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Ramírez-Rodríguez Y, Espinosa-Tanguma R, Valle-Aguilera JR, Rodríguez-Menchaca AA, Saderi N, Salgado-Delgado R, Bautista E, Garcés L, Ramírez V, Robledo-Márquez K, Riego-Ruiz L, Trujillo J. Vasorelaxant Effect and Blood Pressure Reduction Potential of Pitaya Juice Concentrate ( Stenocereus huastecorum) Associated with Calcium Channel Blockade. Foods 2024; 13:2631. [PMID: 39200558 PMCID: PMC11353776 DOI: 10.3390/foods13162631] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2024] [Revised: 08/14/2024] [Accepted: 08/19/2024] [Indexed: 09/02/2024] Open
Abstract
Arterial hypertension is a highly prevalent chronic disease worldwide, with several etiologies and treatments that may eventually have side effects or result in patients developing tolerance. There is growing interest in traditional medicine and functional foods to isolate biomolecules that could be useful as coadjuvants for treating several aliments. Pitaya, a desert fruit endemic in Mexico, is a rich source of bioactive molecules (betalains and phenolic compounds). In this work, the vasorelaxation properties of pitaya juice concentrate and fraction one were investigated using aortic and mesenteric rings from rats. The incubation of rings with pitaya juice concentrate or fraction one induced significant vasorelaxation, independent of the endothelium, and showed resistance to potassium channel blockers. This vasorelaxation was associated with the transmembrane influx of extracellular calcium through the vascular smooth muscle cells, with an inhibitory effect on the voltage-dependent calcium channel currents. Also, 400 mg/mL of pitaya juice concentrate in spontaneous hypertensive rats reduced their blood pressure for 48 h. Phytochemical analyses showed that the primary compounds in F1 were glycosidic in nature, and could be a complex mixture of disaccharides, dimeric disaccharides, or even tetrasaccharides. The glycosidic compounds found in F1 primarily contributed to vasodilatation, establishing a voltage-dependent calcium channel inhibition as a possible molecular target.
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Affiliation(s)
- Yadira Ramírez-Rodríguez
- División de Biología Molecular, Instituto Potosino de Investigación Científica y Tecnológica (IPICYT), San Luis Potosí 78216, Mexico; (Y.R.-R.); (E.B.); (K.R.-M.); (L.R.-R.)
| | - Ricardo Espinosa-Tanguma
- Facultad de Medicina, Departamento de Fisiología y Biofísica, Universidad Autónoma de San Luis Potosí (UASLP), San Luis Potosí 78210, Mexico; (R.E.-T.); (J.R.V.-A.); (A.A.R.-M.)
| | - Juan Roberto Valle-Aguilera
- Facultad de Medicina, Departamento de Fisiología y Biofísica, Universidad Autónoma de San Luis Potosí (UASLP), San Luis Potosí 78210, Mexico; (R.E.-T.); (J.R.V.-A.); (A.A.R.-M.)
| | - Aldo A. Rodríguez-Menchaca
- Facultad de Medicina, Departamento de Fisiología y Biofísica, Universidad Autónoma de San Luis Potosí (UASLP), San Luis Potosí 78210, Mexico; (R.E.-T.); (J.R.V.-A.); (A.A.R.-M.)
| | - Nadia Saderi
- Facultad de Ciencias, Universidad Autónoma de San Luis Potosí (UASLP), San Luis Potosí 78210, Mexico; (N.S.); (R.S.-D.)
| | - Roberto Salgado-Delgado
- Facultad de Ciencias, Universidad Autónoma de San Luis Potosí (UASLP), San Luis Potosí 78210, Mexico; (N.S.); (R.S.-D.)
| | - Elihú Bautista
- División de Biología Molecular, Instituto Potosino de Investigación Científica y Tecnológica (IPICYT), San Luis Potosí 78216, Mexico; (Y.R.-R.); (E.B.); (K.R.-M.); (L.R.-R.)
- Consejo Nacional de Humanidades, Ciencias y Tecnologías (CONAHCyT), Benito Juárez, Mexico City 03940, Mexico
| | - Luis Garcés
- División de Materiales Avanzados, Instituto Potosino de Investigación Científica y Tecnológica (DMA-IPICYT), San Luis Potosí 78216, Mexico;
| | - Victoria Ramírez
- Departamento de Cirugía Experimental, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan, Mexico City 14080, Mexico;
| | - Karina Robledo-Márquez
- División de Biología Molecular, Instituto Potosino de Investigación Científica y Tecnológica (IPICYT), San Luis Potosí 78216, Mexico; (Y.R.-R.); (E.B.); (K.R.-M.); (L.R.-R.)
| | - Lina Riego-Ruiz
- División de Biología Molecular, Instituto Potosino de Investigación Científica y Tecnológica (IPICYT), San Luis Potosí 78216, Mexico; (Y.R.-R.); (E.B.); (K.R.-M.); (L.R.-R.)
| | - Joyce Trujillo
- Consejo Nacional de Humanidades, Ciencias y Tecnologías (CONAHCyT), Benito Juárez, Mexico City 03940, Mexico
- División de Materiales Avanzados, Instituto Potosino de Investigación Científica y Tecnológica (DMA-IPICYT), San Luis Potosí 78216, Mexico;
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Sams A, Haanes KA, Holm A, Kazantzi S, Mikkelsen LF, Edvinsson L, Brain S, Sheykhzade M. Heterogeneous vasomotor responses in segments from Göttingen Minipigs coronary, cerebral, and mesenteric artery: A comparative study. Vascul Pharmacol 2023; 153:107231. [PMID: 37730143 DOI: 10.1016/j.vph.2023.107231] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 09/13/2023] [Accepted: 09/17/2023] [Indexed: 09/22/2023]
Abstract
Göttingen Minipigs (GM) are used as an important preclinical model for cardiovascular safety pharmacology and for evaluation of cardiovascular drug targets. To improve the translational value of the GM model, the current study represents a basic characterization of vascular responses to endothelial regulators and sympathetic, parasympathetic, and sensory neurotransmitters in different anatomical origins. The aim of the current comparative and descriptive study is to use myography to characterize the vasomotor responses of coronary artery isolated from GM and compare the responses to those obtained from parallel studies using cerebral and mesenteric arteries. The selected agonists for sympathetic (norepinephrine), parasympathetic (carbachol), sensory (calcitonin gene-related peptide, CGRP), and endothelial pathways (endothelin-1, ET-1, and bradykinin) were used for comparison. Further, the robust nature of the vasomotor responses was evaluated after 24 h of cold storage of vascular tissue mimicking the situation under which human biopsies are often kept before experiments or grafting is feasible. Results show that bradykinin and CGRP consistently dilated, and endothelin consistently contracted artery segments from coronary, cerebral, and mesenteric origin. By comparison, norepinephrine and carbachol, had responses that varied with the anatomical source of the tissues. To support the basic characterization of GM vasomotor responses, we demonstrated the presence of mRNA encoding selected vascular receptors (CGRP- and ETA-receptors) in fresh artery segments. In conclusion, the vasomotor responses of isolated coronary, cerebral, and mesenteric arteries to selected agonists of endothelial, sympathetic, parasympathetic, and sensory pathways are different and the phenotypes are similar to sporadic human findings.
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Affiliation(s)
- Anette Sams
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark; Department of Clinical Experimental Research, Rigshospitalet, Glostrup, Denmark; Epoqe Pharma, Ole Maaloes Vej 3, 2200 Copenhagen N, Denmark.
| | | | - Anja Holm
- Department of Clinical Experimental Research, Rigshospitalet, Glostrup, Denmark; Center for RNA Medicine, Department of Clinical Medicine, Aalborg University, Copenhagen, Denmark
| | - Spyridoula Kazantzi
- Department of Clinical Experimental Research, Rigshospitalet, Glostrup, Denmark
| | | | - Lars Edvinsson
- Department of Clinical Experimental Research, Rigshospitalet, Glostrup, Denmark
| | - Susan Brain
- Section of Vascular Biology & Inflammation, School of Cardiovascular Medicine & Research, BHF Centre of Excellence, King's College London, London, United Kingdom
| | - Majid Sheykhzade
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
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3
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Bentsen S, Sams A, Hasbak P, Edvinsson L, Kjaer A, Ripa RS. Myocardial perfusion recovery induced by an α-calcitonin gene-related peptide analogue. J Nucl Cardiol 2022; 29:2090-2099. [PMID: 34089154 PMCID: PMC9553834 DOI: 10.1007/s12350-021-02678-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 05/10/2021] [Indexed: 11/28/2022]
Abstract
BACKGROUND Endogenous calcitonin gene-related peptide (CGRP) induces cardioprotective effects through coronary vasodilation. However, the systemic administration of CGRP induces peripheral vasodilation and positive chronotropic and inotropic effects. This study aims to examine the net effect on coronary perfusion of the systemically administered α-calcitonin gene-related peptide analogue, SAX, in rats during myocardial infarction. METHODS Forty Sprague-Dawley rats underwent myocardial infarction. Following left anterior descending artery occlusion, [99mTc]Tc-sestamibi was administered to determine the myocardial perfusion before treatment. Twenty minutes, 24 and 48 h after [99mTc]Tc-sestamibi injection, the rats were treated with either SAX or placebo. Final infarct size was determined three weeks later by [99mTc]Tc-sestamibi SPECT/CT scan. RESULTS Thirty-one rats survived the surgery and 20 completed the follow-up SPECT/CT scan (SAX n = 12; Placebo n = 8). At baseline, there was no difference in size of perfusion defect between the groups (P = .88), but at follow-up the SAX group had improved myocardial recovery compared to the placebo group (P = .04), corresponding to a relative perfusion recovery of 55% in SAX-treated rats. CONCLUSION The CGRP analogue, SAX, has a cardioprotective effect in this rat model of myocardial infarction, improving myocardial perfusion recovery after chronic occlusion of the coronary artery.
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Affiliation(s)
- Simon Bentsen
- Department of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Rigshospitalet and University of Copenhagen, Copenhagen, Denmark.
| | - Anette Sams
- Department of Clinical Experimental Research, Glostrup Research Institute, Glostrup University Hospital, Nordstjernevej 42, 2600, Glostrup, Denmark
| | - Philip Hasbak
- Department of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Rigshospitalet and University of Copenhagen, Copenhagen, Denmark
| | - Lars Edvinsson
- Department of Clinical Experimental Research, Glostrup Research Institute, Glostrup University Hospital, Nordstjernevej 42, 2600, Glostrup, Denmark
| | - Andreas Kjaer
- Department of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Rigshospitalet and University of Copenhagen, Copenhagen, Denmark
| | - Rasmus S Ripa
- Department of Clinical Physiology, Nuclear Medicine & PET and Cluster for Molecular Imaging, Rigshospitalet and University of Copenhagen, Copenhagen, Denmark
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Sohn I, Sheykhzade M, Edvinsson L, Sams A. The effects of CGRP in vascular tissue - Classical vasodilation, shadowed effects and systemic dilemmas. Eur J Pharmacol 2020; 881:173205. [PMID: 32442540 DOI: 10.1016/j.ejphar.2020.173205] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Revised: 04/29/2020] [Accepted: 05/14/2020] [Indexed: 02/02/2023]
Abstract
Vascular tissue consists of endothelial cells, vasoactive smooth muscle cells and perivascular nerves. The perivascular sensory neuropeptide CGRP has demonstrated potent vasodilatory effects in any arterial vasculature examined so far, and a local protective CGRP-circuit of sensory nerve terminal CGRP release and smooth muscle cell CGRP action is evident. The significant vasodilatory effect has shadowed multiple other effects of CGRP in the vascular tissue and we therefore thoroughly review vascular actions of CGRP on endothelial cells, vascular smooth muscle cells and perivascular nerve terminals. The actions beyond vasodilation includes neuronal re-uptake and neuromodulation, angiogenic, proliferative and antiproliferative, pro- and anti-inflammatory actions which vary depending on the target cell and anatomical location. In addition to the classical perivascular nerve-smooth muscle CGRP circuit, we review existing evidence for a shadowed endothelial autocrine pathway for CGRP. Finally, we discuss the impact of local and systemic actions of CGRP in vascular regulation and protection from hypertensive and ischemic heart conditions with special focus on therapeutic CGRP agonists and antagonists.
