1
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Azmi NH, Ismail N, Imam MU, Ooi DJ, Oslan SNH. Modulation of High-Fat Diet-Induced Brain Oxidative Stress by Ferulate-Rich Germinated Brown Rice Ethyl Acetate Extract. Molecules 2022; 27:molecules27154907. [PMID: 35956857 PMCID: PMC9369880 DOI: 10.3390/molecules27154907] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 07/16/2022] [Accepted: 07/18/2022] [Indexed: 11/16/2022] Open
Abstract
The oxidative stress resulting from the production of reactive oxygen species plays a vital role in inflammatory processes and is associated with neurodegenerative changes. In view of the ability of germinated brown rice (GBR) to improve learning and memory, this present study aimed to investigate the mechanistic basis of GBR’s neuroprotection in a high-fat diet (HFD)-induced oxidative changes in adult Sprague–Dawley rats. Ferulate-rich GBR ethyl acetate extract (GBR-EA; 100 mg/kg and 200 mg/kg body weight) was supplemented orally for the last 3 months of 6 months HFD feeding during the study. GBR-EA supplementation was found to improve lipid profile and serum antioxidant status, when compared to the HFD group. Elevated mRNA expressions of SOD1, SOD2, SOD3, Catalase, and GPX were demonstrated in the frontal cortex and hippocampus of GBR-EA treated animals. The pro-inflammatory changes induced by HFD in the hippocampus were attenuated by GBR-EA through the downregulation of CRP and TNF- α and upregulation of PPAR-γ. GBR also reduced the hippocampal mRNA expression and enzyme level of acetylcholinesterase. In conclusion, this study proposed the possible transcriptomic regulation of antioxidant and inflammation in neurodegenerative processes resulting from high cholesterol consumption, with an emphasis on GBR’s potential to ameliorate such changes.
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Affiliation(s)
- Nur Hanisah Azmi
- Faculty of Food Science and Nutrition, Universiti Malaysia Sabah, Kota Kinabalu 88400, Sabah, Malaysia;
- Correspondence: (N.H.A.); (N.I.)
| | - Norsharina Ismail
- Natural Medicines and Products Research Laboratory, Institute of Bioscience, Universiti Putra Malaysia (UPM), Serdang 43400, Selangor, Malaysia
- Correspondence: (N.H.A.); (N.I.)
| | - Mustapha Umar Imam
- Centre for Advanced Medical Research and Training, Usmanu Danfodiyo University, Sokoto P.M.B. 2346, Nigeria;
| | - Der Jiun Ooi
- Department of Oral Biology and Biomedical Sciences, Faculty of Dentistry, MAHSA University, Jenjarom 42610, Selangor, Malaysia;
| | - Siti Nur Hazwani Oslan
- Faculty of Food Science and Nutrition, Universiti Malaysia Sabah, Kota Kinabalu 88400, Sabah, Malaysia;
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2
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Xavier FE. Nitrergic perivascular innervation in health and diseases: Focus on vascular tone regulation. Acta Physiol (Oxf) 2020; 230:e13484. [PMID: 32336027 DOI: 10.1111/apha.13484] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 04/14/2020] [Accepted: 04/16/2020] [Indexed: 12/12/2022]
Abstract
For a long time, the vascular tone was considered to be regulated exclusively by tonic innervation of vasoconstrictor adrenergic nerves. However, accumulating experimental evidence has revealed the existence of nerves mediating vasodilatation, including perivascular nitrergic nerves (PNN), in a wide variety of mammalian species. Functioning of nitrergic vasodilator nerves is evidenced in several territories, including cerebral, mesenteric, pulmonary, renal, penile, uterine and cutaneous arteries. Nitric oxide (NO) is the main neurogenic vasodilator in cerebral arteries and acts as a counter-regulatory mechanism for adrenergic vasoconstriction in other vascular territories. In the penis, NO relaxes the vascular and cavernous smooth muscles leading to penile erection. Furthermore, when interacting with other perivascular nerves, NO can act as a neuromodulator. PNN dysfunction is involved in the genesis and maintenance of vascular disorders associated with arterial and portal hypertension, diabetes, ageing, obesity, cirrhosis and hormonal changes. For example defective nitrergic function contributes to enhanced sympathetic neurotransmission, vasoconstriction and blood pressure in some animal models of hypertension. In diabetic animals and humans, dysfunctional nitrergic neurotransmission in the corpus cavernosum is associated with erectile dysfunction. However, in some vascular beds of hypertensive and diabetic animals, an increased PNN function has been described as a compensatory mechanism to the increased vascular resistance. The present review summarizes current understanding on the role of PNN in control of vascular tone, its alterations under different conditions and the associated mechanisms. The knowledge of these changes can serve to better understand the mechanisms involved in these disorders and help in planning new treatments.
