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Lindquist BE. Spreading depolarizations pose critical energy challenges in acute brain injury. J Neurochem 2024; 168:868-887. [PMID: 37787065 PMCID: PMC10987398 DOI: 10.1111/jnc.15966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 08/08/2023] [Accepted: 09/10/2023] [Indexed: 10/04/2023]
Abstract
Spreading depolarization (SD) is an electrochemical wave of neuronal depolarization mediated by extracellular K+ and glutamate, interacting with voltage-gated and ligand-gated ion channels. SD is increasingly recognized as a major cause of injury progression in stroke and brain trauma, where the mechanisms of SD-induced neuronal injury are intimately linked to energetic status and metabolic impairment. Here, I review the established working model of SD initiation and propagation. Then, I summarize the historical and recent evidence for the metabolic impact of SD, transitioning from a descriptive to a mechanistic working model of metabolic signaling and its potential to promote neuronal survival and resilience. I quantify the energetic cost of restoring ionic gradients eroded during SD, and the extent to which ion pumping impacts high-energy phosphate pools and the energy charge of affected tissue. I link energy deficits to adaptive increases in the utilization of glucose and O2, and the resulting accumulation of lactic acid and CO2 downstream of catabolic metabolic activity. Finally, I discuss the neuromodulatory and vasoactive paracrine signaling mediated by adenosine and acidosis, highlighting these metabolites' potential to protect vulnerable tissue in the context of high-frequency SD clusters.
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Affiliation(s)
- Britta E Lindquist
- Department of Neurology, University of California, San Francisco, California, USA
- Gladstone Institute of Neurological Diseases, San Francisco, California, USA
- Zuckerberg San Francisco General Hospital and Trauma Center, San Francisco, California, USA
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2
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Shuvaeva VN, Gorshkova OP. Age-Related Changes in the Contribution of Nitric Oxide and Potassium Channels to Dilation of Rat Pial Arteries. J EVOL BIOCHEM PHYS+ 2021. [DOI: 10.1134/s0022093021060193] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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3
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Gorshkova OP. Age-Related Changes in the Role of
Potassium Channels in Acetylcholine-Induced Dilation of Pial Arteries in Normotensive
and Spontaneously Hypertensive Rats. J EVOL BIOCHEM PHYS+ 2021. [DOI: 10.1134/s0022093021010051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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4
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Ghali MGZ, Arborelius UP, Veznedaroglu E, Spetzler RF, Yaşargil MG, Marchenko V. Galenic Pial Arteriovenous Fistulas in Adults. J Neurol Sci 2020; 416:117014. [PMID: 32652360 DOI: 10.1016/j.jns.2020.117014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 05/30/2020] [Accepted: 07/01/2020] [Indexed: 11/19/2022]
Abstract
BACKGROUND Vein of Galen aneurysmal malformations (VOGMs) are pial arteriovenous fistulas possessing Galenic venous drainage most commonly presenting during the neonatal period and infancy, with initial discovery during adulthood quite rare. OBJECTIVES AND METHODS We conducted a literature survey of the PubMed database in order to identify Galenic pial arteriovenous fistulas (GPAVFs) with major manifestation or initial presentation during adulthood. Inclusionary criteria included pial AVFs with Galenic drainage with major manifestation or initial presentation at, or older than, 18 years. Exclusionary criteria included exclusive pediatric onset of symptomatology attributable to GPAVFs without a new onset major presentation during adulthood, exclusive or major dural arterial supply, arteriovenous malformations with Galenic drainage, developmental venous anomalies with Galenic drainage, isolated varices or anomalies of the vein of Galen, and any lesions with uncertainty regarding true GPAVF nature. RESULTS Our search generated 1589 articles. Excluding duplicates, 26 cases met criteria for evaluation. Mean age was 34.1 +/- 2.53 years. Clinical presentations of GPAVFs among adults included headache, intracranial hemorrhage, seizures, and focal neurologic deficits. Management strategies included observation (n = 5), emergent ventriculostomy or Torkildsen shunt (n = 3), cerebrospinal fluid diversion via ventriculoperitoneal shunting (n = 4), microsurgical obliteration or thrombectomy (n = 4), transarterial and/or transvenous embolotherapeutic obliteration (n = 7), and concurrent embolotherapy and radiosurgical irradiation (n = 1). CONCLUSIONS GPAVFs in adults often present with symptomatology of mild severity and may be effectively managed conservatively, though occasionally present catastrophically or may be treated via cerebrospinal fluid diversion, microsurgical obliteration, or endovascular embolization. Severity sufficient to require emergent intervention portended a poor outcome.
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Affiliation(s)
- Michael George Zaki Ghali
- Department of Neurological Surgery Karolinska Institutet, Nobels väg 6, Solna and Alfred Nobels Allé 8, Huddinge SE-171 77, Stockholm, Sweden; Centrum för traumaforskning Karolinska Institutet, Nobels väg 6, Solna and Alfred Nobels Allé 8, Huddinge SE-171 77, Stockholm, Sweden.
| | - Ulf P Arborelius
- Department of Neurological Surgery Karolinska Institutet, Nobels väg 6, Solna and Alfred Nobels Allé 8, Huddinge SE-171 77, Stockholm, Sweden; Centrum för traumaforskning Karolinska Institutet, Nobels väg 6, Solna and Alfred Nobels Allé 8, Huddinge SE-171 77, Stockholm, Sweden
| | - Erol Veznedaroglu
- Director of the Drexel Neurosciences Institute, Robert A. Groff Chairman in Neurosurgery, Global Neurosciences Institute, Mercerville, NJ 08619, United States of America
| | - Robert F Spetzler
- Department of Neurological Surgery, Barrow Neurological Institute, 350 W Thomas Rd, Phoenix, AZ 85013, Phoenix, AZ 85013, United States of America
| | - M Gazi Yaşargil
- Department of Neurosurgery, Department of Neurophysiology, University Hospital Zurich, Rämistrasse 100, 8091 Zurich, Switzerland
| | - Vitaliy Marchenko
- Institut Fiziologii imeni O O Bogomolca Nacional'na akademia nauk Ukraini, Bogomoletz str. 4, Kiev 01024, Ukraine
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5
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Smith JF, Lemmey HA, Borysova L, Hiley CR, Dora KA, Garland CJ. Endothelial Nitric Oxide Suppresses Action-Potential-Like Transient Spikes and Vasospasm in Small Resistance Arteries. Hypertension 2020; 76:785-794. [PMID: 32713276 PMCID: PMC7418934 DOI: 10.1161/hypertensionaha.120.15491] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 05/27/2020] [Accepted: 07/01/2020] [Indexed: 11/16/2022]
Abstract
Endothelial dysfunction in small arteries is a ubiquitous, early feature of cardiovascular disease, including hypertension. Dysfunction reflects reduced bioavailability of endothelium-derived nitric oxide (NO) and depressed endothelium-dependent hyperpolarization that enhances vasoreactivity. We measured smooth muscle membrane potential and tension, smooth muscle calcium, and used real-time quantitative polymerase chain reaction in small arteries and isolated tubes of endothelium to investigate how dysfunction enhances vasoreactivity. Rat nonmyogenic mesenteric resistance arteries developed vasomotion to micromolar phenylephrine (α1-adrenoceptor agonist); symmetrical vasoconstrictor oscillations mediated by L-type voltage-gated Ca2+ channels (VGCCs). Inhibiting NO synthesis abolished vasomotion so nanomolar phenylephrine now stimulated rapid, transient depolarizing spikes in the smooth muscle associated with chaotic vasomotion/vasospasm. Endothelium-dependent hyperpolarization block also enabled phenylephrine-vasospasm but without spikes or chaotic vasomotion. Depolarizing spikes were Ca2+-based and abolished by either T-type or L-type VGCCs blockers with depressed vasoconstriction. Removing NO also enabled transient spikes/vasoconstriction to Bay K-8644 (L-type VGCC activator). However, these were abolished by the L-type VGCC blocker nifedipine but not T-type VGCC block. Phenylephrine also initiated T-type VGCC-transient spikes and enhanced vasoconstriction after NO loss in nonmyogenic arteries from spontaneously hypertensive rats. In contrast to mesenteric arteries, myogenic coronary arteries displayed transient spikes and further vasoconstriction spontaneously on loss of NO. T-type VGCC block abolished these spikes and additional vasoconstriction but not myogenic tone. Therefore, in myogenic and nonmyogenic small arteries, reduced NO bioavailability engages T-type VGCCs, triggering transient depolarizing spikes in normally quiescent vascular smooth muscle to cause vasospasm. T-type block may offer a means to suppress vasospasm without inhibiting myogenic tone mediated by L-type VGCCs.
