleen/pathology
- Splenic Artery/drug effects
- Splenic Artery/innervation
- Splenic Artery/physiopathology
- Splenic Infarction/chemically induced
- Splenic Infarction/diagnosis
- Splenic Infarction/physiopathology
- Sumatriptan/adverse effects
- Tomography, X-Ray Computed
- Vasoconstriction/drug effects
- Vasoconstriction/physiology
- Vasoconstrictor Agents/adverse effects
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Affiliation(s)
- Anju Arora
- Department of Internal Medicine, Western Pennsylvania Hospital, Temple University Program, Pittsburgh, PA 15224, USA.
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45
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Abstract
The brain is critically dependent on a continuous supply of blood to function. Therefore, the cerebral vasculature is endowed with neurovascular control mechanisms that assure that the blood supply of the brain is commensurate to the energy needs of its cellular constituents. The regulation of cerebral blood flow (CBF) during brain activity involves the coordinated interaction of neurons, glia, and vascular cells. Thus, whereas neurons and glia generate the signals initiating the vasodilation, endothelial cells, pericytes, and smooth muscle cells act in concert to transduce these signals into carefully orchestrated vascular changes that lead to CBF increases focused to the activated area and temporally linked to the period of activation. Neurovascular coupling is disrupted in pathological conditions, such as hypertension, Alzheimer disease, and ischemic stroke. Consequently, CBF is no longer matched to the metabolic requirements of the tissue. This cerebrovascular dysregulation is mediated in large part by the deleterious action of reactive oxygen species on cerebral blood vessels. A major source of cerebral vascular radicals in models of hypertension and Alzheimer disease is the enzyme NADPH oxidase. These findings, collectively, highlight the importance of neurovascular coupling to the health of the normal brain and suggest a therapeutic target for improving brain function in pathologies associated with cerebrovascular dysfunction.
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Affiliation(s)
- Helene Girouard
- Division of Neurobiology, Department of Neurology and Neuroscience, Weill Medical College of Cornell University, New York, New York, USA
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46
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Abstract
Astrocytes send processes to synapses and blood vessels, communicate with other astrocytes through gap junctions and by release of ATP, and thus are an integral component of the neurovascular unit. Electrical field stimulations in brain slices demonstrate an increase in intracellular calcium in astrocyte cell bodies transmitted to perivascular end-feet, followed by a decrease in vascular smooth muscle calcium oscillations and arteriolar dilation. The increase in astrocyte calcium after neuronal activation is mediated, in part, by activation of metabotropic glutamate receptors. Calcium signaling in vitro can also be influenced by adenosine acting on A2B receptors and by epoxyeicosatrienoic acids (EETs) shown to be synthesized in astrocytes. Prostaglandins, EETs, arachidonic acid, and potassium ions are candidate mediators of communication between astrocyte end-feet and vascular smooth muscle. In vivo evidence supports a role for cyclooxygenase-2 metabolites, EETs, adenosine, and neuronally derived nitric oxide in the coupling of increased blood flow to increased neuronal activity. Combined inhibition of the EETs, nitric oxide, and adenosine pathways indicates that signaling is not by parallel, independent pathways. Indirect pharmacological results are consistent with astrocytes acting as intermediaries in neurovascular signaling within the neurovascular unit. For specific stimuli, astrocytes are also capable of transmitting signals to pial arterioles on the brain surface for ensuring adequate inflow pressure to parenchymal feeding arterioles. Therefore, evidence from brain slices and indirect evidence in vivo with pharmacological approaches suggest that astrocytes play a pivotal role in regulating the fundamental physiological response coupling dynamic changes in cerebral blood flow to neuronal synaptic activity. Future work using in vivo imaging and genetic manipulation will be required to provide more direct evidence for a role of astrocytes in neurovascular coupling.
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Affiliation(s)
- Raymond C Koehler
- Department of Anesthesiology and Critical Care Medicine, The Johns Hopkins University, Baltimore, Maryland 21287, USA.
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47
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Overend J, Wilson WS, Martin W. Biphasic neurogenic vasodilatation in the bovine intraocular long posterior ciliary artery: involvement of nitric oxide and an additional unidentified neurotransmitter. Br J Pharmacol 2006; 145:1001-8. [PMID: 15912133 PMCID: PMC1576216 DOI: 10.1038/sj.bjp.0706264] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
We have investigated the neurogenic factors inducing relaxation in the intraocular segment of the bovine long posterior ciliary artery. In precontracted vessels, electrical field stimulation (EFS, 0.5-128 Hz, 10 s trains) in the presence of guanethidine (30 microM) evoked biphasic relaxation: optimal relaxation for the first and second components occurred at 10 and 50 s, respectively. The first component, but not the second, was abolished by L-NAME (100 microM) or ODQ (3 microM). Relaxation to exogenous CGRP (0.1-300 nM) was inhibited by the CGRP antagonist, CGRP(8-37) (1-5 microM), but neither component of neurogenic relaxation was affected. Preincubation with the sensory nerve excitotoxin, capsaicin (1 microM), had no effect on either the first or second components of neurogenic relaxation. Substance P (0.1 nM-0.1 microM) induced relaxation, but rapid and complete desensitisation occurred within minutes. Neither desensitisation to substance P (0.1 microM) nor incubation with the NK(1) antagonist, L-733,060 (0.3 microM), had any effect on the first or second components of neurogenic relaxation.VIP (0.1 nM-0.3 microM) induced relaxation and this was followed by substantial desensitisation. Neither desensitisation to VIP (0.6 microM) nor treatment with the protease, alpha-chymotrypsin (10 U ml(-1)), had any effect on the first or second components of neurogenic relaxation. The results indicate that nitric oxide mediates the first component of neurogenic relaxation in the bovine intraocular ciliary artery. The neurotransmitter mediating the second component remains to be determined but is unlikely to be CGRP, substance P or VIP.
