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Giuriato G, Venturelli M, Matias A, Soares EMKVK, Gaetgens J, Frederick KA, Ives SJ. Capsaicin and Its Effect on Exercise Performance, Fatigue and Inflammation after Exercise. Nutrients 2022; 14:232. [PMID: 35057413 PMCID: PMC8778706 DOI: 10.3390/nu14020232] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2021] [Revised: 12/30/2021] [Accepted: 01/02/2022] [Indexed: 01/27/2023] Open
Abstract
Capsaicin (CAP) activates the transient receptor potential vanilloid 1 (TRPV1) channel on sensory neurons, improving ATP production, vascular function, fatigue resistance, and thus exercise performance. However, the underlying mechanisms of CAP-induced ergogenic effects and fatigue-resistance, remain elusive. To evaluate the potential anti-fatigue effects of CAP, 10 young healthy males performed constant-load cycling exercise time to exhaustion (TTE) trials (85% maximal work rate) after ingestion of placebo (PL; fiber) or CAP capsules in a blinded, counterbalanced, crossover design, while cardiorespiratory responses were monitored. Fatigue was assessed with the interpolated twitch technique, pre-post exercise, during isometric maximal voluntary contractions (MVC). No significant differences (p > 0.05) were detected in cardiorespiratory responses and self-reported fatigue (RPE scale) during the time trial or in TTE (375 ± 26 and 327 ± 36 s, respectively). CAP attenuated the reduction in potentiated twitch (PL: -52 ± 6 vs. CAP: -42 ± 11%, p = 0.037), and tended to attenuate the decline in maximal relaxation rate (PL: -47 ± 33 vs. CAP: -29 ± 68%, p = 0.057), but not maximal rate of force development, MVC, or voluntary muscle activation. Thus, CAP might attenuate neuromuscular fatigue through alterations in afferent signaling or neuromuscular relaxation kinetics, perhaps mediated via the sarco-endoplasmic reticulum Ca2+ ATPase (SERCA) pumps, thereby increasing the rate of Ca2+ reuptake and relaxation.
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Affiliation(s)
- Gaia Giuriato
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, 37134 Verona, Italy; (G.G.); (M.V.)
- Health and Human Physiological Sciences Department, Skidmore College, Saratoga Springs, NY 12866, USA; (A.M.); (E.M.K.V.K.S.)
| | - Massimo Venturelli
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, 37134 Verona, Italy; (G.G.); (M.V.)
- Department of Internal Medicine, University of Utah, Salt Lake City, UT 84132, USA
| | - Alexs Matias
- Health and Human Physiological Sciences Department, Skidmore College, Saratoga Springs, NY 12866, USA; (A.M.); (E.M.K.V.K.S.)
| | - Edgard M. K. V. K. Soares
- Health and Human Physiological Sciences Department, Skidmore College, Saratoga Springs, NY 12866, USA; (A.M.); (E.M.K.V.K.S.)
- Study Group on Exercise and Physical Activity Physiology and Epidemiology, Exercise Physiology Laboratory, Faculty of Physical Education, University of Brasilia—UnB, Brasilia 70910-900, Brazil
| | - Jessica Gaetgens
- Department of Chemistry, Skidmore College, Saratoga Springs, NY 12866, USA; (J.G.); (K.A.F.)
| | - Kimberley A. Frederick
- Department of Chemistry, Skidmore College, Saratoga Springs, NY 12866, USA; (J.G.); (K.A.F.)
| | - Stephen J. Ives
- Health and Human Physiological Sciences Department, Skidmore College, Saratoga Springs, NY 12866, USA; (A.M.); (E.M.K.V.K.S.)