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Affiliation(s)
- Fabiano E. Xavier
- Departamento de Fisiologia e Farmacologia Centro de Biociências Universidade Federal de Pernambuco Recife Brazil
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3
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Roloff EVL, Tomiak‐Baquero AM, Kasparov S, Paton JFR. Parasympathetic innervation of vertebrobasilar arteries: is this a potential clinical target? J Physiol 2016; 594:6463-6485. [PMID: 27357059 PMCID: PMC5108906 DOI: 10.1113/jp272450] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 06/18/2016] [Indexed: 12/25/2022] Open
Abstract
This review aims to summarise the contemporary evidence for the presence and function of the parasympathetic innervation of the cerebral circulation with emphasis on the vertebral and basilar arteries (the posterior cerebral circulation). We consider whether the parasympathetic innervation of blood vessels could be used as a means to increase cerebral blood flow. This may have clinical implications for pathologies associated with cerebral hypoperfusion such as stroke, dementia and hypertension. Relative to the anterior cerebral circulation little is known of the origins and neurochemical phenotypes of the parasympathetic innervation of the vertebrobasilar arteries. These vessels normally provide blood flow to the brainstem and cerebellum but can, via the Circle of Willis upon stenosis of the internal carotid arteries, supply blood to the anterior cerebral circulation too. We review the multiple types of parasympathetic fibres and their distinct transmitter mechanisms and how these vary with age, disease and species. We highlight the importance of parasympathetic fibres for mediating the vasodilatory response to sympathetic activation. Current trials are investigating the possibility of electrically stimulating the postganglionic parasympathetic ganglia to improve cerebal blood flow to reduce the penumbra following stroke. We conclude that although there are substantial gaps in our understanding of the origins of parasympathetic innervation of the vertebrobasilar arteries, activation of this system under some conditions might bring therapeutic benefits.
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Affiliation(s)
- Eva v. L. Roloff
- School of Physiology, Pharmacology and Neuroscience, Biomedical SciencesUniversity of BristolBristolBS8 1TDUK
| | - Ana M. Tomiak‐Baquero
- School of Physiology, Pharmacology and Neuroscience, Biomedical SciencesUniversity of BristolBristolBS8 1TDUK
| | - Sergey Kasparov
- School of Physiology, Pharmacology and Neuroscience, Biomedical SciencesUniversity of BristolBristolBS8 1TDUK
| | - Julian F. R. Paton
- School of Physiology, Pharmacology and Neuroscience, Biomedical SciencesUniversity of BristolBristolBS8 1TDUK
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4
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Harazny JM, Schmieder RE, Welzenbach J, Michelson G. Local application of tropicamide 0.5% reduces retinal capillary blood flow. Blood Press 2013; 22:371-6. [PMID: 23597124 DOI: 10.3109/08037051.2013.782956] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
INTRODUCTION Scanning laser Doppler flowmetry (SLDF) plays an important role in the study of arterial hypertension, diabetes and stroke. The technology enables non-invasive measurement of the retinal capillary perfusion (RCF), retinal haemodynamics and arteriolar morphology in human. The values can be measured in mydriasis or in non-mydriatic eyes. It is not clear whether the using of vasoactive mydriatica for pupil dilation affects the measured parameters in retina. Acetylcholine, a vasoactive neurotransmitter in human retina, affects the contractility of pericytes using muscarinic receptors and stimulates endothelial synthesis of nitric oxide (NO). We examined whether blockade of the retinal cholinergic receptors by tropicamide affects the RCF. METHODS We measured RCF in both eyes of 13 healthy subjects before and 30 min after the local application of one drop of 0.5% tropicamide to the right eye. The mean age of the group was 44 ± 14 years. The left eye was used as control. RCF was measured by Heidelberg retina flowmetry. RESULTS Thirty minutes after local application of one drop of 0.5% tropicamide to the right eye RCF decreased significantly (p = 0.001) by 31.9 ± 13% but did not change in the control eye. The maximal decrease was observed 20 min after application of the tropicamide. CONCLUSION Locally administered tropicamide profoundly affects the RCF. Thus pupil dilatation impairs any assessment of retinal microcirculation.