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Affiliation(s)
- Josh F. Smith
- Department of Pharmacology, Universityxs of Oxford (J.F.S., H.A.L.L., L.B, K.A.D., C.J.G.)
| | - Hamish A.L. Lemmey
- Department of Pharmacology, Universityxs of Oxford (J.F.S., H.A.L.L., L.B, K.A.D., C.J.G.)
| | - Lyudmyla Borysova
- Department of Pharmacology, Universityxs of Oxford (J.F.S., H.A.L.L., L.B, K.A.D., C.J.G.)
| | - C. Robin Hiley
- From the Deptartment of Pharmacology, University of Cambridge (C.R.H.)
| | - Kim A. Dora
- Department of Pharmacology, Universityxs of Oxford (J.F.S., H.A.L.L., L.B, K.A.D., C.J.G.)
| | - Christopher J. Garland
- Department of Pharmacology, Universityxs of Oxford (J.F.S., H.A.L.L., L.B, K.A.D., C.J.G.)
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Ghali MGZ, Marchenko V, Yaşargil MG, Ghali GZ. Structure and function of the perivascular fluid compartment and vertebral venous plexus: Illumining a novel theory on mechanisms underlying the pathogenesis of Alzheimer's, cerebral small vessel, and neurodegenerative diseases. Neurobiol Dis 2020; 144:105022. [PMID: 32687942 DOI: 10.1016/j.nbd.2020.105022] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 06/13/2020] [Accepted: 07/15/2020] [Indexed: 01/14/2023] Open
Abstract
Blood dynamically and richly supplies the cerebral tissue via microvessels invested in pia matter perforating the cerebral substance. Arteries penetrating the cerebral substance derive an investment from one or two successive layers of pia mater, luminally apposed to the pial-glial basal lamina of the microvasculature and abluminally apposed to a series of aquaporin IV-studded astrocytic end feet constituting the soi-disant glia limitans. The full investment of successive layers forms the variably continuous walls of the periarteriolar, pericapillary, and perivenular divisions of the perivascular fluid compartment. The pia matter disappears at the distal periarteriolar division of the perivascular fluid compartment. Plasma from arteriolar blood sequentially transudates into the periarteriolar division of the perivascular fluid compartment and subarachnoid cisterns in precession to trickling into the neural interstitium. Fluid from the neural interstitium successively propagates into the venules through the subarachnoid cisterns and perivenular division of the perivascular fluid compartment. Fluid fluent within the perivascular fluid compartment flows gegen the net direction of arteriovenular flow. Microvessel oscillations at the central tendency of the cerebral vasomotion generate corresponding oscillations of within the surrounding perivascular fluid compartment, interposed betwixt the abluminal surface of the vessels and internal surface of the pia mater. The precise microanatomy of this most fascinating among designable spaces has eluded the efforts of various investigators to interrogate its structure, though most authors non-consensusly concur the investing layers effectively and functionally segregate the perivascular and subarachnoid fluid compartments. Enlargement of the perivascular fluid compartment in a variety of neurological disorders, including senile dementia of the Alzheimer's type and cerebral small vessel disease, may alternately or coordinately constitute a correlative marker of disease severity and a possible cause implicated in the mechanistic pathogenesis of these conditions. Venular pressures modulating oscillatory dynamic flow within the perivascular fluid compartment may similarly contribute to the development of a variety among neurological disorders. An intimate understanding of subtle features typifying microanatomy and microphysiology of the investing structures and spaces of the cerebral microvasculature may powerfully inform mechanistic pathophysiology mediating a variety of neurovascular ischemic, neuroinfectious, neuroautoimmune, and neurodegenerative diseases.
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Affiliation(s)
- Michael George Zaki Ghali
- Department of Neurological Surgery, University of California San Francisco, 505 Parnassus Street, San Francisco, CA 94143, United States; Department of Neurobiology and Anatomy, 2900 W. Queen Lane, Philadelphia, PA 19129, United States.