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Affiliation(s)
- Iben Sohn
- Department of Clinical Experimental Research, Glostrup Research Institute, Rigshospitalet Glostrup, Nordstjernevej 42, DK-2600, Glostrup, Denmark
| | - Majid Sheykhzade
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100, Copenhagen Oe, Denmark
| | - Lars Edvinsson
- Department of Clinical Experimental Research, Glostrup Research Institute, Rigshospitalet Glostrup, Nordstjernevej 42, DK-2600, Glostrup, Denmark; Department of Clinical Sciences, Division of Experimental Vascular Research, Lund University, Lund, Sweden
| | - Anette Sams
- Department of Clinical Experimental Research, Glostrup Research Institute, Rigshospitalet Glostrup, Nordstjernevej 42, DK-2600, Glostrup, Denmark.
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Manoury B, Idres S, Leblais V, Fischmeister R. Ion channels as effectors of cyclic nucleotide pathways: Functional relevance for arterial tone regulation. Pharmacol Ther 2020; 209:107499. [PMID: 32068004 DOI: 10.1016/j.pharmthera.2020.107499] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2018] [Accepted: 02/05/2020] [Indexed: 02/07/2023]
Abstract
Numerous mediators and drugs regulate blood flow or arterial pressure by acting on vascular tone, involving cyclic nucleotide intracellular pathways. These signals lead to regulation of several cellular effectors, including ion channels that tune cell membrane potential, Ca2+ influx and vascular tone. The characterization of these vasocontrictive or vasodilating mechanisms has grown in complexity due to i) the variety of ion channels that are expressed in both vascular endothelial and smooth muscle cells, ii) the heterogeneity of responses among the various vascular beds, and iii) the number of molecular mechanisms involved in cyclic nucleotide signalling in health and disease. This review synthesizes key data from literature that highlight ion channels as physiologically relevant effectors of cyclic nucleotide pathways in the vasculature, including the characterization of the molecular mechanisms involved. In smooth muscle cells, cation influx or chloride efflux through ion channels are associated with vasoconstriction, whereas K+ efflux repolarizes the cell membrane potential and mediates vasodilatation. Both categories of ion currents are under the influence of cAMP and cGMP pathways. Evidence that some ion channels are influenced by CN signalling in endothelial cells will also be presented. Emphasis will also be put on recent data touching a variety of determinants such as phosphodiesterases, EPAC and kinase anchoring, that complicate or even challenge former paradigms.
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Affiliation(s)
- Boris Manoury
- Inserm, Umr-S 1180, Université Paris-Saclay, Châtenay-Malabry, France.
| | - Sarah Idres
- Inserm, Umr-S 1180, Université Paris-Saclay, Châtenay-Malabry, France
| | - Véronique Leblais
- Inserm, Umr-S 1180, Université Paris-Saclay, Châtenay-Malabry, France
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Kristiansen SB, Sheykhzade M, Edvinsson L, Haanes KA. Changes in vasodilation following myocardial ischemia/reperfusion in rats. Nitric Oxide 2017; 70:68-75. [PMID: 28919322 DOI: 10.1016/j.niox.2017.09.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2017] [Revised: 08/01/2017] [Accepted: 09/12/2017] [Indexed: 01/08/2023]
Abstract
BACKGROUND Blockage of a coronary artery, usually caused by arteriosclerosis, can lead to life threatening acute myocardial infarction. Opening with PCI (percutaneous coronary intervention), may be lifesaving, but reperfusion might exacerbate the cellular damage, and changes in the endothelium are believed to be involved in this worsened outcome. AIM The aim of the present study was to compare endothelial dependent and independent vasodilatory effect after experimental myocardial ischemia/reperfusion (I/R). METHODS A well-established rat model of myocardial ischemia with 24 h of reperfusion was applied, followed by a study in a wire myograph. RESULTS Endothelial NO dependent relaxation in response to carbachol, was sensitive to arterial depolarization, and was unaffected by I/R. In contrast, endothelial NO dependent ADPβS signalling, which was not sensitive to arterial depolarization, was significantly reduced after I/R. Following I/R, an H2O2 dependent EDH induced dilation appears in response to both of the above agonists. In addition, calcitonin gene-related peptide (CGRP) induced vasodilation was reduced. CONCLUSION These data show that NO dependent ADPβS induced dilation is reduced after I/R. However, there is some compensation by released H2O2 causing an EDH. Combined with a loss of maximal dilation in response to CGRP, the reduced vasodilation could be an important factor in understanding the exacerbated damage after I/R.
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Affiliation(s)
- Sarah Brøgger Kristiansen
- Department of Clinical Experimental Research, Glostrup Research Institute, Copenhagen University Hospital, Rigshospitalet-Glostrup, Denmark; Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Majid Sheykhzade
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
| | - Lars Edvinsson
- Department of Clinical Experimental Research, Glostrup Research Institute, Copenhagen University Hospital, Rigshospitalet-Glostrup, Denmark
| | - Kristian Agmund Haanes
- Department of Clinical Experimental Research, Glostrup Research Institute, Copenhagen University Hospital, Rigshospitalet-Glostrup, Denmark.
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Vanheel B. Calcitonin gene-related powerpeptide and its puzzling receptor. Acta Physiol (Oxf) 2014; 210:710-3. [PMID: 24495305 DOI: 10.1111/apha.12245] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- B. Vanheel
- Department of Basic Medical Sciences; Division of Physiology; Ghent University; Ghent Belgium
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8
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Influence of methanandamide and CGRP on potassium currents in smooth muscle cells of small mesenteric arteries. Pflugers Arch 2012; 463:669-77. [PMID: 22415212 DOI: 10.1007/s00424-012-1083-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2011] [Revised: 02/02/2012] [Accepted: 02/03/2012] [Indexed: 01/26/2023]
Abstract
Cannabinoids have potent vasodilatory actions in a variety of vascular preparations. Their mechanism of action, however, is complex. Apart from acting on vascular smooth muscle or endothelial cannabinoid receptors, several studies point to the activation of type 1 vanilloid (TRPV1) receptors on primary afferent perivascular nerves, stimulating the release of calcitonin gene-related peptide (CGRP). In the present study, the direct influence of the cannabinoid methanandamide and the neuropeptide CGRP on the membrane potassium ion (K(+)) currents of rat mesenteric myocytes was explored. Methanandamide (10 μM) decreased outward K(+) currents, an effect similar to that observed in smooth muscle cells from the rat aorta. Conversely, CGRP (10 nM) significantly increased whole-cell K(+) currents and this effect was abolished by preexposure to tetraethylammonium chloride (1 mM) or iberiotoxin (100 nM), inhibitors of large-conductance calcium-dependent K (BK(Ca)) channels but not by glibenclamide (10 μM), an inhibitor of ATP-dependent K channels. In the presence of the CGRP receptor antagonist CGRP(8-37) (100 nM), the adenylyl cyclase inhibitor SQ22536 (100 μM), or the protein kinase A inhibitor Rp-cAMPS (10 μM), CGRP had no effect. These findings show that methanandamide does not increase membrane K(+) currents in smooth muscle cells of small mesenteric arteries, supporting an indirect mechanism for the reported hyperpolarizing influence in this vessel. Moreover, CGRP acts directly on these smooth muscle cells by increasing BK(Ca) channel activity in a CGRP receptor and cyclic adenosine monophosphate-dependent way. Collectively, these data indicate that methanandamide relaxes and hyperpolarizes intact mesenteric vessels by releasing CGRP from perivascular nerves.
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Villalba N, Martínez P, Bríones AM, Sánchez A, Salaíces M, García-Sacristán A, Hernández M, Benedito S, Prieto D. Differential structural and functional changes in penile and coronary arteries from obese Zucker rats. Am J Physiol Heart Circ Physiol 2009; 297:H696-707. [PMID: 19542483 DOI: 10.1152/ajpheart.01308.2008] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Erectile dysfunction frequently coexists with coronary artery disease and has been proposed as a potential marker for silent coronary artery disease in type 2 diabetes. In the present study, we comparatively assessed the structural and functional changes of both penile arteries (PAs) and coronary arteries (CAs) from a prediabetic animal model. PAs and CAs from 17- to 18-wk-old obese Zucker rats (OZRs) and from their control counterparts [lean Zucker rats (LZRs)] were mounted in microvascular myographs to evaluate vascular function, and stained arteries were subjected to morphometric analysis. Endothelial nitric oxide (NO) synthase (eNOS) protein expression was also assessed. The internal diameter was reduced and the wall-to-lumen ratio was increased in PAs from OZRs, but structure was preserved in CAs. ACh-elicited relaxations were severely impaired in PAs but not in CAs from OZRs, although eNOS expression was unaltered. Contractions to norepinephrine and 5-HT were significantly enhanced in both PAs and CAs, respectively, from OZRs. Blockade of NOS abolished endothelium-dependent relaxations in PAs and CAs and potentiated norepinephrine and 5-HT contractions in arteries from LZRs but not from OZRs. The vasodilator response to the phosphodiesterase 5 inhibitor sildenafil was reduced in both PAs and CAs from OZRs. Pretreatment with SOD reduced the enhanced vasoconstriction in both PAs and CAs from OZRs but did not restore ACh-induced relaxations in PAs. In conclusion, the present results demonstrate vascular inward remodeling in PAs and a differential impairment of endothelial relaxant responses in PAs and CAs from insulin-resistant OZRs. Enhanced superoxide production and reduced basal NO activity seem to underlie the augmented vasoconstriction in both PAs and CAs. The severity of the structural and functional abnormalities in PAs might anticipate the vascular dysfunction of the more preserved coronary vascular bed.
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Affiliation(s)
- Nuria Villalba
- Department of Physiology, Faculty of Pharmacy, Faculty of Veterinary Sciences, Universidad Complutense, Madrid, Spain
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Pagán RM, Martínez AC, Martínez MP, Hernández M, García-Sacristán A, Correa C, Prieto D, Benedito S. Endothelial and potassium channel dependent modulation of noradrenergic vasoconstriction in the pig radial artery. Eur J Pharmacol 2009; 616:166-74. [PMID: 19527707 DOI: 10.1016/j.ejphar.2009.06.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2009] [Revised: 05/18/2009] [Accepted: 06/03/2009] [Indexed: 11/28/2022]
Abstract
The localisation and function of noradrenergic perivascular innervation of the radial artery were examined in a porcine model. Through immunohistochemical techniques, we explored the possible existence of dopamine beta-hydroxylase and choline-acetyltransferase in the nerve fibres supplying the radial artery. Arterial rings suspended in organ baths were used to isometrically record tension in functional tests designed to determine the vasoconstriction response to electrical field stimulation (EFS) or exogenous noradrenaline. Morphological studies revealed the presence of noradrenergic, but not cholinergic, nerve fibres in the tunica adventitia and adventitia-media boundary of the artery wall. EFS-elicited frequency-dependent contractions (EF(50)=3.37+/-0.19 Hz and E(max)=87.7+/-3.8%; n=47) were abolished by tetrodotoxin. The contractile effect was markedly reduced by guanethidine, phentolamine and prazosin and slightly inhibited by rauwolscine, but unaltered by propranolol, atropine, bosentan or capsaicine. Endothelium removal increased EFS-evoked contractions but the addition of L-NOArg, ODQ or indomethacin had no effect. Pre-incubation with tetraethylammonium and 4-aminopyridine, but not glibenclamide, enhanced these neurogenic responses. SOD and apocynin reduced EFS-elicited responses at low frequencies. Exposure of the arterial rings to the same agents did not affect the noradrenaline concentration-response curves except for the alpha-adrenoceptor antagonists. These results led to the conclusions that neurogenic contractions in the pig radial artery are predominantly mediated by noradrenaline released from periarterial adrenergic nerves. This neurogenic vasoconstriction is modulated by a non-NO, non-prostanoid endothelium-dependent relaxing factor and by Ca(2+)-activated and voltage-dependent K(+) channels.