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Affiliation(s)
- Joanna M Harazny
- Ophthalmology Department Friedrich-Alexander University , Erlangen , Germany
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5
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Ando K, Mitsuiki S, Itoh K, Kusaba H, Soh T, Tsukise A. Development of vasoactive intestinal polypeptide-immunoreactive nerves in the major cerebral arteries of the quail anterior circulation. J Vet Med Sci 2010; 71:1643-7. [PMID: 20046033 DOI: 10.1292/jvms.001643] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Development of cerebral perivascular nerves immunoreactive for vasoactive intestinal polypeptide (VIP) was investigated in the Japanese quails, using immunohistochemistry and quantitative analysis. VIP-immunoreactive (VIP-IR) nerves supplying the anterior circulation appeared on the cerebral carotid artery (CCA) at embryonic day 10 and on the cerebroethmoidal artery (CEA) after hatching. Nerves from the CCA increased greatly in number and spread progressively during successive embryonic stages, while those from the CEA were sparse all through the post-hatching stages, mostly remained limited to this vessel wall. The distribution of VIP-IR nerves to the respective major arteries of the anterior circulation from the two vascular routes was basically similar among post-hatching day (P) 15, P20, P30 and P50. Likewise, no clear statistical difference was observed with regard to the nerve density of the corresponding arteries in the four age groups. These findings suggest that VIP-IR innervation of the quail anterior circulation usually attains its mature pattern at the third week after hatching.
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Affiliation(s)
- Koichi Ando
- Biological Laboratory, Department of Applied Chemistry and Biochemistry, Faculty of Engineering, Kyushu Sangyo University, Higashi-ku, Fukuoka 813-8503, Japan
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6
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Jadhav V, Jabre A, Chen MF, Lee TJF. Presynaptic Prostaglandin E
2
EP
1
-Receptor Facilitation of Cerebral Nitrergic Neurogenic Vasodilation. Stroke 2009; 40:261-9. [DOI: 10.1161/strokeaha.108.516104] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Vikram Jadhav
- From the Department of Pharmacology (V.J., T.J.-F.L.), Southern Illinois University School of Medicine, Springfield, Ill; the Department of Neurosurgery (A.J.), Boston University Medical Center, Boston, Mass; the Department of Physiology and Pharmacology (V.J.), Loma Linda University School of Medicine, Loma Linda, Calif; and Research Department (T.J.-F.L., M.-F.C.), Buddhist Tzu Chi General Hospital and Tzu Chi University Center for Vascular Medicine (M.-F.C., T.J.-F.L.), College of Life Sciences,
| | - Anthony Jabre
- From the Department of Pharmacology (V.J., T.J.-F.L.), Southern Illinois University School of Medicine, Springfield, Ill; the Department of Neurosurgery (A.J.), Boston University Medical Center, Boston, Mass; the Department of Physiology and Pharmacology (V.J.), Loma Linda University School of Medicine, Loma Linda, Calif; and Research Department (T.J.-F.L., M.-F.C.), Buddhist Tzu Chi General Hospital and Tzu Chi University Center for Vascular Medicine (M.-F.C., T.J.-F.L.), College of Life Sciences,
| | - Mei-Fang Chen
- From the Department of Pharmacology (V.J., T.J.-F.L.), Southern Illinois University School of Medicine, Springfield, Ill; the Department of Neurosurgery (A.J.), Boston University Medical Center, Boston, Mass; the Department of Physiology and Pharmacology (V.J.), Loma Linda University School of Medicine, Loma Linda, Calif; and Research Department (T.J.-F.L., M.-F.C.), Buddhist Tzu Chi General Hospital and Tzu Chi University Center for Vascular Medicine (M.-F.C., T.J.-F.L.), College of Life Sciences,