| | - Vitaliy Marchenko
- Department of Neurobiology and Anatomy, 2900 W. Queen Lane, Philadelphia, PA 19129, United States; Department of Neurophysiology, Bogomoletz Institute, Kyiv, Ukraine; Department of Neuroscience, Московский государственный университет имени М. В., Ломоносова GSP-1, Leninskie Gory, Moscow 119991, Russian Federation
| | - M Gazi Yaşargil
- Department of Neurosurgery, University Hospital Zurich Rämistrasse 100, 8091 Zurich, Switzerland
| | - George Zaki Ghali
- United States Environmental Protection Agency, Arlington, Virginia, USA; Emeritus Professor of Toxicology, Purdue University, West Lafayette, Indiana, USA
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7
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Tykocki NR, Boerman EM, Jackson WF. Smooth Muscle Ion Channels and Regulation of Vascular Tone in Resistance Arteries and Arterioles. Compr Physiol 2017; 7:485-581. [PMID: 28333380 DOI: 10.1002/cphy.c160011] [Citation(s) in RCA: 222] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Vascular tone of resistance arteries and arterioles determines peripheral vascular resistance, contributing to the regulation of blood pressure and blood flow to, and within the body's tissues and organs. Ion channels in the plasma membrane and endoplasmic reticulum of vascular smooth muscle cells (SMCs) in these blood vessels importantly contribute to the regulation of intracellular Ca2+ concentration, the primary determinant of SMC contractile activity and vascular tone. Ion channels provide the main source of activator Ca2+ that determines vascular tone, and strongly contribute to setting and regulating membrane potential, which, in turn, regulates the open-state-probability of voltage gated Ca2+ channels (VGCCs), the primary source of Ca2+ in resistance artery and arteriolar SMCs. Ion channel function is also modulated by vasoconstrictors and vasodilators, contributing to all aspects of the regulation of vascular tone. This review will focus on the physiology of VGCCs, voltage-gated K+ (KV) channels, large-conductance Ca2+-activated K+ (BKCa) channels, strong-inward-rectifier K+ (KIR) channels, ATP-sensitive K+ (KATP) channels, ryanodine receptors (RyRs), inositol 1,4,5-trisphosphate receptors (IP3Rs), and a variety of transient receptor potential (TRP) channels that contribute to pressure-induced myogenic tone in resistance arteries and arterioles, the modulation of the function of these ion channels by vasoconstrictors and vasodilators, their role in the functional regulation of tissue blood flow and their dysfunction in diseases such as hypertension, obesity, and diabetes. © 2017 American Physiological Society. Compr Physiol 7:485-581, 2017.
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Affiliation(s)
- Nathan R Tykocki
- Department of Pharmacology, University of Vermont, Burlington, Vermont, USA
| | - Erika M Boerman
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri, USA
| | - William F Jackson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan, USA
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Potassium Channels in Regulation of Vascular Smooth Muscle Contraction and Growth. ADVANCES IN PHARMACOLOGY (SAN DIEGO, CALIF.) 2016; 78:89-144. [PMID: 28212804 DOI: 10.1016/bs.apha.2016.07.001] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Potassium channels importantly contribute to the regulation of vascular smooth muscle (VSM) contraction and growth. They are the dominant ion conductance of the VSM cell membrane and importantly determine and regulate membrane potential. Membrane potential, in turn, regulates the open-state probability of voltage-gated Ca2+ channels (VGCC), Ca2+ influx through VGCC, intracellular Ca2+, and VSM contraction. Membrane potential also affects release of Ca2+ from internal stores and the Ca2+ sensitivity of the contractile machinery such that K+ channels participate in all aspects of regulation of VSM contraction. Potassium channels also regulate proliferation of VSM cells through membrane potential-dependent and membrane potential-independent mechanisms. VSM cells express multiple isoforms of at least five classes of K+ channels that contribute to the regulation of contraction and cell proliferation (growth). This review will examine the structure, expression, and function of large conductance, Ca2+-activated K+ (BKCa) channels, intermediate-conductance Ca2+-activated K+ (KCa3.1) channels, multiple isoforms of voltage-gated K+ (KV) channels, ATP-sensitive K+ (KATP) channels, and inward-rectifier K+ (KIR) channels in both contractile and proliferating VSM cells.
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9
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Di Marco LY, Farkas E, Martin C, Venneri A, Frangi AF. Is Vasomotion in Cerebral Arteries Impaired in Alzheimer's Disease? J Alzheimers Dis 2016; 46:35-53. [PMID: 25720414 PMCID: PMC4878307 DOI: 10.3233/jad-142976] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A substantial body of evidence supports the hypothesis of a vascular component in the pathogenesis of Alzheimer’s disease (AD). Cerebral hypoperfusion and blood-brain barrier dysfunction have been indicated as key elements of this pathway. Cerebral amyloid angiopathy (CAA) is a cerebrovascular disorder, frequent in AD, characterized by the accumulation of amyloid-β (Aβ) peptide in cerebral blood vessel walls. CAA is associated with loss of vascular integrity, resulting in impaired regulation of cerebral circulation, and increased susceptibility to cerebral ischemia, microhemorrhages, and white matter damage. Vasomotion— the spontaneous rhythmic modulation of arterial diameter, typically observed in arteries/arterioles in various vascular beds including the brain— is thought to participate in tissue perfusion and oxygen delivery regulation. Vasomotion is impaired in adverse conditions such as hypoperfusion and hypoxia. The perivascular and glymphatic pathways of Aβ clearance are thought to be driven by the systolic pulse. Vasomotion produces diameter changes of comparable amplitude, however at lower rates, and could contribute to these mechanisms of Aβ clearance. In spite of potential clinical interest, studies addressing cerebral vasomotion in the context of AD/CAA are limited. This study reviews the current literature on vasomotion, and hypothesizes potential paths implicating impaired cerebral vasomotion in AD/CAA. Aβ and oxidative stress cause vascular tone dysregulation through direct effects on vascular cells, and indirect effects mediated by impaired neurovascular coupling. Vascular tone dysregulation is further aggravated by cholinergic deficit and results in depressed cerebrovascular reactivity and (possibly) impaired vasomotion, aggravating regional hypoperfusion and promoting further Aβ and oxidative stress accumulation.
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Affiliation(s)
- Luigi Yuri Di Marco
- Centre for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield, UK
| | - Eszter Farkas
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Chris Martin
- Department of Psychology, University of Sheffield, Sheffield, UK
| | - Annalena Venneri
- Department of Neuroscience, University of Sheffield, Sheffield, UK.,IRCCS, Fondazione Ospedale S. Camillo, Venice, Italy
| | - Alejandro F Frangi
- Centre for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield, UK
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Karlin A. Membrane potential and Ca2+ concentration dependence on pressure and vasoactive agents in arterial smooth muscle: A model. ACTA ACUST UNITED AC 2016; 146:79-96. [PMID: 26123196 PMCID: PMC4485026 DOI: 10.1085/jgp.201511380] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
A mathematical model incorporating junctional and stretch-activated microdomains and 37 protein components describes the myogenic response in arterial smooth muscle cells. Arterial smooth muscle (SM) cells respond autonomously to changes in intravascular pressure, adjusting tension to maintain vessel diameter. The values of membrane potential (Vm) and sarcoplasmic Ca2+ concentration (Cain) within minutes of a change in pressure are the results of two opposing pathways, both of which use Ca2+ as a signal. This works because the two Ca2+-signaling pathways are confined to distinct microdomains in which the Ca2+ concentrations needed to activate key channels are transiently higher than Cain. A mathematical model of an isolated arterial SM cell is presented that incorporates the two types of microdomains. The first type consists of junctions between cisternae of the peripheral sarcoplasmic reticulum (SR), containing ryanodine receptors (RyRs), and the sarcolemma, containing voltage- and Ca2+-activated K+ (BK) channels. These junctional microdomains promote hyperpolarization, reduced Cain, and relaxation. The second type is postulated to form around stretch-activated nonspecific cation channels and neighboring Ca2+-activated Cl− channels, and promotes the opposite (depolarization, increased Cain, and contraction). The model includes three additional compartments: the sarcoplasm, the central SR lumen, and the peripheral SR lumen. It incorporates 37 protein components. In addition to pressure, the model accommodates inputs of α- and β-adrenergic agonists, ATP, 11,12-epoxyeicosatrienoic acid, and nitric oxide (NO). The parameters of the equations were adjusted to obtain a close fit to reported Vm and Cain as functions of pressure, which have been determined in cerebral arteries. The simulations were insensitive to ±10% changes in most of the parameters. The model also simulated the effects of inhibiting RyR, BK, or voltage-activated Ca2+ channels on Vm and Cain. Deletion of BK β1 subunits is known to increase arterial–SM tension. In the model, deletion of β1 raised Cain at all pressures, and these increases were reversed by NO.