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Affiliation(s)
- Rosa María Pagán
- Department of Physiology, Faculty of Pharmacy, Universidad Complutense de Madrid, Madrid, Spain
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11
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Garcha RS, Hughes AD. CNP, but not ANP or BNP, relax human isolated subcutaneous resistance arteries by an action involving cyclic GMP and BKCa channels. J Renin Angiotensin Aldosterone Syst 2007; 7:87-91. [PMID: 17083062 DOI: 10.3317/jraas.2006.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Natriuretic peptides play an important role in sodium regulation and blood pressure (BP) control. We examined the effects of atrial natriuetic peptide (ANP), brain natriuretic peptide (BNP) and C-type natriuretic peptide (CNP) on human isolated resistance arteries and the mechanisms involved in vasorelaxation. Human subcutaneous resistance arteries were mounted in an isometric myograph and contracted with phenylephrine. CNP, but not ANP or BNP, relaxed arteries in a concentration dependent manner. The action of CNP was unaffected by removal of the endothelium, inhibition of nitric oxide synthase by NG-monomethyl-Larginine or inhibition of soluble guanylate cyclase by 1H-[1,2,4] oxadiazolo [4,3-alpha] quinoxalin-1-one. Blockade of cyclic GMPdependent kinase by 8- bromoguanosine- 3, 5- cyclic monophosphorothioate, Rp-isomer (Rp-8-Br-cGMPS) inhibited CNP relaxation. CNP relaxation was also inhibited by high potassium or iberiotoxin, indicating that it was due to opening of BKCa channels. Omapatrilat, a vasopeptidase inhibitor of neutral endopeptidase and angiotensin-converting enzyme, enhanced the effect of CNP and inhibited responses to Ang I. In summary, CNP, but not ANP or BNP, relaxes human resistance arteries by activating cyclic GMP-dependent kinase and BKCa. The effects of CNP are enhanced by vasopeptidase inhibition and this may contribute to the vasodilator effects of these agents in vivo. Since CNP is widely present in endothelium it may play a role in the regulation of peripheral resistance in man in physiological and pathological circumstances.
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Affiliation(s)
- Robinder S Garcha
- Clinical Pharmacology, National Heart & Lung Institute, London, W2 1NY, UK
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Hasbak P, Eskesen K, Schifter S, Edvinsson L. Increased alphaCGRP potency and CGRP-receptor antagonist affinity in isolated hypoxic porcine intramyocardial arteries. Br J Pharmacol 2005; 145:646-55. [PMID: 15834440 PMCID: PMC1576180 DOI: 10.1038/sj.bjp.0706232] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
1. This study describes the effects of hypoxia on relaxing responses and cAMP production induced by the known vasodilator peptides: alphaCGRP, amylin (AMY) and adrenomedullin (AM) on isolated pig coronary arteries in vitro. 2. Hypoxic incubation increased the vasorelaxant effect of alphaCGRP (four-fold; P<0.05), AMY (3.2-fold; P<0.05), but not significantly for AM (two-fold; NS). 3. Whereas hypoxia had no effect on arterial cAMP levels, it significantly potentiated the production of cAMP stimulated of alphaCGRP and AMY, but not of AM. 4. The antagonist alphaCGRP(8-37) also exerted an increased effect in hypoxia. The Schild plot-derived pK(B) values revealed an increase in the apparent affinity of the antagonist for the CGRP(1) receptor from 7.0 to 7.2 under control conditions versus 8.0 in hypoxia. 5. Removal of endothelium, peptidase inhibitors, preincubation with the adenosine A(2A) receptor antagonist CSC (10(-3) M), the ATP-sensitive K-channel inhibitor glibenclamide (10(-5) M), the cyclooxygenase inhibitor indomethacin (10(-3) M) or NG-monomethyl-L-arginine (10(-4) M) had no effect on the alphaCGRP-induced vasorelaxation in hypoxia; neither did hypoxia influence the levels of CGRP and AM receptor mRNA. 6. We conclude that hypoxic incubation increases the relaxation and cAMP production induced by alphaCGRP and AMY in rings of porcine coronary arteries in vitro. A concomitant release of adenosine, a cyclooxygenase product, an endothelium-derived substance, activation of vascular ATP-sensitive K-channels, peptidase inhibitors or changes in CGRP and AM receptor mRNA cannot account for the changes observed in hypoxia. Moreover, alphaCGRP(8-37) showed increased affinity at the CGRP(1) receptor during hypoxia, possibly due to a conformational change at the CGRP(1) receptor site.
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Affiliation(s)
- Philip Hasbak
- Department of Clinical Experimental Research, University Hospital of Glostrup, Glostrup, Denmark.
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Sheykhzade M, Berg Nyborg NC. Homologous desensitization of calcitonin gene-related peptide-induced relaxation in rat intramural coronary arteries. Eur J Pharmacol 2004; 484:91-101. [PMID: 14729386 DOI: 10.1016/j.ejphar.2003.10.052] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We investigated the type of desensitization of calcitonin gene-related peptide (CGRP)-induced responses in rat isolated intramural coronary arteries using isometric myograph and FURA-2 technique. In coronary arteries precontracted with 9,11-dideoxy-11alpha,9alpha-epoxymethanoprostaglandin F2alpha (U46619), development of tachyphylaxis to CGRP is characterized by significant attenuation of CGRP-induced maximal reduction in the tension and [Ca2+](i) during the second CGRP concentration-response curve; however, there was no further reduction in the CGRP-induced maximum relaxation during the third CGRP concentration-response curve. There was no sign of tachyphylaxis to CGRP when CGRP concentration-response curves were recorded in 36 mM K+-depolarized coronary arteries contrary to the results obtained in 300 nM U46619-precontracted coronary arteries. Preincubation with colchicine did not prevent the development of tachyphylaxis to CGRP in U46619-precontracted coronary arteries, indicating no role for endocytosis. Development of tachyphylaxis to CGRP was completely abolished by preincubating the coronary arteries with 1 microM RO 31-8220, indicating a role for protein kinases. Pre-exposure of the coronary arteries to isoprenaline or forskolin did not attenuate the CGRP-induced relaxation in these vessels, indicating that the cAMP-protein kinase A (PKA) pathway is not involved. Like CGRP, the coronary arteries developed tachyphylaxis toward isoprenaline during the second exposure. However, there was no sign of tachyphylaxis to either forskolin or dibutyryl cAMP (dbcAMP) during the second exposure. In conclusion, these results suggest that development of tachyphylaxis to CGRP in U46619-precontracted coronary is related to CGRP receptor-mediated activation of protein kinase.
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Affiliation(s)
- Majid Sheykhzade
- Department of Pharmacology, The Danish University of Pharmaceutical Sciences, Universitetsparken 2, DK-2100 Ø, Copenhagen, Denmark.
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14
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Jansen-Olesen I, Kaarill L, Edvinsson L. Characterization of CGRP(1) receptors in the guinea pig basilar artery. Eur J Pharmacol 2001; 414:249-58. [PMID: 11239926 DOI: 10.1016/s0014-2999(01)00760-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The purpose of the present study was to characterise receptors mediating calcitonin gene-related peptide (CGRP)-induced relaxation of guinea pig basilar artery. This was done by investigating vasomotor responses in vitro and performing autoradiographic binding studies. We also intended to study the importance of an intact endothelium. Agonist studies showed that peptides of the CGRP family induced relaxation of the guinea pig basilar artery with the following order of potency: human beta-CGRP=human alpha-CGRP>>adrenomedullin=[acetamidomethyl-Cys(2,7)]alpha-human CGRP ([Cys(ACM)(2,7)]CGRP)=amylin. These data are in concord with those of the autoradiographic binding studies that showed displacement of [125I] human alpha-CGRP binding with the following order of potency: human alpha-CGRP=human beta-CGRP>>adrenomedullin=human alpha-CGRP-(8-37)>>Cys(ACM)(2,7)]CGRP. In blockade experiments, the relaxant responses to human alpha- and human beta-CGRP were competitively blocked by the CGRP(1) receptor antagonist human alpha-CGRP-(8-37), while those of adrenomedullin and amylin were blocked non-competitively. In order to examine whether amylin induced relaxation via amylin or CGRP receptors, we studied the antagonistic effect of amylin-(8-37) on the weak relaxant response to amylin and found that it was not blocked by amylin-(8-37). These findings, together with the finding that the CGRP(2) receptor agonist [Cys(ACM)(2,7)]CGRP only induced a weak relaxation in the highest concentrations examined, suggest that the CGRP family of peptides mediate relaxation by CGRP(1)-type receptors. Removal of the endothelium, the addition of N(G)-nitro-L-arginine methyl ester (L-NAME), methylene blue or indomethacin did not affect the concentration-response curves of the CGRP analogues, neither in the presence nor in the absence of human CGRP-(8-37). The study shows the presence of a relaxant CGRP(1) receptor on the smooth muscle cells of guinea pig basilar artery. Various endothelial factors did not influence relaxant responses.
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Affiliation(s)
- I Jansen-Olesen
- Department of Pharmacology, The Royal Danish School of Pharmacy, Universitetsparken 2, 2100 Copenhagen, Denmark.
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15
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Sheykhzade M, Berg Nyborg NC. Mechanism of CGRP-induced relaxation in rat intramural coronary arteries. Br J Pharmacol 2001; 132:1235-46. [PMID: 11250874 PMCID: PMC1572669 DOI: 10.1038/sj.bjp.0703936] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
1. This study investigates the mechanism of CGRP-induced relaxation in intramural coronary arteries by determining the effect of CGRP on cytosolic Ca(2+) concentration ([Ca(2+)](i)) using FURA-2 technique. 2. CGRP concentration-dependently (10 pM - 100 nM) decreased the [Ca(2+)](i) and tension of coronary arteries precontracted with either U46619 or BAY K 8644, and also of resting coronary arteries in PSS. In 36 mM K(+)-depolarized arteries, CGRP reduced only the tension without affecting the [Ca(2+)](i). 3. In 300 nM U46619- precontracted arteries, pretreatment with 10 microM thapsigargin significantly (P<0.05) attenuated the CGRP-induced reduction in the tension (but not [Ca(2+)](i)). 4. In 300 nM U46619-precontracted arteries, pretreatment with either 100 nM charybdotoxin or 100 nM iberiotoxin or 10 nM felodipine significantly (P<0.05) attenuated the CGRP-induced reduction in both [Ca(2+)](i) and tension. In contrast, 1 microM glibenclamide did not affect the CGRP-induced responses in these coronary arteries. 5. In resting coronary arteries, only pretreatment with the combination of 1 microM glibenclamide and 100 nM charybdotoxin attenuated the CGRP-induced decrease in the [Ca(2+)](i) and tension, suggesting a different mechanism of action for CGRP in resting coronary arteries. 6. We conclude that CGRP relaxes precontracted rat coronary arteries via three mechanisms: (1) a decrease in [Ca(2+)](i) by inhibiting the Ca(2+) influx through membrane hyperpolarization mediated partly by activation of the large conductance Ca(2+)-activated potassium channels, (2) a decrease in [Ca(2+)](i) presumably by sequestrating cytosolic Ca(2+) into thapsigargin-sensitive Ca(2+) storage sites and (3) a decrease in the Ca(2+)-sensitivity of the contractile apparatus. In resting coronary arteries, however, there seems to be an interplay between different types of K(+) channels.
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Affiliation(s)
- M Sheykhzade
- Department of Pharmacology, The Royal Danish School of Pharmacy, Universitetsparken 2, DK-2100 Copenhagen, Denmark.