| | - Tony Jer-Fu Lee
- From the Department of Pharmacology (V.J., T.J.-F.L.), Southern Illinois University School of Medicine, Springfield, Ill; the Department of Neurosurgery (A.J.), Boston University Medical Center, Boston, Mass; the Department of Physiology and Pharmacology (V.J.), Loma Linda University School of Medicine, Loma Linda, Calif; and Research Department (T.J.-F.L., M.-F.C.), Buddhist Tzu Chi General Hospital and Tzu Chi University Center for Vascular Medicine (M.-F.C., T.J.-F.L.), College of Life Sciences,
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7
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Koladiya RU, Jaggi AS, Singh N, Sharma BK. Beneficial Effects of Donepezil on Vascular Endothelial Dysfunction-Associated Dementia Induced by L-Methionine in Rats. ACTA ACUST UNITED AC 2009. [DOI: 10.1248/jhs.55.215] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
| | - Amteshwar Singh Jaggi
- Pharmacology Division, Department of Pharmaceutical Sciences and Drug Research, Punjabi University
| | - Nirmal Singh
- Pharmacology Division, Department of Pharmaceutical Sciences and Drug Research, Punjabi University
| | - Bhupesh Kumar Sharma
- Pharmacology Division, Department of Pharmaceutical Sciences and Drug Research, Punjabi University
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8
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Chan JYH, Wu CHY, Tsai CY, Cheng HL, Dai KY, Chan SHH, Chang AYW. Transcriptional up-regulation of nitric oxide synthase II by nuclear factor-kappaB at rostral ventrolateral medulla in a rat mevinphos intoxication model of brain stem death. J Physiol 2007; 581:1293-307. [PMID: 17395621 PMCID: PMC2170851 DOI: 10.1113/jphysiol.2007.130872] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2007] [Accepted: 03/20/2007] [Indexed: 12/17/2022] Open
Abstract
As the origin of a 'life-and-death' signal that reflects central cardiovascular regulatory failure during brain stem death, the rostral ventrolateral medulla (RVLM) is a suitable neural substrate for mechanistic delineation of this vital phenomenon. Using a clinically relevant animal model that employed the organophosphate pesticide mevinphos (Mev) as the experimental insult, we evaluated the hypothesis that transcriptional up-regulation of nitric oxide synthase I or II (NOS I or II) gene expression by nuclear factor-kappaB (NF-kappaB) on activation of muscarinic receptors in the RVLM underlies brain stem death. In Sprague-Dawley rats maintained under propofol anaesthesia, co-microinjection of muscarinic M2R (methoctramine) or M4R (tropicamide), but not M1R (pirenzepine) or M3R (4-diphenylacetoxy-N-dimethylpiperidinium) antagonist significantly reduced the enhanced NOS I-protein kinase G signalling ('pro-life' phase) or augmented NOS II-peroxynitrite cascade ('pro-death' phase) in ventrolateral medulla, blunted the biphasic increase and decrease in baroreceptor reflex-mediated sympathetic vasomotor tone that reflect the transition from life to death, and diminished the elevated DNA binding activity or nucleus-bound translocation of NF-kappaB in RVLM neurons induced by microinjection of Mev into the bilateral RVLM. However, NF-kappaB inhibitors (diethyldithiocarbamate or pyrrolidine dithiocarbamate) or double-stranded kappaB decoy DNA preferentially antagonized the augmented NOS II-peroxynitrite cascade and the associated cardiovascular depression exhibited during the 'pro-death' phase. We conclude that transcriptional up-regulation of NOS II gene expression by activation of NF-kappaB on selective stimulation of muscarinic M2 or M4 subtype receptors in the RVLM underlies the elicited cardiovascular depression during the 'pro-death' phase in our Mev intoxication model of brain stem death.