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Affiliation(s)
- Arthur Karlin
- Department of Biochemistry and Molecular Biophysics, Department of Physiology and Cellular Biophysics, and Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY 10032
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Kerr PM, Wei R, Tam R, Sandow SL, Murphy TV, Ondrusova K, Lunn SE, Tran CHT, Welsh DG, Plane F. Activation of endothelial IKCa channels underlies NO-dependent myoendothelial feedback. Vascul Pharmacol 2015; 74:130-138. [PMID: 26362477 DOI: 10.1016/j.vph.2015.09.001] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2015] [Revised: 08/26/2015] [Accepted: 09/07/2015] [Indexed: 12/30/2022]
Abstract
Agonist-induced vasoconstriction triggers a negative feedback response whereby movement of charged ions through gap junctions and/or release of endothelium-derived (NO) limit further reductions in diameter, a mechanism termed myoendothelial feedback. Recent studies indicate that electrical myoendothelial feedback can be accounted for by flux of inositol trisphosphate (IP3) through myoendothelial gap junctions resulting in localized increases in endothelial Ca(2+) to activate intermediate conductance calcium-activated potassium (IKCa) channels, the resultant hyperpolarization then conducting back to the smooth muscle to attenuate agonist-induced depolarization and tone. In the present study we tested the hypothesis that activation of IKCa channels underlies NO-mediated myoendothelial feedback. Functional experiments showed that block of IP3 receptors, IKCa channels, gap junctions and transient receptor potential canonical type-3 (TRPC3) channels caused endothelium-dependent potentiation of agonist-induced increase in tone which was not additive with that caused by inhibition of NO synthase supporting a role for these proteins in NO-mediated myoendothelial feedback. Localized densities of IKCa and TRPC3 channels occurred at the internal elastic lamina/endothelial-smooth muscle interface in rat basilar arteries, potential communication sites between the two cell layers. Smooth muscle depolarization to contractile agonists was accompanied by IKCa channel-mediated endothelial hyperpolarization providing the first demonstration of IKCa channel-mediated hyperpolarization of the endothelium in response to contractile agonists. Inhibition of IKCa channels, gap junctions, TRPC3 channels or NO synthase potentiated smooth muscle depolarization to agonists in a non-additive manner. Together these data indicate that rather being distinct pathways for the modulation of smooth muscle tone, NO and endothelial IKCa channels are involved in an integrated mechanism for the regulation of agonist-induced vasoconstriction.
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Affiliation(s)
- Paul M Kerr
- Faculty of Health and Community Studies, MacEwan University, Robbins Health Learning Centre, Edmonton, Alberta T5J 4S2, Canada.
| | - Ran Wei
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AlbertaT6G 2H7, Canada.
| | - Raymond Tam
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AlbertaT6G 2H7, Canada.
| | - Shaun L Sandow
- Inflammation and Healing Cluster, Faculty of Science, Health, Education and Engineering, University of the Sunshine Coast, Maroochydore, Queensland 4558, Australia.
| | - Timothy V Murphy
- Department of Physiology, School of Medical Sciences, University of New South Wales, Sydney, NSW2052, Australia.
| | - Katarina Ondrusova
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AlbertaT6G 2H7, Canada.
| | - Stephanie E Lunn
- Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AlbertaT6G 2H7, Canada.
| | - Cam Ha T Tran
- Hotchkiss Brain and Libin Cardiovascular Research Institutes, Department of Physiology & Pharmacology, University of Calgary, AlbertaT2N-4N1, Canada.
| | - Donald G Welsh
- Hotchkiss Brain and Libin Cardiovascular Research Institutes, Department of Physiology & Pharmacology, University of Calgary, AlbertaT2N-4N1, Canada.
| | - Frances Plane
- Cardiovascular Research Centre, University of Alberta, Edmonton, AlbertaT6G 2H7, Canada; Department of Pharmacology, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AlbertaT6G 2H7, Canada.
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12
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Zhou P, Cheng CP, Li T, Ferrario CM, Cheng HJ. Modulation of cardiac L-type Ca2+ current by angiotensin-(1-7): normal versus heart failure. Ther Adv Cardiovasc Dis 2015; 9:342-53. [PMID: 26082338 DOI: 10.1177/1753944715587424] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
OBJECTIVE Recent evidence has shown that, in heart failure (HF), clinically relevant concentrations of angiotensin-(1-7) [Ang-(1-7)] counteracts angiotensin II induced cardiac depression and produces positive inotropic effects in both left ventricle (LV) and myocytes. However, the underlying electrophysiological mechanism is unclear. We investigated the role and mechanism of Ang-(1-7) on LV myocyte L-type calcium current (ICa,L) responses in normal state and in HF. METHOD We compared the effect of Ang-(1-7) (10(-5) M) on ICa,L responses in isolated LV myocytes obtained from 11 rats with isoproterenol (ISO) induced HF (3 months after 170 mg/kg subcutaneous for 2 days) and from 8 age-matched normal control rats by patch clamp technique. RESULTS In normal myocytes, compared with baseline, superfusion of Ang-(1-7) caused no significant changes in ICa,L (8.2 ± 0.2 versus 8.0 ± 0.3 pA/pF, p= not significant). In HF myocytes, the baseline ICa,L was significantly reduced (5.3 ± 0.1 versus 8.0 ± 0.3 pA/pF, p < 0.01). Ang-(1-7) produced a 21% increase in ICa,L (6.4±0.1 versus 5.3±0.1 pA/pF, p < 0.01). Pretreatment of HF myocytes with a nitric oxide (NO) synthase inhibitor (L-NAME, 10(-5) M) resulted in a significantly greater increase in ICa,L (28%, 8.4 ± 0.1 versus 6.5 ± 0.1 pA/pF, p < 0.01) during Ang-(1-7) superfusion. In contrast, during incubation with the bradykinin (BK) inhibitor HOE 140 (10(-6) M), Ang-(1-7) induced increase in ICa,L was significantly decreased. The Ang-(1-7) induced increase in ICa,L was abolished by [D-Ala(7)]-Ang-(1-7) (A-779, 10(-5) M). CONCLUSIONS HF alters the response of ICa,L to Ang-(1-7). In normal myocytes, Ang-(1-7) has no significant effect on ICa,L. However, in HF myocytes, Ang-(1-7) increases ICa,L. These effects are mediated by the Ang-(1-7) Mas receptors and involve activation of NO/BK pathways.