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16
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Lam FF. Pharmacologic characterization of receptor types mediating coronary vasodilator actions of sensory neuropeptides in the guinea pig. J Cardiovasc Pharmacol 2000; 35:646-52. [PMID: 10774797 DOI: 10.1097/00005344-200004000-00019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The receptor types mediating sensory neuropeptide-induced coronary vasodilatation were elucidated on isolated guinea pig hearts perfused with isotonic buffer containing 20 mM KCl. Substance P and the selective neurokinin-1 (NK1) receptor agonist [Sar9, Met(O2)11]-substance P produced dose-dependent reductions in perfusion pressure, but the selective NK2 receptor agonist [Nle10]-neurokinin A4-10 and the selective NK3 receptor agonist [MePhe7]-neurokinin B produced no change. The vasorelaxant effects of substance P and the NK1 receptor agonist were abolished by the selective NK1 receptor antagonist FK888 (N2-[(4R)-4-hydroxy-1-(1-methyl-1H-indol-3-yl)carbonyl-L-prolyl]-N-methy l-N-phenylmethyl-3-(2-naphthyl)-L-alaninamide), whereas the selective NK2 receptor antagonist SR48968 ((S)-N-methyl-N-[4-acetylamino-4-phenylpiperidino)-2-(3,4-dichlorophenyl )-butyl] benzamide) and the selective NK3 receptor antagonist SR142801 ((S)-(N)-( 1-(3-(1-benzoyl-3-(3,4-dichlorophenyl)piperidin-3-yl)propyl)4-p henylpiperidin-4-yl)-N-methylacetamide) produced partial inhibition on their responses. Calcitonin gene-related peptide (CGRP) produced dose-dependent vasodilatation on the guinea pig coronary blood vessels, which was significantly (p = 0.0067) inhibited by the selective CGRP1 receptor antagonist hCGRP8-37. The selective CGRP2 receptor agonist [Cys(acetomethoxy)2,7]CGRP had no effect on perfusion pressure. These results demonstrate that the sensory neuropeptides substance P and CGRP are effective vasodilators of the guinea pig coronary vascular bed. The receptor types mediating their vasorelaxant effects were identified to be the NK1 receptors and CGRP1 receptors, respectively.
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Affiliation(s)
- F F Lam
- Department of Pharmacology, The Chinese University of Hong Kong, Shatin, New Territories, SAR, China.
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17
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Sheykhzade M, Dalsgaard GT, Johansen T, Nyborg NC. The effect of long-term streptozotocin-induced diabetes on contractile and relaxation responses of coronary arteries: selective attenuation of CGRP-induced relaxations. Br J Pharmacol 2000; 129:1212-8. [PMID: 10725270 PMCID: PMC1571940 DOI: 10.1038/sj.bjp.0703159] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. This study investigates the effect of partially metabolic controlled long-term (34 weeks) streptozotocin (STZ)-induced diabetes on relaxation and contractile responses of isolated coronary arteries to seven different vasoactive agents. 2. The average fasting and non-fasting blood glucose concentrations (mM) were significantly elevated in STZ-induced diabetic rats (P<0.0001; 10.4+/-0.4 and 16. 6+/-1.1, n=15) compared to those (4.3+/-0.03 and 4.7+/-0.18, n=11) in age-matched controls. The level of glycated haemoglobin (HbA(1)) was also significantly (P<0.0001) increased in STZ-induced diabetic rats. In STZ-induced diabetic rats, the HbA(1) levels were significantly correlated with the non-fasting blood glucose concentrations (r=0.76; P=0.003; n=13). In both groups, there was no significant correlation between the HbA(1) levels and maximal responses or sensitivities to the vasoactive agents. 3. The maximal relaxation induced by rat-alphacalcitonin gene-related peptide (rat-alphaCGRP) was significantly attenuated in the coronary arteries of STZ-induced diabetic rats (P<0.05; 40+/-7%, n=15) compared to that in age-matched controls (63+/-3%, n=11). However, there was no significant difference in the sensitivity to rat-alphaCGRP between the two groups. 4. There was no significant difference in either maximal response or sensitivity to any of the six other vasoactive agents between STZ- induced diabetic rats (n=15) and age-matched controls (n=11). 5. Our results show that partially metabolic controlled long-term (34 weeks) STZ-induced diabetes causes a selective depression of rat-alphaCGRP-induced relaxation in the intramural coronary arteries of Wistar rats.
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Affiliation(s)
- M Sheykhzade
- Department of Pharmacology, The Royal Danish School of Pharmacy, Universitetsparken 2, DK-2100 Copenhagen O, Denmark.
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18
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Zanesco A, Costa SK, Riado SR, Nathan LP, de Oliveira CF, De Luca IM, Antunes E, De Nucci G. Modulation of coronary flow and cardiomyocyte size by sensory fibers. Hypertension 1999; 34:790-4. [PMID: 10523362 DOI: 10.1161/01.hyp.34.4.790] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cardiac tissue is densely innervated by sensory neurons that are believed to play important modulatory roles in cardiac functions. In this study, pretreatment of neonate rats with capsaicin was performed. In adult rats, cardiomyocyte size and amount of fibrous tissue in left ventricles as well as in vitro coronary flow were evaluated. The chronotropic and inotropic responses to beta-adrenoceptor agonists (norepinephrine and isoproterenol), muscarinic agonists (carbachol and pilocarpine), and calcitonin gene-related peptide (CGRP) were also investigated with the use of the isolated right atria preparation. Capsaicin pretreatment significantly (P<0.05) reduced both basal coronary flow (18% reduction) and cardiomyocyte size (34% reduction) without affecting the amount of fibrous tissues in the left ventricles. The positive inotropic and chronotropic effects in response to norepinephrine in the isolated rat heart did not significantly differ between control and capsaicin-treated rats. Similarly, the positive chronotropic effects in response to norepinephrine, isoproterenol, and CGRP as well as the negative chronotropic responses to carbachol and pilocarpine in the isolated right atria were not affected by capsaicin pretreatment. Our data are consistent with the suggestion that reductions of both basal coronary flow and cardiomyocyte size seen in hearts from capsaicin-pretreated rats may be consequences of CGRP depletion. The cardiomyocyte size reduction produced by capsaicin treatment may be related to a modulatory role of CGRP as a growth factor.
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Affiliation(s)
- A Zanesco
- Department of Physical Education, Biosciences Institute, Paulista State University, Rio Claro (SP), Brazil.
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19
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Lu LF, Fiscus RR. Nitric oxide donors enhance calcitonin gene-related peptide-induced elevations of cyclic AMP in vascular smooth muscle cells. Eur J Pharmacol 1999; 376:307-14. [PMID: 10448892 DOI: 10.1016/s0014-2999(99)00370-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Vasorelaxant effects of calcitonin gene-related peptide (CGRP) are dependent on endothelium-derived nitric oxide (NO) in some arteries. The mechanism involved is still not clear. In the present study, we used NO donors (sodium nitroprusside (SNP) and 6-(2-hydroxy-1-methyl-2-nitrisohydrazino)-N-methyl-1-hyxanamine (NOC-9)), cyclic GMP elevator (brain natriuretic peptide (BNP)) and a selective type III (cyclic GMP-inhibited) phosphodiesterase (PDE) inhibitor 5-(4-acetamidophenyl)pyrazin-2(1H)-one (SK&F94120) to investigate involvement of NO, cyclic GMP and type III PDE in CGRP-induced accumulation of cyclic AMP in cultured rat aortic smooth muscle cells. SNP (10 microM), NOC-9 (10 microM) and BNP (1 microM) all increased intracellular cyclic GMP to similar levels (2- to 2.5-fold above basal) and caused significant enhancement of CGRP (10 nM)-induced cyclic AMP accumulation similar to that caused by 10 microM SK&F 94120. The data are therefore consistent with our hypothesis that the mechanism of endothelium-dependent vasorelaxation effect of CGRP involves cyclic GMP-mediated inhibition of type III PDE and subsequent accumulation of cyclic AMP in smooth muscle cells.
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Affiliation(s)
- L F Lu
- Department of Physiology, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories
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20
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Pickkers P, Garcha RS, Schachter M, Smits P, Hughes AD. Inhibition of carbonic anhydrase accounts for the direct vascular effects of hydrochlorothiazide. Hypertension 1999; 33:1043-8. [PMID: 10205245 DOI: 10.1161/01.hyp.33.4.1043] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Hydrochlorothiazide has been shown to exert direct vasodilator effects by activation of calcium-activated potassium (KCa) channels in human and guinea pig isolated resistance arteries. Since hydrochlorothiazide binds to and inhibits the enzyme carbonic anhydrase and because KCa channel activation is pH sensitive, we investigated the role of intracellular and extracellular carbonic anhydrase in the vascular effects of thiazide diuretics. Small arteries were isolated from guinea pig mesentery and studied by use of a microvascular myograph technique. In some experiments, tone and intracellular pH (pHi) were measured simultaneously with 2', 7'-bis(2-carboxyethyl)-5(6)'-carboxyfluorescein (BCECF-AM). Bendroflumethiazide, a thiazide diuretic with minimal inhibitory effects on carbonic anhydrase, had little effect on noradrenaline-induced tone (16+/-8% relaxation) compared with hydrochlorothiazide (74+/-12% relaxation). In contrast to hydrochlorothiazide, the action of bendroflumethiazide was unaffected by 100 nmol/L charybdotoxin, a selective blocker of KCa channels. All inhibitors of carbonic anhydrase relaxed noradrenaline-induced tone in a concentration-dependent manner, and this effect was blocked by charybdotoxin. Hydrochlorothiazide and the inhibitors of carbonic anhydrase failed to relax tone induced by a depolarizing potassium solution. Acetazolamide and hydrochlorothiazide increased pHi by 0.27+/-0.07 and 0.21+/-0.04, respectively, whereas bendroflumethiazide had a much smaller effect: 0.06+/-0.03. The rise in pHi induced by any agent was not inhibited by charybdotoxin. The vasorelaxant effect of hydrochlorothiazide is shared by other inhibitors of carbonic anhydrase. Inhibitors of carbonic anhydrase, but not bendroflumethiazide, cause intracellular alkalinization, which is associated with KCa channel opening. These data suggest that the vasodilator effect of thiazide diuretics results primarily from inhibition of vascular smooth muscle cell carbonic anhydrase, which results in a rise in pHI, leading to KCa channel activation and vasorelaxation.
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Affiliation(s)
- P Pickkers
- Department of Pharmacology, University Hospital Nijmegen, Nijmegen, The Netherlands
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21
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Kress M, Guthmann C, Averbeck B, Reeh PW. Calcitonin gene-related peptide and prostaglandin E2 but not substance P release induced by antidromic nerve stimulation from rat skin in vitro. Neuroscience 1999; 89:303-10. [PMID: 10051237 DOI: 10.1016/s0306-4522(98)00280-2] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The liberation of calcitonin gene-related peptide from rat skin in vitro induced by antidromic electrical stimulation of unmyelinated units is demonstrated. Prostaglandin E2 was released concomitantly during C-fiber stimulation. A dose-dependent increase in prostaglandin E2 content of the eluate was also observed in response to stimulation with substance P (10(-7) to 10(-5) M) and calcitonin gene-related peptide (10(-6) and 10(-5) M). In contrast, prostaglandin E2 did not induce measurable release of neuropeptides. The amount of calcitonin gene-related peptide released during suprathreshold electrical stimulation increased with pulse frequency. Calcitonin gene-related peptide and prostaglandin release were completely inhibited in the presence of EMD 61753, a selective kappa-opioid receptor agonist. No significant release of substance P was observed. The data demonstrate a primary release of calcitonin gene-related peptide from unmyelinated but not myelinated primary afferents in the rat skin, which is accompanied by a secondary liberation of prostaglandin E2, connecting neurogenic inflammation to general mechanisms of inflammation.