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Affiliation(s)
- Julie Y H Chan
- Department of Medical Education and Research, Kaohsiung Veterans General Hospital, and Center for Neuroscience, National Sun Yat-sen University, Kaohsiung 80424, Taiwan, Republic of China
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9
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Leffler CW, Parfenova H, Fedinec AL, Basuroy S, Tcheranova D. Contributions of astrocytes and CO to pial arteriolar dilation to glutamate in newborn pigs. Am J Physiol Heart Circ Physiol 2006; 291:H2897-904. [PMID: 16891404 PMCID: PMC1676252 DOI: 10.1152/ajpheart.00722.2006] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Astrocytes can act as intermediaries between neurons and cerebral arterioles to regulate vascular tone in response to neuronal activity. Release of glutamate from presynaptic neurons increases blood flow to match metabolic demands. CO is a gasotransmitter that can be related to neural function and blood flow regulation in the brain. The present study addresses the hypothesis that glutamatergic stimulation promotes perivascular astrocyte CO production and pial arteriolar dilation in the newborn brain. Experiments used anesthetized newborn pigs with closed cranial windows, piglet astrocytes, and cerebrovascular endothelial cells in primary culture and immunocytochemical visualization of astrocytic markers. Pial arterioles and arteries of newborn pigs are ensheathed by astrocytes visualized by glial fibrillary acidic protein staining. Treatment (2 h) of astrocytes in culture with L-2-alpha-aminoadipic acid (L-AAA), followed by 14 h in toxin free medium, dose-dependently increased cell detachment, suggesting injury. Conversely, 16 h of continuous exposure to L-AAA caused no decrease in endothelial cell attachment. In vivo, topical L-AAA (2 mM, 5 h) disrupted the cortical glia limitans histologically. Such treatment also eliminated pial arteriolar dilation to the astrocyte-dependent dilator ADP and to glutamate but not to isoproterenol or CO. Glutamate stimulated CO production by the brain surface that also was abolished following L-AAA. In contrast, tetrodotoxin blocked dilation to N-methyl-D-aspartate but not to glutamate, isoproterenol, or CO or the glutamate-induced increase in CO. The concurrent loss of CO production and pial arteriolar dilation to glutamate following astrocyte injury suggests astrocytes may employ CO as a gasotransmitter for glutamatergic cerebrovascular dilation.
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Affiliation(s)
- Charles W Leffler
- Dept. of Physiology, University of Tennessee, Memphis, TN 38163, USA.
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10
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Teixeira CE, Priviero FBM, Todd J, Webb RC. Vasorelaxing effect of BAY 41-2272 in rat basilar artery: involvement of cGMP-dependent and independent mechanisms. Hypertension 2006; 47:596-602. [PMID: 16391173 DOI: 10.1161/01.hyp.0000199914.36936.1b] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Decreases in intrinsic NO cause cerebral vasospasms because of the dysregulation of cGMP formation by NO-mediated pathways. Because 5-cyclopropyl-2-{1-(2-fluorobenzyl)-1H-pyrazolo[3,4-b]pyridin-3-yl}pyrimidin-4-ylamine (BAY 41-2272) is a potent soluble guanylyl cyclase (sGC) stimulator in an NO-independent manner, this study aimed to investigate the mechanisms underlying the relaxant effects of BAY 41-2272 in the rat basilar artery. BAY 41-2272 (0.0001 to 1 micromol/L) induced relaxations in a concentration-dependent manner, with pEC50 values of 8.13+/-0.03 and 7.63+/-0.05 in intact and denuded rings, respectively. The sGC inhibitor 1H-[1,2,4] oxadiazolo [4,3,-a]quinoxalin-1-one (ODQ) markedly displaced the curve for BAY 41-2272 to the right in intact or denuded rings (&10-fold). The NO synthesis inhibitor NG-nitro-L-arginine methyl ester caused a rightward shift in the curve for BAY 41-2272 (4-fold), whereas the phosphodiesterase type 5 inhibitor sildenafil enhanced BAY 41-2272-induced relaxations (3- to 4-fold). The Na+-K+-ATPase inhibitor ouabain caused 3-fold rightward shifts in the curves for BAY 41-2272. Ca2+-induced contractions in K+ depolarized rings were significantly attenuated by BAY 41-2272 in an ODQ-insensitive manner. The NO donor glyceryl trinitrate and BAY 41-2272 caused rightward shifts in the contractile responses to serotonin. Their coincubation caused a synergistic inhibition of serotonin-induced contractions. BAY 41-2272 and glyceryl trinitrate increased cGMP levels (but not cAMP) by 10-fold and 4-fold above baseline, respectively, in an ODQ-sensitive manner. cGMP levels increased by 50-fold after coincubation. BAY 41-2272 potently relaxes the rat basilar artery in a synergistic fashion with NO. Targeting the sGC with selective activators, such as BAY 41-2272, may represent a new therapy to treat cerebrovascular disease.