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Affiliation(s)
- Peng Zhou
- Section on Cardiovascular Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Che Ping Cheng
- Section on Cardiovascular Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Tiankai Li
- Section on Cardiovascular Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USADepartment of Cardiology, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Carlos M Ferrario
- Department of Surgery, Internal Medicine-Nephrology, and Physiology-Pharmacology, Wake Forest School of Medicine, Winston-Salem, NC, USA
| | - Heng-Jie Cheng
- Section on Cardiovascular Medicine, Wake Forest School of Medicine, Winston-Salem, NC 27157-1045, USAInstitute for Regenerative Medicine, Wake Forest School of Medicine, Winston-Salem, NC, USA
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13
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Abstract
Intrarenal autoregulatory mechanisms maintain renal blood flow (RBF) and glomerular filtration rate (GFR) independent of renal perfusion pressure (RPP) over a defined range (80-180 mmHg). Such autoregulation is mediated largely by the myogenic and the macula densa-tubuloglomerular feedback (MD-TGF) responses that regulate preglomerular vasomotor tone primarily of the afferent arteriole. Differences in response times allow separation of these mechanisms in the time and frequency domains. Mechanotransduction initiating the myogenic response requires a sensing mechanism activated by stretch of vascular smooth muscle cells (VSMCs) and coupled to intracellular signaling pathways eliciting plasma membrane depolarization and a rise in cytosolic free calcium concentration ([Ca(2+)]i). Proposed mechanosensors include epithelial sodium channels (ENaC), integrins, and/or transient receptor potential (TRP) channels. Increased [Ca(2+)]i occurs predominantly by Ca(2+) influx through L-type voltage-operated Ca(2+) channels (VOCC). Increased [Ca(2+)]i activates inositol trisphosphate receptors (IP3R) and ryanodine receptors (RyR) to mobilize Ca(2+) from sarcoplasmic reticular stores. Myogenic vasoconstriction is sustained by increased Ca(2+) sensitivity, mediated by protein kinase C and Rho/Rho-kinase that favors a positive balance between myosin light-chain kinase and phosphatase. Increased RPP activates MD-TGF by transducing a signal of epithelial MD salt reabsorption to adjust afferent arteriolar vasoconstriction. A combination of vascular and tubular mechanisms, novel to the kidney, provides for high autoregulatory efficiency that maintains RBF and GFR, stabilizes sodium excretion, and buffers transmission of RPP to sensitive glomerular capillaries, thereby protecting against hypertensive barotrauma. A unique aspect of the myogenic response in the renal vasculature is modulation of its strength and speed by the MD-TGF and by a connecting tubule glomerular feedback (CT-GF) mechanism. Reactive oxygen species and nitric oxide are modulators of myogenic and MD-TGF mechanisms. Attenuated renal autoregulation contributes to renal damage in many, but not all, models of renal, diabetic, and hypertensive diseases. This review provides a summary of our current knowledge regarding underlying mechanisms enabling renal autoregulation in health and disease and methods used for its study.
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Affiliation(s)
- Mattias Carlström
- Department of Medicine, Division of Nephrology and Hypertension and Hypertension, Kidney and Vascular Research Center, Georgetown University, Washington, District of Columbia; Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; and Department of Cell Biology and Physiology, UNC Kidney Center, and McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Christopher S Wilcox
- Department of Medicine, Division of Nephrology and Hypertension and Hypertension, Kidney and Vascular Research Center, Georgetown University, Washington, District of Columbia; Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; and Department of Cell Biology and Physiology, UNC Kidney Center, and McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - William J Arendshorst
- Department of Medicine, Division of Nephrology and Hypertension and Hypertension, Kidney and Vascular Research Center, Georgetown University, Washington, District of Columbia; Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; and Department of Cell Biology and Physiology, UNC Kidney Center, and McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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14
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Shui S, Wang X, Chiang JY, Zheng L. Far-infrared therapy for cardiovascular, autoimmune, and other chronic health problems: A systematic review. Exp Biol Med (Maywood) 2015; 240:1257-65. [PMID: 25716016 DOI: 10.1177/1535370215573391] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2014] [Accepted: 12/31/2014] [Indexed: 01/08/2023] Open
Abstract
Physical therapy (physiotherapy), a complementary and alternative medicine therapy, has been widely applied in diagnosing and treating various diseases and defects. Increasing evidence suggests that convenient and non-invasive far-infrared (FIR) rays, a vital type of physiotherapy, improve the health of patients with cardiovascular disease, diabetes mellitus, and chronic kidney disease. Nevertheless, the molecular mechanisms by which FIR functions remain elusive. Hence, the purpose of this study was to review and summarize the results of previous investigations and to elaborate on the molecular mechanisms of FIR therapy in various types of disease. In conclusion, FIR therapy may be closely related to the increased expression of endothelial nitric oxide synthase as well as nitric oxide production and may modulate the profiles of some circulating miRNAs; thus, it may be a beneficial complement to treatments for some chronic diseases that yields no adverse effects.
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Affiliation(s)
- Shanshan Shui
- School of Medical Engineering, Hefei University of Technology, Hefei 230009, China School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009, China
| | - Xia Wang
- School of Medical Engineering, Hefei University of Technology, Hefei 230009, China
| | - John Y Chiang
- Department of Computer Science & Engineering, National Sun Yat-Sen University, Kaohsiung 80424, Taiwan Department of Healthcare Administration and Medical Informatics, Kaohsiung Medical University, Kaohsiung 80708, Taiwan
| | - Lei Zheng
- School of Medical Engineering, Hefei University of Technology, Hefei 230009, China School of Biotechnology and Food Engineering, Hefei University of Technology, Hefei 230009, China
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15
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Chang JP, Sawisky GR, Davis PJ, Pemberton JG, Rieger AM, Barreda DR. Relationship between nitric oxide- and calcium-dependent signal transduction pathways in growth hormone release from dispersed goldfish pituitary cells. Gen Comp Endocrinol 2014; 206:118-29. [PMID: 25038498 DOI: 10.1016/j.ygcen.2014.07.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 07/05/2014] [Accepted: 07/08/2014] [Indexed: 11/17/2022]
Abstract
Nitric oxide (NO) and Ca(2+) are two of the many intracellular signal transduction pathways mediating the control of growth hormone (GH) secretion from somatotropes by neuroendocrine factors. We have previously shown that the NO donor sodium nitroprusside (SNP) elicits Ca(2+) signals in identified goldfish somatotropes. In this study, we examined the relationships between NO- and Ca(2+)-dependent signal transduction mechanisms in GH secretion from primary cultures of dispersed goldfish pituitary cells. Morphologically identified goldfish somatotropes stained positively for an NO-sensitive dye indicating they may be a source of NO production. In 2h static incubation experiments, GH release responses to the NO donor S-nitroso-N-acetyl-d,l-penicillamine (SNAP) were attenuated by CoCl2, nifedipine, verapamil, TMB-8, BHQ, and KN62. In column perifusion experiments, the ability of SNP to induce GH release was impaired in the presence of TMB-8, BHQ, caffeine, and thapsigargin, but not ryanodine. Caffeine-elicited GH secretion was not affected by the NO scavenger PTIO. These results suggest that NO-stimulated GH release is dependent on extracellular Ca(2+) availability and voltage-sensitive Ca(2+) channels, as well as intracellular Ca(2+) store(s) that possess BHQ- and/or thapsigargin-inhibited sarcoplasmic/endoplasmic reticulum Ca(2+)-ATPases, as well as TMB-8- and/or caffeine-sensitive, but not ryanodine-sensitive, Ca(2+)-release channels. Calmodulin kinase-II also likely participates in NO-elicited GH secretion but caffeine-induced GH release is not upstream of NO production. These findings provide insights into how NO actions many integrate with Ca(2+)-dependent signalling mechanisms in goldfish somatotropes and how such interactions may participate in the GH-releasing actions of regulators that utilize both NO- and Ca(2+)-dependent transduction pathways.