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Aalkjær C, Nilsson H, De Mey JGR. Sympathetic and Sensory-Motor Nerves in Peripheral Small Arteries. Physiol Rev 2020; 101:495-544. [PMID: 33270533 DOI: 10.1152/physrev.00007.2020] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Small arteries, which play important roles in controlling blood flow, blood pressure, and capillary pressure, are under nervous influence. Their innervation is predominantly sympathetic and sensory motor in nature, and while some arteries are densely innervated, others are only sparsely so. Innervation of small arteries is a key mechanism in regulating vascular resistance. In the second half of the previous century, the physiology and pharmacology of this innervation were very actively investigated. In the past 10-20 yr, the activity in this field was more limited. With this review we highlight what has been learned during recent years with respect to development of small arteries and their innervation, some aspects of excitation-release coupling, interaction between sympathetic and sensory-motor nerves, cross talk between endothelium and vascular nerves, and some aspects of their role in vascular inflammation and hypertension. We also highlight what remains to be investigated to further increase our understanding of this fundamental aspect of vascular physiology.
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Affiliation(s)
| | - Holger Nilsson
- Department Physiology, Gothenburg University, Gothenburg, Sweden
| | - Jo G R De Mey
- Deptartment Pharmacology and Personalized Medicine, Maastricht University, Maastricht, The Netherlands
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Andrade F, Rangel-Sandoval C, Rodríguez-Hernández A, López-Dyck E, Elizalde A, Virgen-Ortiz A, Bonales-Alatorre E, Valencia-Cruz G, Sánchez-Pastor E. Capsaicin Causes Vasorelaxation of Rat Aorta through Blocking of L-type Ca 2+ Channels and Activation of CB 1 Receptors. Molecules 2020; 25:molecules25173957. [PMID: 32872656 PMCID: PMC7504815 DOI: 10.3390/molecules25173957] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 08/21/2020] [Accepted: 08/29/2020] [Indexed: 01/21/2023] Open
Abstract
The aim of this work was to determine whether Capsaicin may exert a vascular regulation through the activation of CB1 and/or CB2 receptors causing vasorelaxation in the rat aorta. Our results show the location of TRPV1 mainly in the endothelial and smooth muscle cells membrane. Nevertheless, Capsaicin caused vasorelaxation of this artery through a mechanism independent of TRPV1, since the specific antagonists Capsazepine and SB-366791 did not block the effect of Capsaicin. Because the significant expression of CB1 and CB2 receptors has been previously reported in the rat aorta, we used antagonists for these two receptors prior to the addition of Capsaicin. In these experiments, we found that the inhibition of CB1 using AM281, decreases the vasorelaxant effect caused by Capsaicin. On the other hand, the vasorelaxant effect is not altered in the presence of the CB2 receptor antagonist AM630. Furthermore, a partial decrease of the effect of Capsaicin was also seen when L-type calcium channels are blocked. A complete block of Capsaicin-induced vasorelaxation was achieved using a combination of Verapamil and AM281. In accordance to our results, Capsaicin-induced vasorelaxation of the rat aorta is neither dependent of TRPV1 or CB2 receptors, but rather it is strongly suggested that a tandem mechanism between inactivation of L-type calcium channels and the direct activation of CB1 receptors is involved. These findings are supported by CB1 docking simulation which predicted a binding site on CB1 receptors for Capsaicin.
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Affiliation(s)
- Felipa Andrade
- National Technological Institute of Mexico/Technological Institute of Colima, Avenida Tecnológico No. 1, CP 28976 Villa de Álvarez, Colima, Mexico;
| | - Cinthia Rangel-Sandoval
- University Center for Biomedical Research, University of Colima, Apdo. Postal No. 11, CP 28040 Colima, Colima, Mexico; (C.R.-S.); (A.E.); (A.V.-O.); (E.B.-A.); (G.V.-C.)
| | | | - Evelyn López-Dyck
- State University of Sonora, Navojoa Academic Unit. Blvd. Manlio Fabio Beltrones 810, CP 85875 Navojoa, Sonora, Mexico;
| | - Alejandro Elizalde
- University Center for Biomedical Research, University of Colima, Apdo. Postal No. 11, CP 28040 Colima, Colima, Mexico; (C.R.-S.); (A.E.); (A.V.-O.); (E.B.-A.); (G.V.-C.)