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Affiliation(s)
- M Kress
- Institute of Physiology and Experimental Pathophysiology, University of Erlangen-Nürnberg, Erlangen, Germany
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22
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Bester H, Allchorne AJ, Woolf CJ. Recovery of C-fiber-induced extravasation following peripheral nerve injury in the rat. Exp Neurol 1998; 154:628-36. [PMID: 9878197 DOI: 10.1006/exnr.1998.6953] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Peripheral nerve injury leads to substantial alterations in injured sensory neurons. These include cell death, phenotypic modifications, and regeneration. Primary sensory neurons have recently been shown not to die until a time beyond 4 months following a nerve crush or ligation and this loss is, moreover, limited to cells with unmyelinated axons, the C-fibers. The late loss of C-fibers may be due to a lack of target reinnervation during the regenerative phase. In order to investigate this, we have used a particular peripheral function, unique to C-fibers, as a measure of peripheral reinnervation: an increase in capillary permeability on antidromic activation of C-fibers, i.e., neurogenic extravasation. This was investigated in rats that had received a nerve crush injury 1 to 50 weeks earlier. Some recovery of the capacity of C-fibers to generate extravasation was detected at 8-10 weeks, which increased further at 12-14 weeks, and then plateaued at this level with no further recovery at 30 or 50 weeks. In intact and damaged sciatic nerves, A beta-fibers never induced extravasation. These findings are compatible with the hypothesis that those C-fibers which make it back to their peripheral targets do not subsequently die and those that do not, may die.
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Affiliation(s)
- H Bester
- Department of Anatomy and Developmental Biology, University College London, Medawar Building, Gower Street, London, WC1E 6BT, United Kingdom
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Sheykhzade M, Nyborg NC. Caliber dependent calcitonin gene-related peptide-induced relaxation in rat coronary arteries: effect of K+ on the tachyphylaxis. Eur J Pharmacol 1998; 351:53-9. [PMID: 9698205 DOI: 10.1016/s0014-2999(98)00290-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The influence of vessel caliber on rat calcitonin gene-related peptide (rat-alphaCGRP)-induced responses and the reproducibility of rat-alphaCGRP concentration-response curves were investigated in the left intramural coronary artery of Sprague-Dawley rats. Rat-alphaCGRP (10(-11)-10(-7) M) induced concentration-dependent relaxations with a pD2-value equal to 8.43 +/- 0.05 (n = 44) and maximal relaxation equal to 52 +/- 3% (n = 44). Both the maximal relaxation and the sensitivity to rat-alphaCGRP were significantly and inversely correlated with vessel lumen diameter. The coronary arteries developed tachyphylaxis in response to rat-alphaCGRP, which was concentration dependently decreased by activating the vessels twice with a buffer containing 36 or 125 mM K+. The rat-alphaCGRP-curve became fully reproducible after activation of the arteries twice with 125 mM K+. These results indicate a caliber-related dependency of both the effect of and sensitivity to rat-alphaCGRP in intramural rat coronary arteries because the arteries become more sensitive and reactive to rat-alphaCGRP with decreasing caliber. Tachyphylaxis can be avoided by repeated activation with 125 mM K+.
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Affiliation(s)
- M Sheykhzade
- Department of Pharmacology, The Royal Danish School of Pharmacy, Copenhagen O.
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Reslerova M, Loutzenhiser R. Renal microvascular actions of calcitonin gene-related peptide. THE AMERICAN JOURNAL OF PHYSIOLOGY 1998; 274:F1078-85. [PMID: 9841499 DOI: 10.1152/ajprenal.1998.274.6.f1078] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Calcitonin gene-related peptide (CGRP) is a potent vasodilator that is suggested to act via ATP-sensitive K channels (KATP). In the present study, we examined the actions of CGRP on pressure- and angiotensin II-induced vasoconstriction, using the in vitro perfused hydronephrotic rat kidney. Elevated pressure (from 80 to 180 mmHg) and 0.1 nM angiotensin II elicited similar decreases in afferent diameter in this model. CGRP inhibited myogenic reactivity in a concentration-dependent manner, completely preventing pressure-induced constriction at 10 nM (95 +/- 10% inhibition). These effects were partially attenuated by 10 microM glibenclamide (62 +/- 16% inhibition, P = 0.025), indicating both KATP-dependent and -independent actions of CGRP. In contrast, 10 nM CGRP inhibited angiotensin II-induced vasoconstriction by only 54 +/- 11%, and this action was not affected by glibenclamide (41 +/- 11%, P = 0.31). CGRP also inhibited the efferent arteriolar response to angiotensin II in the absence and presence of glibenclamide. Pinacidil (1.0 microM), a KATP opener also preferentially inhibited pressure- vs. angiotensin II-induced vasoconstriction (97 +/- 5 and 59 +/- 13% inhibition, respectively; P = 0.034). We conclude that the renal vasodilatory mechanisms of CGRP are pleiotropic and involve both KATP-dependent and -independent pathways. The effectiveness of CGRP in opposing renal vasoconstriction and the role of KATP in this action appear to depend on the nature the underlying vasoconstriction. We suggest that this phenomenon reflects an inhibition of KATP activation by angiotensin II.
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Affiliation(s)
- M Reslerova
- Department of Pharmacology and Therapeutics, University of Calgary, Calgary, Alberta, Canada
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25
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Sheykhzade M, Nyborg NC. Characterization of calcitonin gene-related peptide (CGRP) receptors in intramural coronary arteries from male and female Sprague Dawley rats. Br J Pharmacol 1998; 123:1464-70. [PMID: 9579744 PMCID: PMC1565309 DOI: 10.1038/sj.bjp.0701760] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
1. In this study we characterized the CGRP-receptor subtype by Schild-plot analysis using the C-terminal fragment, human-alphaCGRP(8-37), a putative competitive CGRP1-receptor selective antagonist. In addition, the effect of rat-alphaCGRP was compared with that of homologous peptides rat-betaCGRP, rat-amylin, rat-adrenomedullin and [Cys(Acm)2,7]-human-alphaCGRP, a putative selective CGRP2-receptor agonist, in the left coronary arteries of 3 months old male and female Sprague Dawley rats. 2. Isolated rings from the distal, intramural part of the left anterior descending (LAD) coronary artery in both groups of rats were mounted on a double wire-myograph. The arteries were then stretched to their optimal lumen diameter for active tension development and precontracted with 10(-5) M prostaglandin F2alpha (PGF2alpha), after which agonists were added to the organ bath in a cumulative manner. 3. Rat-alphaCGRP induced endothelium-independent relaxations in male and female Sprague-Dawley rats. Rat-betaCGRP concentration-response relations (10[-11]-10[-7] M) were similar to those of rat-alphaCGRP in either sex. The maximal relaxations induced by rat-amylin and rat-adrenomedullin, both at 10(-6) M, were significantly (P<0.05) lower than those induced by rat-alpha- and rat-betaCGRP. In contrast, the selective CGRP2-receptor agonist [Cys(Acm)2,7]-human-alphaCGRP failed to induce significant relaxations at the highest concentration used (10[-7] M) in the coronary arteries of male and female rats. 4. The C-terminal fragment, human-alphaCGRP(8-37) blocked concentration-dependently (10[-7]-10[-6] M) the rat-alphaCGRP-induced relaxation in 10(-5) M PGF2alpha-precontracted coronary arteries. The slopes of the regression lines of the Schild-plots for both male and female rats were not significantly (P>0.05) different from unity and the pA2 values for human-alphaCGRP(8-37) were 6.93 and 6.98 in arteries from male and female rats, respectively. There was no significant (P>0.05) difference in estimated pKB values for human-alphaCGRP(8-37) between male (6.99+/-0.10, n=13) and female (6.95+/-0.08, n=13) rats. 5. The concentration-response relationships for rat-alpha- and rat-betaCGRP were similar in male and female Sprague Dawley rats. The predominant CGRP receptor subtype in small intramural coronary arteries appeared to belong to the CGRP1-receptor subtype in both sexes.
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Affiliation(s)
- M Sheykhzade
- Department of Pharmacology, The Royal Danish School of Pharmacy, Copenhagen O
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Wellman GC, Quayle JM, Standen NB. ATP-sensitive K+ channel activation by calcitonin gene-related peptide and protein kinase A in pig coronary arterial smooth muscle. J Physiol 1998; 507 ( Pt 1):117-29. [PMID: 9490826 PMCID: PMC2230768 DOI: 10.1111/j.1469-7793.1998.117bu.x] [Citation(s) in RCA: 130] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/1997] [Accepted: 10/16/1997] [Indexed: 02/06/2023] Open
Abstract
1. We used patch clamp to study whole-cell K+ currents activated by calcitonin gene-related peptide (CGRP) in smooth muscle cells freshly dissociated from pig coronary arteries. 2. CGRP (50 nM) activated an inward current at -60 mV in symmetrical 140 mM K+ that was blocked by glibenclamide (10 microM), an inhibitor of ATP-sensitive potassium (KATP) channels. CGRP-induced currents were larger in cells dialysed with 0.1 mM ATP than with 3.0 mM ATP. 3. Forskolin (10 microM) activated a glibenclamide-sensitive current, as did intracellular dialysis with cAMP (100 microM). The catalytic subunit of cAMP-dependent protein kinase (protein kinase A, PKA), added to the pipette solution, activated equivalent currents in five out of twelve cells. 4. CGRP-induced currents were reduced by the PKA inhibitors adenosine 3',5'-cyclic monophosphorothioate, RP-isomer, triethylammonium salt (Rp-cAMPS; 100 microM) and N-[2-((p-bromocinnamyl)amino)ethyl]-5-isoquinolinesulphonamide+ ++ dihydrochloride (H-89; 1 microM), and abolished by inclusion of a PKA inhibitor peptide in the pipette solution. 5. The beta-adrenergic agonist isoprenaline (10 microM) also activated a glibenclamide-sensitive K+ current. 6. CGRP-induced currents were unaffected by the inhibitor of cGMP-dependent protein kinase (PKG) KT5823 (1 microM). Sodium nitroprusside (10 microM) did not activate a glibenclamide-sensitive current in cells held at -60 mV, but did activate an outward current at +60 mV that was abolished by KT5823, or by 100 nM iberiotoxin (an inhibitor of BKCa channels). 7. Our findings suggest that CGRP activates coronary KATP channels through a pathway that involves adenylyl cyclase and PKA, but not PKG.
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Affiliation(s)
- G C Wellman
- Ion Channel Group, Department of Cell Physiology and Pharmacology, University of Leicester, PO Box 138, Leicester LE1 9HN, UK
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Lundgaard A, Aalkjaer C, Bjurholm A, Mulvany MJ, Hansen ES. Vasorelaxation in isolated bone arteries. Vasoactive intestinal peptide, substance P, calcitonin gene-related peptide, and bradykinin studied in pigs. ACTA ORTHOPAEDICA SCANDINAVICA 1997; 68:481-9. [PMID: 9385251 DOI: 10.3109/17453679708996267] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We assessed the effects of vasoactive intestinal peptide (VIP), calcitonin gene-related peptide (CGRP), substance P (SP), and bradykinin in arteries (diameter approximately 230 microns) isolated from cancellous bone from pigs. Arterial segments (2 mm long) were mounted on a myograph for measurement of isometric force development. After submaximal precontraction with norepinephrine, VIP (10(-10)-10(-7) M), CGRP (10(-11)-10(-7) M), SP (10(-6) M), and bradykinin (10(-11)-10(-6) M) were added. 44 arterial segments (23 pigs) were investigated. VIP-, CGRP-, and bradykinin induced a concentration-dependent vasorelaxation, while SP mediated a transient relaxation. After mechanical removal of the endothelium, the effects of SP and bradykinin were completely abolished, while the relaxation to CGRP was still pronounced. This indicates that the effects of SP and bradykinin are mediated by the endothelium, while CGRP mainly mediates relaxation by a direct effect on vascular smooth muscle cells. The relaxations to CGRP and bradykinin were still significant after inhibition of nitric oxide synthase with 10(-4) M N omega-nitro-L-arginine (L-NNA) and inhibition of prostaglandin synthesis with 10(-5) M indomethacin, indicating the existence of an alternative vasorelaxing pathway. Our findings support the theory of a vasoregulatory role of neuropeptides in bone.