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Affiliation(s)
- John P Chang
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada.
| | - Grant R Sawisky
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
| | - Philip J Davis
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
| | - Joshua G Pemberton
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
| | - Aja M Rieger
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
| | - Daniel R Barreda
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada; Department of Agriculture, Forestry and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
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16
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Ke YM, Ou MC, Ho CK, Lin YS, Liu HY, Chang WA. Effects of somatothermal far-infrared ray on primary dysmenorrhea: a pilot study. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE : ECAM 2012; 2012:240314. [PMID: 23320024 PMCID: PMC3536333 DOI: 10.1155/2012/240314] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Revised: 11/26/2012] [Accepted: 11/29/2012] [Indexed: 11/17/2022]
Abstract
The purpose of this study was to assess the beneficial effects of using a far-infrared (FIR) belt on the management of patients with primary dysmenorrhea. This is the first study to determine the efficacy of somatothermal FIR using a parallel-arm randomized sham-controlled and double-blinded design with objective physical evidence and psychometric self-reports. Fifty-one Taiwanese women with primary dysmenorrhea were enrolled in the study. Results indicate that there was an increased abdominal temperature of 0.6°C and a 3.27% increase in abdominal blood flow in the FIR group (wearing FIR belt) compared to those in the control group (wearing sham belt). Verbal rating scale and numeric rating scale scores in the FIR group were both lower than those in the control group. Compared to the blank group (wearing no belt), the average dysmenorrhea pain duration of the FIR group was significantly reduced from 2.5 to 1.8 days, but there was no significant difference in the control group. These results demonstrate that the use of a belt made of far-infrared ceramic materials can reduce primary dysmenorrhea.
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Affiliation(s)
- Yu-Min Ke
- Department of Obstetrics and Gynecology, Taichung Veterans General Hospital, Taichung 40705, Taiwan
| | - Ming-Chiu Ou
- Department of Applied Cosmetology and Master Program of Cosmetic Science, Hungkuang University, Taichung 43302, Taiwan
| | - Cheng-Kun Ho
- Department of Applied Cosmetology and Master Program of Cosmetic Science, Hungkuang University, Taichung 43302, Taiwan
| | - Yung-Sheng Lin
- Department of Applied Cosmetology and Master Program of Cosmetic Science, Hungkuang University, Taichung 43302, Taiwan
| | - Ho-Yen Liu
- Department of Applied Cosmetology and Master Program of Cosmetic Science, Hungkuang University, Taichung 43302, Taiwan
| | - Wen-An Chang
- Department of Applied Cosmetology and Master Program of Cosmetic Science, Hungkuang University, Taichung 43302, Taiwan
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17
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Hai CM. Systems biology of HBOC-induced vasoconstriction. Curr Drug Discov Technol 2012; 9:204-11. [PMID: 21726185 DOI: 10.2174/157016312802650751] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Revised: 01/25/2011] [Accepted: 07/01/2011] [Indexed: 01/24/2023]
Abstract
Vasoconstriction is a major adverse effect of HBOCs. The use of a single drug for attenuating HBOC-induced vasoconstriction has been tried with limited success. Since HBOC causes disruptions at multiple levels of organization in the vascular system, a systems approach is helpful to explore avenues to counteract the effects of HBOC at multiple levels by targeting multiple sites in the system. A multi-target approach is especially appropriate for HBOC-induced vasoconstriction, because HBOC disrupts the cascade of amplification by NO-cGMP signaling and protein phosphorylation, ultimately resulting in vasoconstriction. Targeting multiple steps in the cascade may alter the overall gain of amplification, thereby limiting the propagation of disruptive effects through the cascade. As a result, targeting multiple sites may accomplish a relatively high overall efficacy at submaximal drug doses. Identifying targets and doses for developing a multi-target combination HBOC regimen for oxygen therapeutics requires a detailed understanding of the systems biology and phenotypic heterogeneity of the vascular system at multiple layers of organization, which can be accomplished by successive iterations between experimental studies and mathematical modeling at multiple levels of vascular systems and organ systems. Towards this goal, this article addresses the following topics: a) NO-scavenging by HBOC, b) HBOC autoxidation-induced reactive oxygen species generation and endothelial barrier dysfunction, c) NO- cGMP signaling in vascular smooth muscle cells, d) NO and cGMP-dependent regulation of contractile filaments in vascular smooth muscle cells, e) phenotypic heterogeneity of vascular systems, f) systems biology as an approach to developing a multi-target HBOC regimen.
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Affiliation(s)
- Chi-Ming Hai
- Department of Molecular Pharmacology, Physiology & Biotechnology, Brown University, Providence, RI 02912, USA.