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Affiliation(s)
- Cleber E Teixeira
- Department of Physiology, Medical College of Georgia, Augusta, GA 30912-3000, USA.
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11
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Thengchaisri N, Rivers RJ. Remote arteriolar dilations caused by methacholine: a role for CGRP sensory nerves? Am J Physiol Heart Circ Physiol 2005; 289:H608-13. [PMID: 15764675 DOI: 10.1152/ajpheart.01290.2004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Remote vasodilation caused by arteriolar microapplication of acetylcholine cannot be completely attributed to passive cell-cell communication of a hyperpolarizing signal. The present study was undertaken to ascertain whether a neural component may be involved in the remote response. In the cheek pouch of anesthetized hamsters, methacholine (100 μM) was applied to the arteriole by micropipette for 5 s, and the arteriolar responses were measured at the site of application and at remote locations: 500 and 1,000 μm upstream from the application site. Superfusion with the local anesthetic bupivacaine attenuated a local dilatory response and abolished the conducted dilation response to methacholine. Localized micropipette application of bupivacaine 300 μm from the methacholine application site also attenuated the remote dilation but did not inhibit the local dilation. Blockade of neuromuscular transmission with botulinum neurotoxin A (1 U, 3 days), micropipette application of calcitonin gene-related peptide (CGRP) receptor inhibitor CGRP-(8–37) (10 μM) 300 μm upstream from the methacholine application site, and denervation of the CGRP sensory nerve by 2 days of capsaicin treatment reduced the conducted dilation response to methacholine but did not affect the local dilatory response. Together, these data support involvement of a TTX-insensitive nerve, specifically the CGRP containing nerve, in vascular communication. Understanding the effect of regulation of a novel neural network system on the vascular network may lead to a new insight into regulation of blood flow and intraorgan blood distribution.
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Affiliation(s)
- Naris Thengchaisri
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins Univ., 600 N. Wolfe St., Ross Rm. 351, Baltimore, MD 21287, USA
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12
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Abstract
Background and Purpose—
It is not known whether cerebral vasoprotective mechanisms in females include increased function of arterial K
+
channels. We hypothesized that vasodilator responses mediated by activation of inwardly rectifying K
+
(K
IR
) channels are greater in cerebral arteries of female versus male rats and that this is due to the effects of estrogen.
Methods—
Changes in basilar artery diameter were measured with a cranial window preparation in anesthetized Sprague-Dawley rats.
Results—
K
+
(5 and 10 mmol/L) caused greater vasodilatation in females (percent maximum, 21±3% and 58±7%, respectively) versus males (11±1% and 37±4%, respectively;
P
<0.05). In contrast, vasodilator responses to aprikalim (1 and 3 μmol/L) or acetylcholine (ACh, 1 and 10 μmol/L) did not differ between the genders. The selective K
IR
channel inhibitor barium ion (30 μmol/L) decreased basilar artery diameter in males but not females (−7±1% versus −2±1%,
P
<0.05) and selectively inhibited K
+
-induced vasodilatation by ≈50% in both groups. Ovariectomy of female rats resulted in smaller vasodilator effects of K
+
, and chronic treatment of these rats with 17β-estradiol (0.01 mg/kg per day for 7 days) normalized K+-induced vasodilatation. Furthermore, the selective M2 muscarinic ACh receptor antagonist methoctramine (1 μmol/L) increased responses to K
+
in males to levels equivalent to responses in females but had no effect on responses to K
+
in females.
Conclusions—
K
+
is a more powerful vasodilator in the female versus male cerebral circulation. This difference is estrogen dependent and could be due to a lack of M2 muscarinic ACh receptor–induced inhibition of K
IR
channel activation by K
+
in female cerebral arteries.