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Affiliation(s)
- A Lundgaard
- Institute of Pharmacology, Stockholm, Sweden, Denmark
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Pomerleau F, Fournier A, Cadieux A. Mouse aorta: a preparation highly sensitive to the vasodilatory action of CGRP. J Cardiovasc Pharmacol 1997; 30:343-51. [PMID: 9300319 DOI: 10.1097/00005344-199709000-00012] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Calcitonin gene-related peptide (CGRP), carbamylcholine, and vasoactive intestinal peptide (VIP) caused a concentration-related relaxation in mouse aorta precontracted to noradrenaline. Maximal relaxations obtained were 110, 44, and 46% with median effective concentrations (EC50) values of 7.8, 813.7, and 24.5 nM for CGRP, carbamylcholine, and VIP, respectively. The carbamylcholine- and VIP-induced relaxations were exclusively mediated by endothelial cell-derived factors, whereas CGRP maintained a full vasodilatory action in denuded aorta. However, its concentration-response curve was slightly shifted to the right in the absence of endothelium. The relaxation caused by CGRP was also slightly inhibited at 2 x 10(-8) M by removal of endothelium and in the presence of methylene blue, NG-nitro-L-arginine methylester (L-NAME), or glibenclamide but was not affected by atropine, propranolol, indomethacin, or tetrodotoxin. Moreover, the absence of Ca2+ in the bathing solution had no inhibitory effect on CGRP-induced relaxation in noradrenaline-precontracted aorta. It is concluded that the relaxation evoked by CGRP in the mouse aorta does not mainly depend on an endothelium-derived factor or on the activation of ATP-sensitive K+ (KATP) channels but rather is caused by a mechanism primarily associated with the inhibition of the mobilization of intracellular Ca2+.
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Affiliation(s)
- F Pomerleau
- Department of Pharmacology, Faculty of Medicine, University of Sherbrooke, Quebec, Canada
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Bell D, Tamamori M, Marumo F, Hiroe M, McDermott BJ, Ito H. Calcitonin gene-related peptide (CGRP) increases cell surface area and induces expression of skeletal alpha-actin ANP mRNA in hypertrophying neonatal cardiomyocytes. REGULATORY PEPTIDES 1997; 71:1-7. [PMID: 9299635 DOI: 10.1016/s0167-0115(97)01015-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We have reported previously that calcitonin gene-related peptide (CGRP) exerts hypertrophic effects, defined in the broadest sense as increased mass of protein per cell, in adult rat ventricular in vitro. The aim of the present investigation was to determine whether the peptide also increases the cell surface area of, and induces expression of ANP and skeletal alpha-actin mRNA in hypertrophying neonatal rat ventricular cardiomyocytes. Cells cultured in the presence of CGRP were invisibly hypertrophied after 48 h compared to cells cultured in serum-free MEM for the same period. CGRP, 100 pM and 1 nM, increased cell surface area significantly and to values 1.82- and 2.15-fold greater, respectively, than in the absence of peptide (659.64 +/-23.48 microns 2, n = 10). The selective antagonist at CGRP1, receptors, CGRP8-37(200nM), significantly attenuated the effects of CGRP (100 pM and 1 nM). CGRP caused a marked up-regulation of the expression of mRNA encoding skeletal alpha-actin and ANP, respectively, maximally after 12 h and at a concentration of 100 pM, to values approximately 3.6- and 2.5-fold greater than in the absence of peptide. These effects of the peptide were completely abolished in the presence of CGRP8-37(100 nM). In conclusion, CGRP increases cell surface area and induces expression of ANP and skeletal alpha-actin mRNA in hypertrophying cardiomyocytes via the CGRP1, receptor subtype.
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Affiliation(s)
- D Bell
- Second Department of Internal Medicine, Tokyo Medical and Dental University, Japan
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Saetrum Opgaard O, Edvinsson L. Effect of parasympathetic and sensory transmitters on human epicardial coronary arteries and veins. PHARMACOLOGY & TOXICOLOGY 1996; 78:273-9. [PMID: 8861787 DOI: 10.1111/j.1600-0773.1996.tb00217.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Vasomotor effects of various agonists were tested on isolated human epicardial coronary arteries and veins at resting tension and after precontraction with U46619. Acetylcholine relaxed all arteries with intact endothelium but only some endothelium-denuded arteries. Most veins did not relax to acetylcholine. Higher concentrations of acetylcholine induced powerful contractions of all arteries and veins. Preincubation with atropine significantly lowered the pD(2) values but not E(max) values for contractile responses to acetylcholine in arteries and veins (pA(2) value for atropine 9.1 arteries and 9.6 veins). Vasoactive intestinal peptide, human alpha-calcitonin gene-related peptide and substance P potently relaxed all arteries with intact endothelium and all veins. Removal of the arterial endothelium abolished relaxation to substance P in most arteries whereas responses to vasoactive intestinal peptide were unaffected, and for alpha-calcitonin gene-related peptide the pD(2) value but not the E(max) value was significantly lowered. In both arteries and veins, the antagonists alpha-calcitonin gene-related peptide (8-37) and spantide lowered significantly the potency for alpha-calcitonin gene-related peptide and substance P, respectively, without significant changes in E(max) values (pA(2) value for alpha-calcitonin gene-related peptide (8-37) 7.9 arteries and 7.9 veins, for spantide 7.6 arteries and 8.1 veins).
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Affiliation(s)
- O Saetrum Opgaard
- Department of Internal Medicine, University Hospital of Lund, Sweden
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Kajimoto N, Ogawa H, Suzuki A. Changes of endothelial functions in the coronary artery after chronic nitroarginine feeding. CLINICAL AND EXPERIMENTAL PHARMACOLOGY & PHYSIOLOGY. SUPPLEMENT 1995; 22:S154-6. [PMID: 9072335 DOI: 10.1111/j.1440-1681.1995.tb02861.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
1. The effects of chronic NG-nitro-L-arginine (LNA) feeding on the endothelial function in isolated coronary arteries from stroke-prone spontaneously hypertensive rats (SHRSP) and normotensive Wistar-Kyoto (WKY) rats were studied. 2. A diet containing LNA (0.02%) was given to male SHRSP and WKY at 6 weeks of age and the coronary arteries were dissected on the 10th day of feeding. 3. In the SHRSP and WKY fed the LNA-free diet, acetylcholine (ACh) relaxed the precontracted ring segments of the coronary artery with intact endothelium in a dose-dependent manner. The reactivity was stronger in the WKY than in the SHRSP. However, the ACh-induced relaxation after the LNA-feeding was significantly stronger in the coronary arteries from the WKY than in those from the SHRSP. 4. The relaxation induced by the calcitonin gene-related peptide (CGRP) was endothelium-dependent and endothelium-independent. The degree of the response in the rats fed the LNA-containing diet was not significantly different from that in the rats fed the LNA-free diet. 5. The vasodilator response induced by sodium nitroprusside (SNP) was dose-dependent and similar in the rats fed the LNA containing diet and the LNA-free diet. 6. These findings indicate that chronic LNA feeding markedly impaired the endothelial nitric oxide formation in the coronary artery from young SHRSP.
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Affiliation(s)
- N Kajimoto
- Department of Pharmacology, Kinki University School of Medicine, Osakasayama, Japan
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Miura K, Ebara T, Okumura M, Matsuura T, Kim S, Yukimura T, Iwao H. Attenuation of adrenomedullin-induced renal vasodilatation by NG-nitro L-arginine but not glibenclamide. Br J Pharmacol 1995; 115:917-24. [PMID: 7582521 PMCID: PMC1909021 DOI: 10.1111/j.1476-5381.1995.tb15898.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
1. The present study was conducted in order to elucidate the in vivo contribution of nitric oxide (NO) and the glibenclamide-sensitive potassium channel in the renal action of adrenomedullin in anaesthetized dogs. 2. Intrarenal arterial infusion of adrenomedullin (20 ng kg-1 min-1) elicited a pronounced increase in renal blood flow with no changes in systemic blood pressure. The renal vasodilator action of adrenomedullin was markedly attenuated by pretreatment with NG-nitro L-arginine (L-NOARG), but this was reversed by continuous infusion of L-arginine. 3. Pretreatment with glibenclamide almost completely blocked the renal vasodilatation induced by lemakalim, but had no effect on the renal vasodilator and diuretic action of adrenomedullin. 4. Intrarenal arterial infusion of adrenomedullin induced diuresis and natriuresis. Diuretic and natriuretic action of adrenomedullin was also attenuated by L-NOARG. L-Arginine partly reversed the effect of L-NOARG and adrenomedullin-induced diuresis and natriuresis. 5. These data indicate that the in vivo renal vasodilator action of adrenomedullin is mediated by the release of NO. The glibenclamide-sensitive potassium channel is not involved in the renal action of adrenomedullin, at least, not in anaesthetized dogs. Since the inhibition of L-NOARG of adrenomedullin-induced diuresis occurred concomitantly with the attenuation of the renal vasodilator action of adrenomedullin, direct involvement of NO in adrenomedullin-induced diuresis remains to be established.
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Affiliation(s)
- K Miura
- Department of Pharmacology, Osaka City University Medical School, Japan
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Nyborg NC, Nielsen PJ. Beta-adrenergic receptors regulating vascular smooth muscle tone are only localized to the intraocular segment of the long posterior ciliary artery in bovine eye. Surv Ophthalmol 1995; 39 Suppl 1:S66-75. [PMID: 7660314 DOI: 10.1016/s0039-6257(05)80075-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Beta-adrenergic drugs are important drugs in glaucoma treatment. Their exact mechanism of action is not yet fully understood but a decreased perfusion pressure in the ciliary body due to blockade of vasodilatory beta-adrenoceptors is thought to participate in the reduction of intraocular pressure. This study investigates the vasodilator action of beta adrenergic-agents in intra- and extraocular arteries from bovine and human eyes. Ring segments of retinal, choroidal, intraocular segment of long posterior ciliary artery, and segments of extraocular posterior ciliary arteries from bovine eyes and short posterior ciliary arteries from freshly enucleated human eyes were mounted on an isometric myograph and their reactivity to beta-adrenergic drugs were studied. Of all vessel types examined only the intraocular segment of long posterior ciliary artery precontracted with prostaglandin F2 alpha responded to 1-isoprenaline (1 nM-1 microM) with a graded concentration-dependent relaxation (32 +/- 7%, n = 10) and a pD2 of 7.5 +/- 0.2 concentrations of 1-isoprenaline greater than 1 microM induced contractions which were antagonized by a combined blockade of alpha1- and alpha2-adrenoceptors. Salbutamol (selective beta2-agonist) induced relaxations of similar magnitude as that of 1-isoprenaline but the sensitivity of the intraocular segment of long posterior ciliary arteries to salbutamol was 312 times less than that to 1-isoprenaline, pD2 7.2 +/- 0.2 and 4.4 +/- 0.1 (n = 6), respectively, whereas dobutamine (selective beta 1-agonist) had no effect between 1 nM and 10 microM. Betaxolol (selective beta 1-antagonist) and 1CI 115811 (selective beta 2-antagonist) competitively antagonized isoprenaline-induced relaxations giving pKB-values of 5.9 +/- 0.1 (n = 11) and 8.5 +/- 0.1 (n = 6), respectively. The slope of the Schild-plots were equal to unity. Human posterior ciliary arteries with spontaneous tone or tone induced by 10 microM PGF2 alpha did not react to isoprenaline (1 nM-10 microM). The bovine intraocular segment of long posterior ciliary arteries contracted to 1-noradrenaline without alpha-adrenoceptor blockade and addition of propranolol or cocaine did not change the concentration-response curve. 1-Phenylephrine and B-HT933 induced both potent and strong contractions indicating the presence of both alpha 1- and alpha 2-adrenoceptors in these arteries. Although beta-adrenoceptors have been identified in various parts of the ocular circulation by radio-ligand binding techniques our data show that beta-adrenoceptors linked to regulation of vascular tone are only found in intraocular branches of the intraocular segment of long posterior ciliary artery in bovine eyes.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- N C Nyborg
- Department of Pharmacology, Aarhus University, Denmark
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Kobayashi D, Todoki K, Ozono S, Okabe E. Calcitonin gene-related peptide mediated neurogenic vasorelaxation in the isolated canine lingual artery. JAPANESE JOURNAL OF PHARMACOLOGY 1995; 67:329-39. [PMID: 7544421 DOI: 10.1254/jjp.67.329] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The nature of neurogenic relaxation was investigated in ring preparations of canine lingual artery. In all experiments, the preparations were previously treated with guanethidine (5 x 10(-6) M) to block neurogenic constrictor responses. In the presence of norepinephrine (10(-5) M) to induce tone, electrical stimulation (10 V, 4 to 16 Hz, for 45 sec) produced relaxation of the rings in an endothelium-independent fashion. The relaxant response in endothelium-denuded rings was not changed by propranolol (10(-5) M), and atropine (10(-5) M) did not affect the relaxation elicited by electrical stimulation in endothelium-intact rings. NG-monomethyl-L-arginine (10(-4) M) or NG-nitro-L-arginine methyl ester (10(-4) M), a nitric oxide (NO) synthase inhibitor, had no effect on the electrical stimulation-induced relaxation of endothelium-denuded rings. Human calcitonin gene-related peptide (CGRP)-(8 - 37) (2 x 10(-8) M), a CGRP1-receptor antagonist, inhibited neurogenic relaxation of endothelium-denuded rings; substance P (10(-6) M) failed to mimic the observed effect of electrical stimulation. The demonstrated effect of electrical stimulation was inhibited by glibenclamide (10(-5) M), but not tetraethylammonium (2 x 10(-4) M); glibenclamide abolished the relaxation in response to exogenous CGRP or the ATP-sensitive K+ channel opener cromakalim (10(-6) M) in endothelium-denuded rings. Moreover, tetrodotoxin (3.13 x 10(-6) M) inhibited the relaxation of endothelium-denuded rings induced by electrical stimulation. The relaxation was selectively inhibited when endogenous CGRP had been depleted from perivascular nerves by capsaicin (10(-6) M). These results suggest that CGRP, but not NO, released from non-adrenergic non-cholinergic nerves by electrical stimulation produces relaxation of canine lingual artery that is mediated by activation of CGRP1 receptors.