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18
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McNeish AJ, Jimenez-Altayo F, Cottrell GS, Garland CJ. Statins and selective inhibition of Rho kinase protect small conductance calcium-activated potassium channel function (K(Ca)2.3) in cerebral arteries. PLoS One 2012; 7:e46735. [PMID: 23056429 PMCID: PMC3466297 DOI: 10.1371/journal.pone.0046735] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Accepted: 09/01/2012] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND In rat middle cerebral and mesenteric arteries the K(Ca)2.3 component of endothelium-dependent hyperpolarization (EDH) is lost following stimulation of thromboxane (TP) receptors, an effect that may contribute to the endothelial dysfunction associated with cardiovascular disease. In cerebral arteries, K(Ca)2.3 loss is associated with NO synthase inhibition, but is restored if TP receptors are blocked. The Rho/Rho kinase pathway is central for TP signalling and statins indirectly inhibit this pathway. The possibility that Rho kinase inhibition and statins sustain K(Ca)2.3 hyperpolarization was investigated in rat middle cerebral arteries (MCA). METHODS MCAs were mounted in a wire myograph. The PAR2 agonist, SLIGRL was used to stimulate EDH responses, assessed by simultaneous measurement of smooth muscle membrane potential and tension. TP expression was assessed with rt-PCR and immunofluorescence. RESULTS Immunofluorescence detected TP in the endothelial cell layer of MCA. Vasoconstriction to the TP agonist, U46619 was reduced by Rho kinase inhibition. TP receptor stimulation lead to loss of K(Ca)2.3 mediated hyperpolarization, an effect that was reversed by Rho kinase inhibitors or simvastatin. K(Ca)2.3 activity was lost in L-NAME-treated arteries, but was restored by Rho kinase inhibition or statin treatment. The restorative effect of simvastatin was blocked after incubation with geranylgeranyl-pyrophosphate to circumvent loss of isoprenylation. CONCLUSIONS Rho/Rho kinase signalling following TP stimulation and L-NAME regulates endothelial cell K(Ca)2.3 function. The ability of statins to prevent isoprenylation and perhaps inhibit of Rho restores/protects the input of K(Ca)2.3 to EDH in the MCA, and represents a beneficial pleiotropic effect of statin treatment.
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Affiliation(s)
- Alister J McNeish
- Reading School of Pharmacy, University of Reading, Reading, Berkshire, United Kingdom.
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19
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Porte Y, Morel JL. Learning on Jupiter, learning on the Moon: the dark side of the G-force. Effects of gravity changes on neurovascular unit and modulation of learning and memory. Front Behav Neurosci 2012; 6:64. [PMID: 23015785 PMCID: PMC3449275 DOI: 10.3389/fnbeh.2012.00064] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Accepted: 09/06/2012] [Indexed: 12/14/2022] Open
Abstract
On earth, gravity vector conditions the development of all living beings by physically imposing an axis along which to build their organism. Thus, during their whole life, they have to fight against this force not only to maintain their architectural organization but also to coordinate the communication between organs and keep their physiology in a balanced steady-state. In space, astronauts show physiological, psychological, and cognitive deregulations, ranging from bone decalcification or decrease of musculature, to depressive-like disorders, and spatial disorientation. Nonetheless, they are confronted to a great amount of physical changes in their environment such as solar radiations, loss of light-dark cycle, lack of spatial landmarks, confinement, and obviously a dramatic decrease of gravity force. It is thus very hard to selectively discriminate the strict role of gravity level alterations on physiological, and particularly cerebral, dysfunction. To this purpose, it is important to design autonomous models and apparatuses for behavioral phenotyping utilizable under modified gravity environments. Our team actually aims at working on this area of research.
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Affiliation(s)
- Yves Porte
- Université de Bordeaux Bordeaux, France ; Centre National de la Recherche Scientifique Unité Mixte de Recherche 5293, Institut des Maladies Neurodégénératives Talence, France
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20
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Munglue P, Eumkep G, Wray S, Kupittayanant S. The effects of watermelon (Citrullus lanatus) extracts and L-citrulline on rat uterine contractility. Reprod Sci 2012; 20:437-48. [PMID: 22991380 DOI: 10.1177/1933719112459223] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
In uterine smooth muscle, the effects of watermelon and its citrulline content are unknown. The aims of this study were therefore, to determine the effects of watermelon extract and citrulline on the myometrium and to investigate their mechanisms of action. The effects of extracts of watermelon flesh and rind and L-citrulline (64 μmol/L) were evaluated on 3 types of contractile activity; spontaneous, those elicited by potassium chloride (KCl) depolarization, or oxytocin (10 nmol/L) application in isolated rat uterus. Inhibitors of nitric oxide (NO) and its mechanisms of action, N ω-Nitro-L-arginine methyl ester hydrochloride (L-NAME, 100 μmol/L), LY83583 (1 μmol/L), and tetraethylamonium chloride (5 mmol/L), as well as Ca signaling pathways, were determined. Both flesh and rind extracts significantly decreased the force produced by all 3 mechanisms, in a dose-dependent manner. The extracts could also significantly decrease the force under conditions of sustained high Ca levels (depolarization and agonist) and when the force was produced only by sarcoplasmic reticulum (SR) Ca release. L-citrulline produced the same effects on force as watermelon extracts. With submaximal doses of extract, the additive effects of L-citrulline were found. The inhibitory effects of extracts and L-citrulline were reversed upon the addition of NO inhibitors, and pretreatment of tissues with these inhibitors prevented the actions of both extracts and L-citrulline. Thus, these data show that watermelon and citrulline are potent tocolytics, decreasing the force produced by calcium entry and SR release and arising by different pathways, including oxytocin stimulation. Their major mechanism is to stimulate the NO-cyclic guanosine monophosphate (cGMP) relaxant pathway.
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Affiliation(s)
- Phukphon Munglue
- Institute of Science, Suranaree University of Technology, Nakhon Ratchasima, Thailand
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21
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Kapela A, Nagaraja S, Parikh J, Tsoukias NM. Modeling Ca2+ signaling in the microcirculation: intercellular communication and vasoreactivity. Crit Rev Biomed Eng 2012; 39:435-60. [PMID: 22196162 DOI: 10.1615/critrevbiomedeng.v39.i5.50] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
A network of intracellular signaling pathways and complex intercellular interactions regulate calcium mobilization in vascular cells, arteriolar tone, and blood flow. Different endothelium-derived vasoreactive factors have been identified and the importance of myoendothelial communication in vasoreactivity is now well appreciated. The ability of many vascular networks to conduct signals upstream also is established. This phenomenon is critical for both short-term changes in blood perfusion as well as long-term adaptations of a vascular network. In addition, in a phenomenon termed vasomotion, arterioles often exhibit spontaneous oscillations in diameter. This is thought to improve tissue oxygenation and enhance blood flow. Experimentation has begun to reveal important aspects of the regulatory machinery and the significance of these phenomena for the regulation of local perfusion and oxygenation. Mathematical modeling can assist in elucidating the complex signaling mechanisms that participate in these phenomena. This review highlights some of the important experimental studies and relevant mathematical models that provide the current understanding of these mechanisms in vasoreactivity.
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Affiliation(s)
- Adam Kapela
- Department of Biomedical Engineering, Florida International University, Miami, FL, USA
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22
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Hashimoto T, Kiya M, Ohata H, Miyazaki T, Shibata K, Nobe K, Honda K. Spatiotemporal dynamics of intracellular calcium in the middle cerebral artery isolated from stroke-prone spontaneously hypertensive rats. Exp Physiol 2011; 97:265-76. [DOI: 10.1113/expphysiol.2011.061499] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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23
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The promise of inhibition of smooth muscle tone as a treatment for erectile dysfunction: where are we now? Int J Impot Res 2011; 24:49-60. [PMID: 21975566 DOI: 10.1038/ijir.2011.49] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Ten years ago, the inhibition of Rho kinase by intracavernosal injection of Y-27632 was found to induce an erectile response. This effect did not require activation of nitric oxide-mediated signaling, introducing a novel target pathway for the treatment of erectile dysfunction (ED), with potential added benefit in cases where nitric oxide bioavailability is attenuated (and thus phosphodiesterase type 5 (PDE5) inhibitors are less efficacious). Rho-kinase antagonists are currently being developed and tested for a wide range of potential uses. The inhibition of this calcium-sensitizing pathway results in blood vessel relaxation. It is also possible that blockade of additional smooth muscle contractile signaling mechanisms may have the same effect. In this review, we conducted an extensive search of pertinent literature using PUBMED. We have outlined the various pathways involved in the maintenance of penile smooth muscle tone and discussed the current potential benefit for the pharmacological inhibition of these targets for the treatment of ED.