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Affiliation(s)
- Jill Overend
- Division of Neuroscience & Biomedical Systems, Institute of Biomedical & Life Sciences, West Medical Building, University of Glasgow, Glasgow G12 8QQ, Scotland
| | - William S Wilson
- Division of Neuroscience & Biomedical Systems, Institute of Biomedical & Life Sciences, West Medical Building, University of Glasgow, Glasgow G12 8QQ, Scotland
| | - William Martin
- Division of Neuroscience & Biomedical Systems, Institute of Biomedical & Life Sciences, West Medical Building, University of Glasgow, Glasgow G12 8QQ, Scotland
- Author for correspondence:
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48
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Abstract
The cerebrovascular endothelium exerts a profound influence on cerebral vessels and cerebral blood flow. This review summarizes current knowledge of various dilator and constrictor mechanisms intrinsic to the cerebrovascular endothelium. The endothelium contributes to the resting tone of cerebral arteries and arterioles by tonically releasing nitric oxide (NO•). Dilations can occur by stimulated release of NO•, endothelium-derived hyperpolarization factor, or prostanoids. During pathological conditions, the dilator influence of the endothelium can turn to that of constriction by a variety of mechanisms, including decreased NO• bioavailability and release of endothelin-1. The endothelium may participate in neurovascular coupling by conducting local dilations to upstream arteries. Further study of the cerebrovascular endothelium is critical for understanding the pathogenesis of a number of pathological conditions, including stroke, traumatic brain injury, and subarachnoid hemorrhage.
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Affiliation(s)
- Jon Andresen
- Department of Anesthesiology, Baylor College of Medicine, One Baylor Plaza, Suite 434D, Houston, Texas 77030, USA.
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49
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Abstract
The hypothesis that the amplitude of the myogenic response is modulated by factors released from nerve endings was tested in rat tail small arteries. A pressure myograph in conjunction with direct stimulation of nerve endings by electrical field stimulation (EFS) was used to determine rat small artery contractile reactions. Vessel pretreatment with 10(- 5) M phentolamine abolished EFS-induced reactions completely indicating that they are mediated mainly by an adrenoceptor agonist, probably noradrenaline. In the absence and presence of 10(- 5) M phentolamine, vessel diameter changes in the pressure range from 10 to 120 mmHg were not different. Vessel stimulation by (i) EFS, (ii) noradrenaline, (iii) selective stimulation of alpha1- and alpha2-receptors, (iv) serotonin, or (v) vasopressin significantly reduced the diameter change induced by stepping pressure from 10 to 40 mmHg compared to unstimulated, control vessels. Vessel diameter changes induced by stepping pressure from 40 to 80 and from 80 to 120 mmHg, however, were not different in vessels stimulated with EFS and noradrenaline compared to controls. In conclusion, these data show that factors released from unstimulated adrenergic nerve endings (i.e., not stimulated by EFS) are not involved in the myogenic response. In contrast, factors released upon stimulation of nerve endings can modulate the amplitude of the myogenic response, but only at low pressures. Thus, the pressure range for myogenic blood flow autoregulation is extended to lower pressures. Myogenic autoregulation of blood flow at physiological pressures is unaltered.
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MESH Headings
- Adrenergic alpha-Antagonists/pharmacology
- Animals
- Arteries/drug effects
- Arteries/innervation
- Arteries/physiology
- Electric Stimulation
- Endothelium, Vascular
- In Vitro Techniques
- Male
- Muscle Tonus/drug effects
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/innervation
- Muscle, Smooth, Vascular/physiology
- Nerve Endings/physiology
- Norepinephrine/pharmacology
- Phentolamine/pharmacology
- Pressure
- Rats
- Rats, Inbred WKY
- Receptors, Adrenergic, alpha-1/drug effects
- Receptors, Adrenergic, alpha-1/physiology
- Receptors, Adrenergic, alpha-2/drug effects
- Receptors, Adrenergic, alpha-2/physiology
- Serotonin/pharmacology
- Tetrodotoxin/pharmacology
- Vasoconstrictor Agents/pharmacology
- Vasopressins/pharmacology
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Affiliation(s)
- Stephanie Anschütz
- Institute of Physiology, University of Rostock, PSF 100888, D-18055 Rostock, Germany
| | - Rudolf Schubert
- Institute of Physiology, University of Rostock, PSF 100888, D-18055 Rostock, Germany
- Author for correspondence:
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50
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Garutti I, Olmedilla L, Arnal D, Cruz A, Moreno N, Gonzalez-Aragoneses F, Barrigón S. Surgical upper thoracic sympathectomy reduces arterial oxygenation during one-lung ventilation. J Cardiothorac Vasc Anesth 2005; 19:703-4. [PMID: 16202918 DOI: 10.1053/j.jvca.2004.12.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2004] [Indexed: 11/11/2022]
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