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Affiliation(s)
- D Kobayashi
- Department of Pharmacology, Kanagawa Dental College, Japan
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Lo YC, Wu SN, Wu JR, Chen IJ. Effect of capsaicin on membrane currents in cultured vascular smooth muscle cells of rat aorta. Eur J Pharmacol 1995; 292:321-8. [PMID: 7540981 DOI: 10.1016/0926-6917(95)90039-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The application of capsaicin (1 microM) produced a minor relaxant effect in endothelium-denuded rat aortae. However, capsaicin caused a greater relaxation of blood vessels precontracted with high K+ or phenylephrine. The effects of capsaicin on the ionic currents were also examined in A7r5 vascular smooth muscle cells. The tight-seal whole-cell voltage clamp technique was used. Capsaicin inhibited the Ba2+ inward current (IBa) through the voltage-dependent L-type Ca2+ channel in a concentration-dependent fashion, whereas calcitonin gene-related peptide and phenylephrine produced a minor increase in IBa. Capsaicin did not alter the overall shape of current-voltage relationship of IBa. However, capsaicin (3 microM) shifted the quasi-steady-state inactivation curve of IBa to more negative membrane potential by about 5 mV. These effects of capsaicin on IBa were reversible. In addition, capsaicin had inhibitory effects on voltage dependent K+ currents. These results suggest that inhibition of the voltage-dependent L-type Ca2+ channel is involved in the capsaicin-induced relaxation of the vascular smooth muscle, whereas capsaicin-induced inhibition of voltage-dependent K+ channels might produce an increase in cell excitability.
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MESH Headings
- Animals
- Aorta, Thoracic/cytology
- Aorta, Thoracic/drug effects
- Aorta, Thoracic/metabolism
- Capsaicin/pharmacology
- Cell Membrane/drug effects
- Cell Membrane/metabolism
- Cells, Cultured
- Electrophysiology
- Endothelium, Vascular/physiology
- Ion Channels/drug effects
- Ion Channels/metabolism
- Muscle Contraction/drug effects
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Patch-Clamp Techniques
- Rats
- Rats, Wistar
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Affiliation(s)
- Y C Lo
- Department of Pharmacology, Kaohsiung Medical College, Taiwan
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Maggi CA. Tachykinins and calcitonin gene-related peptide (CGRP) as co-transmitters released from peripheral endings of sensory nerves. Prog Neurobiol 1995; 45:1-98. [PMID: 7716258 DOI: 10.1016/0301-0082(94)e0017-b] [Citation(s) in RCA: 345] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- C A Maggi
- Department of Pharmacology, A. Menarini Pharmaceuticals, Florence, Italy
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37
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Hoffman JI, Piedimonte G, Maxwell AJ, Nadel JA, Iwanaga S, Husseini WK. Aspects of coronary vasomotor regulation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1995; 381:135-46. [PMID: 8867830 DOI: 10.1007/978-1-4615-1895-2_13] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- J I Hoffman
- Department of Pediatrics and Internal Medicine, University of California, San Francisco 94143, USA
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Abstract
The plexus-free longitudinal muscle was used to investigate the muscle-relaxing effects of the known K+ channel openers, cromakalim, pinacidil and nicorandil, and compared with other known muscle relaxants, calcitonin gene-related peptide (CGRP) and isoprenaline. The three K+ channel openers all decreased basal tension and inhibited the tonic tension evoked by 30 mM KCl, 0.5 microM histamine or 0.1 microM oxotremorine in a dose-dependent manner. The order of potency is cromakalim > pinacidil > nicorandil in KCl or oxotremorine-precontracted muscle strip and nicorandil > cromakalim > pinacidil in histamine-precontracted muscle strip. Inhibition by cromakalim was completely reversed by glibenclamide, a blocker of ATP-sensitive K+ channels, while inhibition by nicorandil or pinacidil was only partially antagonized. The tonic tension evoked by KCl, histamine or oxotremorine was relaxed by CGRP or isoprenaline. Inhibition by neither of these compounds was relieved by glibenclamide. These results suggest that while ATP-sensitive K+ channels may be present in the longitudinal muscle cells, they may not be involved in the actions of CGRP or isoprenaline on the longitudinal muscle.
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Affiliation(s)
- Y D Sun
- Department of Physiology, University of Alberta Faculty of Medicine, Edmonton, Canada
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Richard V, Kaeffer N, Hogie M, Tron C, Blanc T, Thuillez C. Role of endogenous endothelin in myocardial and coronary endothelial injury after ischaemia and reperfusion in rats: studies with bosentan, a mixed ETA-ETB antagonist. Br J Pharmacol 1994; 113:869-76. [PMID: 7858879 PMCID: PMC1510467 DOI: 10.1111/j.1476-5381.1994.tb17073.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
1. Previous studies suggested that endothelin-1 (ET-1) may play a role in myocardial ischaemia and reperfusion. This study was designed to test the effect of a new nonpeptide antagonist of endothelin ETA and ETB receptors, bosentan, on myocardial infarct size, ventricular arrhythmias, and coronary endothelial dysfunction after ischaemia and reperfusion. 2. Anaesthetized male Wistar rats were subjected to 20 min ischaemia (left coronary artery occlusion) followed by 1 h (for the evaluation of coronary endothelial dysfunction) or 2 h (for the evaluation of infarct size) reperfusion, or 5 min ischaemia followed by 15 min reperfusion (for the evaluation of reperfusion arrhythmias). Vascular studies were performed on 1.5-2 mm coronary segments (internal diameter 250-300 microns) removed distal to the site of occlusion and mounted in wire myographs for isometric tension recording. Area at risk and infarct size were determined by Indian ink injection and triphenyl tetrazolium staining, using computerized analysis of enlarged sections after colour video acquisition. 3. Bosentan, administered at a dose which virtually abolished the pressor response to big ET-1 (3 mg kg-1, i.v. before ischaemia) did not affect heart rate, arterial pressure or the rate pressure product before ischaemia, during ischaemia and during reperfusion. Bosentan did not affect the incidence of reperfusion-induced ventricular fibrillation (controls: 86%, n = 14; bosentan: 93%, n = 15), and did not modify infarct size (% of area at risk: controls: 63 +/- 4, n = 10; bosentan: 60 +/- 6, n = 8). Ischaemia followed by reperfusion markedly reduced the endothelium-dependent relaxations to acetylcholine(maximal response: sham: 59 +/- 4%, n = 9; ischaemia-reperfusion: 26+/- 6%, n = 8; P<0.01), characteristic of reperfusion-induced endothelial dysfunction, and this dysfunction was not prevented by bosentan (maximal response to acetylcholine: 25 +/-5%, n = 9; P<0.01 vs sham; P = NS vs ischaemia/reperfusion).4. These experiments suggest that endogenous endothelin does not contribute to myocyte or coronary endothelial injury in this rat model of ischaemia and reperfusion.
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Affiliation(s)
- V Richard
- Department of Pharmacology, VACOMED, IFRMP, Rouen University Medical School, France
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Yaoita H, Sato E, Kawaguchi M, Saito T, Maehara K, Maruyama Y. Nonadrenergic noncholinergic nerves regulate basal coronary flow via release of capsaicin-sensitive neuropeptides in the rat heart. Circ Res 1994; 75:780-8. [PMID: 7522988 DOI: 10.1161/01.res.75.4.780] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Nonadrenergic noncholinergic nerve fibers supposedly modulate basal coronary flow by releasing capsaicin-sensitive neuropeptides, but the physiological effects of this intrinsic action have not been clarified. We investigated the intrinsic function of nonadrenergic noncholinergic innervation in modulating basal coronary flow in rats. We administered capsaicin to 44 rats to deplete neuropeptides such as calcitonin gene-related peptide (CGRP) and substance P and administered inert vehicle to 60 control rats. Four days later, we measured the coronary pressure-flow relation in the basal state and during maximal coronary vasodilation induced by intracoronary adenosine administration using Langendorff's method. Changes in basal coronary flow prompted by intracoronary infusion of CGRP or substance P and their antagonists were measured in 54 and 30 rats, respectively. Capsaicin-treated rats showed a 31.5 +/- 0.9% (mean +/- SEM) reduction (P < .01) of basal coronary flow in the range of perfusion pressures between 60 and 140 mm Hg compared with untreated control rats, but the maximal coronary flow after adenosine was similar between the two groups. Although basal coronary flow was reduced in capsaicin-treated hearts, left ventricular contractile force and myocardial oxygen consumption did not fall significantly. CGRP increased the coronary flow, but substance P did not. CGRP(8-37), a CGRP receptor antagonist, reduced basal coronary flow by 24.5 +/- 2.1% (P < .01), but FK888, a substance P antagonist, had little effect on it. Thus, capsaicin-sensitive neuropeptides in the rat heart modulate basal coronary flow, providing approximately 30% of it.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- H Yaoita
- First Department of Internal Medicine, Fukushima Medical College, Japan
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41
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Richard V, Kaeffer N, Tron C, Thuillez C. Ischemic preconditioning protects against coronary endothelial dysfunction induced by ischemia and reperfusion. Circulation 1994; 89:1254-61. [PMID: 8124814 DOI: 10.1161/01.cir.89.3.1254] [Citation(s) in RCA: 123] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BACKGROUND Repetitive, brief periods of ischemia and reperfusion ("preconditioning") increase the resistance of myocardial tissue to subsequent prolonged ischemic episodes and limit infarct size. We investigated whether preconditioning also protects against coronary endothelial dysfunction induced by ischemia and reperfusion. METHODS AND RESULTS Experiments were performed in four groups of rats (n = 8 in each group): group 1 rats underwent sham surgery, group 2 rats were subjected to 20 minutes of left coronary artery occlusion without reperfusion, group 3 rats underwent 20 minutes of occlusion followed by 1 hour of reperfusion, and group 4 rats (preconditioning group) underwent the same protocol as group 3 rats, preceded by three cycles of 5 minutes of ischemia and 5 minutes of reperfusion. At the end of the experiments, coronary segments (internal diameter, 250 to 300 microns) were removed distal to the occlusion site and mounted in wire myographs for isometric tension recording. Relaxations induced by increasing concentrations of acetylcholine, the calcium ionophore A23187, or the nitric oxide (NO) donor SIN-1 were determined in arteries precontracted by serotonin. Basal NO release was estimated by measuring contractions to NG-nitro L-arginine methyl ester (L-NAME). In addition, we determined the effect of preconditioning on infarct size in two additional groups that were subjected to the same protocols as those of groups 3 and 4. In those animals, area at risk (India ink injection) and infarct size (triphenyltetrazolium stain) were determined by computerized analysis of enlarged sections after video acquisition. Preconditioning markedly limited infarct size (percent of area at risk: controls, 57 +/- 2; preconditioning, 2.2 +/- 0.6; P < .01). Ischemia (without or with reperfusion) or preconditioning did not affect the coronary responses to L-NAME, serotonin, A23187, or SIN-1. Ischemia without reperfusion did not modify the relaxations to acetylcholine (maximal relaxation: sham, 58 +/- 4%; ischemia, 56 +/- 7%; P = NS). In contrast, ischemia followed by reperfusion markedly impaired the response to acetylcholine (26 +/- 6%; P < .01 versus sham). This impaired response was restored by preconditioning (maximal relaxation: 59 +/- 9%; P = NS versus sham; P < .01 versus ischemia/reperfusion). CONCLUSIONS In addition to protecting myocardial cells, preconditioning also protects coronary endothelial cells against ischemia/reperfusion injury.