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13
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Sawatzky DA, Kingham PJ, Durcan N, McLean WG, Costello RW. Eosinophil-induced release of acetylcholine from differentiated cholinergic nerve cells. Am J Physiol Lung Cell Mol Physiol 2003; 285:L1296-304. [PMID: 12948933 DOI: 10.1152/ajplung.00107.2003] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
One immunological component of asthma is believed to be the interaction of eosinophils with parasympathetic cholinergic nerves and a consequent inhibition of acetylcholine muscarinic M2 receptor activity, leading to enhanced acetylcholine release and bronchoconstriction. Here we have used an in vitro model of cholinergic nerve function, the human IMR32 cell line, to study this interaction. IMR32 cells, differentiated in culture for 7 days, expressed M2 receptors. Cells were radiolabeled with [3H]choline and electrically stimulated. The stimulation-induced release of acetylcholine was prevented by the removal of Ca2+. The muscarinic M1/M2 receptor agonist arecaidine reduced the release of acetylcholine after stimulation (to 82 +/- 2% of control at 10(-7) M), and the M2 receptor antagonist AF-DX 116 increased it (to 175 +/- 23% of control at 10(-5) M), indicating the presence of a functional M2 receptor that modulated acetylcholine release. When human eosinophils were added to IMR32 cells, they enhanced acetylcholine release by 36 +/- 10%. This effect was prevented by inhibitors of adhesion of the eosinophils to the IMR32 cells. Pretreatment of IMR32 cells with 10 mM carbachol, to desensitize acetylcholine receptors, prevented the potentiation of acetylcholine release by eosinophils or AF-DX 116. Acetylcholine release was similarly potentiated (by up to 45 +/- 7%) by degranulation products from eosinophils that had been treated with N-formyl-methionyl-leucyl-phenylalanine or that had been in contact with IMR32 cells. Contact between eosinophils and IMR32 cells led to an initial increase in expression of M2 receptors, whereas prolonged exposure reduced M2 receptor expression.
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Affiliation(s)
- Deborah A Sawatzky
- Department of Pharmacology and Therapeutics, University of Liverpool L69 3GE, United Kingdom
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14
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Si ML, Lee TJF. Alpha7-nicotinic acetylcholine receptors on cerebral perivascular sympathetic nerves mediate choline-induced nitrergic neurogenic vasodilation. Circ Res 2002; 91:62-9. [PMID: 12114323 DOI: 10.1161/01.res.0000024417.79275.23] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
It has been suggested in isolated porcine cerebral arteries that stimulation by nicotine of alpha7-nicotinic acetylcholine receptors (alpha7-nAChRs) on sympathetic nerves, but not direct stimulation of parasympathetic nitrergic nerves, caused nitrergic neurogenic dilation. Direct evidence supporting this hypothesis has not been presented. The present study, which used in vitro tissue bath and confocal microscopy techniques, was designed to determine whether choline, a selective agonist for alpha7-nAChRs, induced sympathetic-dependent nitrergic dilation of porcine basilar arterial rings. Choline and several nAChR agonists induced exclusive relaxation of basilar arterial rings without endothelium. The relaxation was blocked by tetrodotoxin, nitro-L-arginine, guanethidine, and beta2-adrenoceptor antagonists. Furthermore, the relaxation was blocked by methyllycaconitine and alpha-bungarotoxin (preferential alpha7-nAChR antagonists) and mecamylamine but was not affected by dihydro-beta-erythroidine (a preferential alpha4-nAChR antagonist). Confocal microscopic study demonstrated that choline and nicotine induced significant calcium influx in cultured porcine superior cervical ganglionic cells but failed to affect calcium influx in cultured sphenopalatine ganglionic cells, providing direct evidence that choline and nicotine did not act directly on the parasympathetic nitrergic neurons. The increased calcium influx in superior cervical ganglionic cells was attenuated by alpha-bungarotoxin and methyllycaconitine but not by dihydro-beta-erythroidine. These results support our hypothesis that activation of alpha7-nAChRs on cerebral perivascular sympathetic nerves causes calcium influx and the release of norepinephrine, which then act on presynaptic beta2-adrenoceptors located on the neighboring nitrergic nerve terminals, resulting in NO release and vasodilation. Endogenous choline may play an important role in regulating cerebral sympathetic activity and vascular tone.