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24
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Pradhan RK, Chakravarthy VS. Informational dynamics of vasomotion in microvascular networks: a review. Acta Physiol (Oxf) 2011; 201:193-218. [PMID: 20887358 DOI: 10.1111/j.1748-1716.2010.02198.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Vasomotion refers to spontaneous oscillation of small vessels observed in many microvascular beds. It is an intrinsic phenomenon unrelated to cardiac rhythm or neural and hormonal regulation. Vasomotion is found to be particularly prominent under conditions of metabolic stress. In spite of a significant existent literature on vasomotion, its physiological and pathophysiological roles are not clear. It is thought that modulation of vasomotion by vasoactive substances released by metabolizing tissue plays a role in ensuring optimal delivery of nutrients to the tissue. Vasomotion rhythms exhibit a great variety of temporal patterns from regular oscillations to chaos. The nature of vasomotion rhythm is believed to be significant to its function, with chaotic vasomotion offering several physiological advantages over regular, periodic vasomotion. In this article, we emphasize that vasomotion is best understood as a network phenomenon. When there is a local metabolic demand in tissue, an ideal vascular response should extend beyond local microvasculature, with coordinated changes over multiple vascular segments. Mechanisms of information transfer over a vessel network have been discussed in the literature. The microvascular system may be regarded as a network of dynamic elements, interacting, either over the vascular anatomical network via gap junctions, or physiologically by exchange of vasoactive substances. Drawing analogies with spatiotemporal patterns in neuronal networks of central nervous system, we ask if properties like synchronization/desynchronization of vasomotors have special significance to microcirculation. Thus the contemporary literature throws up a novel view of microcirculation as a network that exhibits complex, spatiotemporal and informational dynamics.
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Affiliation(s)
- R K Pradhan
- Biotechnology and Bioengineering Center, Medical College of Wisconsin, Milwaukee, WI 53226-6509, USA.
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25
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Yoo HY, Park SJ, Bahk JH, Kim SJ. Inhibition of hypoxic pulmonary vasoconstriction of rats by carbon monoxide. J Korean Med Sci 2010; 25:1411-7. [PMID: 20890419 PMCID: PMC2946648 DOI: 10.3346/jkms.2010.25.10.1411] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2010] [Accepted: 03/23/2010] [Indexed: 11/20/2022] Open
Abstract
Hypoxic pulmonary vasoconstriction (HPV), a unique response of pulmonary circulation, is critical to prevent hypoxemia under local hypoventilation. Hypoxic inhibition of K(+) channel is known as an important O(2)-sensing mechanism in HPV. Carbon monoxide (CO) is suggested as a positive regulator of Ca(2+)-activated K(+) channel (BK(Ca)), a stimulator of guanylate cyclase, and an O(2)-mimetic agent in heme moiety-dependent O(2) sensing mechanisms. Here we compared the effects of CO on the HPV (P(O(2)), 3%) in isolated pulmonary artery (HPV(PA)) and in blood-perfused/ventilated lungs (HPV(lung)) of rats. A pretreatment with CO (3%) abolished the HPV(PA) in a reversible manner. The inhibition of HPV(PA) was completely reversed by 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ), a guanylate cyclase inhibitor. In contrast, the HPV(lung) was only partly decreased by CO. Moreover, the partial inhibition of HPV(lung) by CO was affected neither by the pretreatment with ODQ nor by NO synthase inhibitor (L-NAME). The CO-induced inhibitions of HPV(PA) and HPV(lung) were commonly unaffected by tetraethylammonium (TEA, 2 mM), a blocker of BK(Ca). As a whole, CO inhibits HPV(PA) via activating guanylate cyclase. The inconsistent effects of ODQ on HPV(PA) and HPV(lung) suggest that ODQ may lose its sGC inhibitory action when applied to the blood-containing perfusate.
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Affiliation(s)
- Hae Young Yoo
- Department of Physiology, Seoul National University College of Medicine, Seoul, Korea
| | - Su Jung Park
- Department of Physiology, Seoul National University College of Medicine, Seoul, Korea
| | - Jae Hyon Bahk
- Department of Anesthesiology and Pain Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Sung Joon Kim
- Department of Physiology, Seoul National University College of Medicine, Seoul, Korea
- Ischemic/Hypoxic Disease Institute, Seoul National University College of Medicine, Seoul, Korea
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26
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McNeish AJ, Jimenez Altayo F, Garland CJ. Evidence both L-type and non-L-type voltage-dependent calcium channels contribute to cerebral artery vasospasm following loss of NO in the rat. Vascul Pharmacol 2010; 53:151-9. [PMID: 20601125 PMCID: PMC3191278 DOI: 10.1016/j.vph.2010.06.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Revised: 06/01/2010] [Accepted: 06/12/2010] [Indexed: 11/25/2022]
Abstract
We recently found block of NO synthase in rat middle cerebral artery caused spasm, associated with depolarizing oscillations in membrane potential (Em) similar in form but faster in frequency (circa 1 Hz) to vasomotion. T-type voltage-gated Ca2+ channels contribute to cerebral myogenic tone and vasomotion, so we investigated the significance of T-type and other ion channels for membrane potential oscillations underlying arterial spasm. Smooth muscle cell membrane potential (Em) and tension were measured simultaneously in rat middle cerebral artery. NO synthase blockade caused temporally coupled depolarizing oscillations in cerebrovascular Em with associated vasoconstriction. Both events were accentuated by block of smooth muscle BKCa. Block of T-type channels or inhibition of Na+/K+-ATPase abolished the oscillations in Em and reduced vasoconstriction. Oscillations in Em were either attenuated or accentuated by reducing [Ca2+]o or block of KV, respectively. TRAM-34 attenuated oscillations in both Em and tone, apparently independent of effects against KCa3.1. Thus, rapid depolarizing oscillations in Em and tone observed after endothelial function has been disrupted reflect input from T-type calcium channels in addition to L-type channels, while other depolarizing currents appear to be unimportant. These data suggest that combined block of T and L-type channels may represent an effective approach to reverse cerebral vasospasm.
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Affiliation(s)
- A J McNeish
- Department of Pharmacy and Pharmacology, University of Bath, Bath, United Kingdom
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