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Affiliation(s)
- V Richard
- Department of Pharmacology, Rouen University School of Medicine, France
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Lei S, Mulvany MJ, Nyborg NC. Characterization of the CGRP receptor and mechanisms of action in rat mesenteric small arteries. PHARMACOLOGY & TOXICOLOGY 1994; 74:130-5. [PMID: 8190701 DOI: 10.1111/j.1600-0773.1994.tb01087.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Rat alpha-calcitonin gene-related peptide-induced concentration-dependent (100 pM-10 nM) relaxations in rat mesenteric small arteries (i.d. approximately 220 microns) contracted with noradrenaline, prostaglandin F2 alpha or K+, however, the maximal relaxation depended on the precontractile stimulus, being highest (95%) in arteries contracted with PGF2 alpha and lowest (51%) in arteries contracted with 125 mM K+. The relaxation was inhibited between 10 pM and 1 nM by removal of the endothelium, but was not antagonized by glibenclamide (1 microM), tetraethylammonium (30 mM), apamine (0.3 microM) and 4-aminopyridine (3 mM). The concentration-response curve to rat alpha-CGRP and human beta-CGRP was shifted to the right in the presence of 1 microM human alpha-CGRP(8-37) indicating a receptor affinity, -log(KB[M]), equal to 7.2 and 7.0, respectively. It is concluded that the relaxation induced by CGRP depends minimally on the endothelium and K(+)-channel opening is not a principal process in the relaxing effect of CGRP, thus a third mechanism must mediate the relaxation in these vessels. The main CGRP receptor type mediating relaxation in rat mesenteric small arteries belongs to the CGRP1 subtype.
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Affiliation(s)
- S Lei
- Department of Pharmacology, Aarhus University, Denmark
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Hao H, Fiscus RR, Wang X, Diana JN. N omega-nitro-L-arginine inhibits vasodilations and elevations of both cyclic AMP and cyclic GMP levels in rat aorta induced by calcitonin gene-related peptide (CGRP). Neuropeptides 1994; 26:123-31. [PMID: 7513384 DOI: 10.1016/0143-4179(94)90103-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Our previous studies showed that vasodilations and elevations of both cyclic AMP and cyclic GMP levels in rat aorta induced by rat calcitonin gene-related peptide (rCGRP) are inhibited by hemoglobin and methylene blue, blockers of the endothelium-derived relaxant factor (EDRF, now recognized as nitric oxide [NO]). In the present study, we used N omega-nitro-L-arginine (L-NNA), a selective inhibitor of nitric oxide synthase, to test whether rCGRP-induced relaxations and cyclic AMP and cyclic GMP responses in rat aorta require de novo synthesis of NO. L-NNA (30 microM, 15 min) inhibited by 84, 76 and 73% the relaxations induced by rCGRP at 1, 10 and 100 nM, respectively. D-NNA (30 microM), which does not inhibit nitric oxide synthase, did not block rCGRP-induced vasorelaxations. Addition of L-arginine (3 mM) 5 min before L-NNA completely prevented the L-NNA-inhibition of CGRP-induced relaxations. L-NNA (30 microM, 15 min) also inhibited the elevations of both cyclic AMP and cyclic GMP levels caused by CGRP (100 nM). The data suggest that de novo synthesis of nitric oxide from its precursor L-arginine is required for rCGRP to induce vasodilations and elevations of both cyclic AMP and cyclic GMP levels in rat aorta.
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Affiliation(s)
- H Hao
- Department of Physiology and Biophysics, Stroke Program Center of Excellence of Sanders-Brown Research Center on Aging, University of Kentucky College of Medicine, Lexington 40536-0230
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Gulbenkian S, Saetrum Opgaard O, Ekman R, Costa Andrade N, Wharton J, Polak JM, Queiroz e Melo J, Edvinsson L. Peptidergic innervation of human epicardial coronary arteries. Circ Res 1993; 73:579-88. [PMID: 7688669 DOI: 10.1161/01.res.73.3.579] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The peptidergic innervation of proximal (internal diameter, > 0.8 mm) and distal (internal diameter, < 0.8 mm) regions of human epicardial coronary arteries was investigated by means of immunohistochemical, chromatographic, radioimmunological, and in vitro pharmacological techniques. The use of an antiserum to the general neuronal marker protein gene product 9.5 revealed that the proximal part of epicardial arteries possessed a relatively sparse supply of nerve fibers forming a loose network in the adventitia. The perivascular network increased in density as the vessels were followed distally. In both proximal and distal regions, the majority of nerve fibers possessed neuropeptide Y and tyrosine hydroxylase immunoreactivity. Calcitonin gene-related peptide (CGRP)- and substance P-immunoreactive nerve fibers were very sparse in the proximal region of the arteries and increased in number distally. Only a few scattered vasoactive intestinal peptide (VIP)-immunoreactive nerve fibers were detected in both arterial regions. The use of high-performance liquid chromatography and radioimmunoassay revealed that the immunoreactive material present in coronary artery extracts closely resembled synthetic peptides. An in vitro pharmacological method demonstrated that neuropeptide Y elicited no detectable response in either proximal or distal arterial segments. In contrast, CGRP, substance P, and VIP all produced a concentration-dependent relaxation of both arterial regions. CGRP and substance P were stronger and more potent than VIP. CGRP and substance P induced a more potent response in distal compared with proximal regions of the arteries. These results suggest that the peptidergic nerves supplying human large epicardial coronary arteries may be predominantly involved in mediating vasodilation.
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Affiliation(s)
- S Gulbenkian
- Department of Cell Biology, Gulbenkian Institute of Science, Oeiras, Portugal
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Affiliation(s)
- A Shulkes
- Department of Surgery, University of Melbourne, Austin Hospital, Victoria, Australia
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46
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Abstract
In spite of the relatively large amount of in vitro and in vivo data indicating that, in a number of ways, cerebral arteries are pharmacologically different from peripheral arteries, the mechanisms responsible for these differences are far from clear. An understanding of these mechanisms is particularly important for a rational approach to the treatment of disorders of the cerebral circulation including migraine, hypertension and the responses of cerebral vessels to subarachnoid haemorrhage. This review outlines electrophysiological data which are available from cerebrovascular smooth muscle cells, including the possibility that inwardly-rectifying potassium channels, active at potentials close to the resting membrane potential, are intimately involved in the changes in smooth muscle tone which couple blood flow to regional changes in nerve cell activity. The membrane potential changes in response to perivascular nerve stimulation, noradrenaline, 5-hydroxytryptamine and endothelium-derived hyperpolarizing factor are also described, together with the underlying membrane mechanisms and their relationship to smooth muscle contraction and relaxation.
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Affiliation(s)
- F Plane
- Department of Physiology and Pharmacology, University of Southampton, U.K
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47
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Knock GA, Wharton J, Gaer JA, Yacoub MH, Taylor KM, Polak JM. Regional distribution and regulation of [125I]calcitonin gene-related peptide binding sites in coronary arteries. Eur J Pharmacol 1992; 219:415-25. [PMID: 1330610 DOI: 10.1016/0014-2999(92)90483-k] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Quantitative in vitro autoradiographic techniques were used to localize and characterize 125I-labelled human calcitonin gene-related peptide ([125I]hCGRP) binding sites in sections of bovine left anterior descending coronary artery (LAD). Specific high affinity (Kd 0.4 nM) [125I]hCGRP binding sites were localized to the media of both epicardial and myocardial coronary arteries. Binding site density was greater in distal epicardial and myocardial arteries than in proximal epicardial regions of the LAD. Binding sites exhibited a significantly higher affinity for alpha-hCGRP (Ki 1.1 nM) than for hCGRP-(8-37) (Ki 7.0 nM) and [Cys(ACM)2,7]hCGRP (Ki 27.4 nM). Guanosine-5'-O-(3-thiotriphosphate) inhibited [125I]hCGRP binding in a concentration-dependent manner. Extrinsic denervation of the bovine heart resulted in a depletion of CGRP-like immunoreactive perivascular nerve fibres and an increase in the density of coronary artery [125I]hCGRP binding sites (P = 0.0092). The regional distribution of binding sites in human coronary arteries differed from that observed in bovine and porcine vessels. It is concluded that selective, G protein-coupled, CGRP receptors are present in the media of bovine coronary arteries; there are both regional and species differences in the distribution of CGRP binding sites in coronary arteries and endogenous CGRP may exert a tonic influence on coronary vasomotor tone.
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Affiliation(s)
- G A Knock
- Department of Histochemistry, Royal Postgraduate Medical School, Hammersmith Hospital, London, UK
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Abdelrahman A, Wang YX, Chang SD, Pang CC. Mechanism of the vasodilator action of calcitonin gene-related peptide in conscious rats. Br J Pharmacol 1992; 106:45-8. [PMID: 1504730 PMCID: PMC1907442 DOI: 10.1111/j.1476-5381.1992.tb14290.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
1. The aim of this study was to investigate whether the hypotensive effect of rat alpha-calcitonin gene-related peptide (alpha CGRP) in conscious rats is mediated by endothelium-derived nitric oxide (NO) or the opening of adenosine 5'-triphosphate (ATP)-sensitive potassium (KATP) channels. 2. Dose-mean arterial pressure (MAP)-response curves of alpha CGRP were examined in the presence of vehicle, phenylephrine, KATP channel antagonist glibenclamide or NO synthase inhibitors, NG-nitro-L-arginine methyl ester (L-NAME) and NG-nitro-D-arginine methyl ester (D-NAME). Dose-MAP-response curves for sodium nitroprusside were also constructed in the presence and absence of L-NAME and D-NAME. 3. alpha CGRP and nitroprusside produced dose-dependent reductions in MAP which were potentiated by phenylephrine. Both L-NAME and D-NAME attenuated the depressor response to alpha CGRP but not nitroprusside. 4. Dose-MAP-response curves for pinacidil, a KATP-channel activator, were also examined in the presence of glibenclamide or vehicle. Glibenclamide attenuated pinacidil- but not alpha CGRP-induced reductions in MAP. 5. It is concluded that the hypotensive effects of alpha CGRP are partially mediated via endothelium-derived NO but not via the opening of KATP channels.
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Affiliation(s)
- A Abdelrahman
- Department of Pharmacology & Therapeutics, Faculty of Medicine, University of British Columbia, Vancouver, Canada
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Abstract
Calcitonin gene-related peptide (CGRP) shows diversity both in its effects and its receptors. It is likely to have roles as a neurotransmitter, neuromodulator, local hormone and trophic factor. Its effects include rapid changes in neuronal activity, relaxation of many types of smooth muscle, actions on metabolism and changes in gene expression. Receptor heterogeneity has been revealed from experiments comparing agonist potency ratios and antagonist affinities. The evidence from these approaches is reviewed in this article and a speculative receptor classification scheme is proposed. Some of the likely future directions for CGRP research are discussed.
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Affiliation(s)
- D R Poyner
- Department of Pharmaceutical Sciences, Aston University, Aston Triangle, Birmingham, U.K
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