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Affiliation(s)
- Min-Liang Si
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, Ill 62794-9629, USA
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Stengel PW, Yamada M, Wess J, Cohen ML. M(3)-receptor knockout mice: muscarinic receptor function in atria, stomach fundus, urinary bladder, and trachea. Am J Physiol Regul Integr Comp Physiol 2002; 282:R1443-9. [PMID: 11959688 DOI: 10.1152/ajpregu.00486.2001] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Negative chronotropic and smooth muscle contractile responses to the nonselective muscarinic agonist carbamylcholine were compared in isolated tissues from M(3)-muscarinic receptor knockout and wild-type mice. Carbamylcholine (10(-8)-3.0 x 10(-5) M) induced a concentration-dependent decrease in atrial rate that was similar in atria from M(3)-receptor knockout and wild-type mice, indicating that M(3) receptors were not involved in muscarinic receptor-mediated atrial rate decreases. In contrast, the M(3) receptor was a major muscarinic receptor involved in smooth muscle contraction of stomach fundus, urinary bladder, and trachea, although differences existed in the extent of M(3)-receptor involvement among the tissues. Contraction to carbamylcholine was virtually abolished in urinary bladder from M(3)-receptor knockout mice, suggesting that contraction was predominantly due to M(3)-receptor activation. However, approximately 50-60% maximal contraction to carbamylcholine occurred in stomach fundus and trachea from M(3)-receptor knockout mice, indicating that contraction in these tissues was also due to M(2)-receptor activation. High concentrations of carbamylcholine relaxed the stomach fundus from M(3)-receptor knockout mice by M(1)-receptor activation. Thus M(3)-receptor knockout mice provided unambiguous evidence that M(3) receptors 1) play no role in carbamylcholine-induced atrial rate reduction, 2) are the predominant receptor mediating carbamylcholine-induced urinary bladder contractility, and 3) share contractile responsibility with M(2) receptors in mouse stomach fundus and trachea.
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Affiliation(s)
- Peter W Stengel
- Neuroscience Research, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana 46285, USA.
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Scichilone N, Permutt S, Togias A. The lack of the bronchoprotective and not the bronchodilatory ability of deep inspiration is associated with airway hyperresponsiveness. Am J Respir Crit Care Med 2001; 163:413-9. [PMID: 11179115 DOI: 10.1164/ajrccm.163.2.2003119] [Citation(s) in RCA: 131] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
In healthy subjects, deep inspiration (DI) acts both as a bronchodilator and a bronchoprotector. The latter is impaired in asthmatics. We have now evaluated whether the lack of bronchoprotection is related to bronchial hyperresponsiveness (BHR), and whether the bronchodilatory effect is also lost in asthmatics. Ten healthy subjects (PC20 > 75 mg/ml), 12 asthmatics with moderate to severe BHR (PC20 < 1 mg/ml), 14 asthmatics with mild to borderline BHR (1 < PC20 < 25 mg/ml), and 10 rhinitics with mild to borderline BHR (1 < PC20 < 25 mg/ml) underwent single-dose methacholine provocations inducing at least 20% reduction in FEV1 after 20 min of DI inhibition. To measure the bronchodilatory effect, DIs were taken immediately after the postmethacholine spirometry, and lung function was again tested. To measure the bronchoprotective effect, DIs were taken before the administration of spasmogen. All four groups achieved the same reductions in FEV1 and FVC, in the absence of deep breaths (analysis of variance [ANOVA], p = 0.49). Only healthy subjects showed bronchoprotection (percent bronchoprotection, mean +/- SEM; healthy: 79 +/- 4.0; asthmatics with moderate to severe BHR: 12 +/- 14.5; asthmatics with mild to borderline BHR: -7 +/- 19.7; rhinitics with mild to borderline BHR: 2 +/- 14.0). In contrast, DIs were able to partially reverse bronchial obstruction in all four groups, albeit percent bronchodilation in healthy subjects was somewhat stronger. The dissociation between bronchoprotection and bronchodilation suggests that the two effects involve different mechanisms.
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Affiliation(s)
- N Scichilone
- Division of Clinical Immunology, Department of Medicine, Johns Hopkins University, School of Medicine, Baltimore, Maryland, USA.
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