| | - Adolfo Virgen-Ortiz
- University Center for Biomedical Research, University of Colima, Apdo. Postal No. 11, CP 28040 Colima, Colima, Mexico; (C.R.-S.); (A.E.); (A.V.-O.); (E.B.-A.); (G.V.-C.)
| | - Edgar Bonales-Alatorre
- University Center for Biomedical Research, University of Colima, Apdo. Postal No. 11, CP 28040 Colima, Colima, Mexico; (C.R.-S.); (A.E.); (A.V.-O.); (E.B.-A.); (G.V.-C.)
| | - Georgina Valencia-Cruz
- University Center for Biomedical Research, University of Colima, Apdo. Postal No. 11, CP 28040 Colima, Colima, Mexico; (C.R.-S.); (A.E.); (A.V.-O.); (E.B.-A.); (G.V.-C.)
| | - Enrique Sánchez-Pastor
- University Center for Biomedical Research, University of Colima, Apdo. Postal No. 11, CP 28040 Colima, Colima, Mexico; (C.R.-S.); (A.E.); (A.V.-O.); (E.B.-A.); (G.V.-C.)
- Correspondence: ; Tel.: +52 (312) 31-611-29
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Ives SJ, Park SY, Kwon OS, Gifford JR, Andtbacka RHI, Hyngstrom JR, Richardson RS. TRPV 1 channels in human skeletal muscle feed arteries: implications for vascular function. Exp Physiol 2017; 102:1245-1258. [PMID: 28681979 DOI: 10.1113/ep086223] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Accepted: 06/30/2017] [Indexed: 12/20/2022]
Abstract
NEW FINDINGS What is the central question of this study? We sought to determine whether human skeletal muscle feed arteries (SFMAs) express TRPV1 channels and what role they play in modulating vascular function. What is the main finding and its importance? Human SMFAs do express functional TRPV1 channels that modulate vascular function, specifically opposing α-adrenergic receptor-mediated vasocontraction and potentiating vasorelaxation, in an endothelium-dependent manner, as evidenced by the α1 -receptor-mediated responses. Thus, the vasodilatory role of TRPV1 channels, and their ligand capsaicin, could be a potential therapeutic target for improving vascular function. Additionally, given the 'sympatholytic' effect of TRPV1 activation and known endogenous activators (anandamide, reactive oxygen species, H+ , etc.), TRPV1 channels might contribute to functional sympatholysis during exercise. To examine the role of the transient receptor potential vanilloid type 1 (TRPV1 ) ion channel in the vascular function of human skeletal muscle feed arteries (SMFAs) and whether activation of this heat-sensitive receptor could be involved in modulating vascular function, SMFAs from 16 humans (63 ± 5 years old, range 41-89 years) were studied using wire myography with capsaicin (TRPV1 agonist) and without (control). Specifically, phenylephrine (α1 -adrenergic receptor agonist), dexmedetomidine (α2 -adrenergic receptor agonist), ACh and sodium nitroprusside concentration-response curves were established to assess the role of TRPV1 channels in α-receptor-mediated vasocontraction as well as endothelium-dependent and -independent vasorelaxation, respectively. Compared with control conditions, capsaicin significantly attenuated maximal vasocontraction in response to phenylephrine [control, 52 ± 8% length-tensionmax (LTmax ) and capsaicin, 21 ± 5%LTmax ] and dexmedetomidine (control, 29 ± 12%LTmax and capsaicin, 2 ± 3%LTmax ), while robustly enhancing maximal vasorelaxation with ACh (control, 78 ± 8% vasorelaxation and capsaicin, 108 ± 13% vasorelaxation) and less clearly enhancing the sodium nitroprusside response. Denudation of the endothelium greatly attenuated the maximal ACh-induced vasorelaxation equally in the control and capsaicin conditions (∼17% vasorelaxation) and abolished the attenuating effect of capsaicin on the maximal phenylephrine response (denuded + capsaicin, 61 ± 20%LTmax ). Immunohistochemistry identified a relatively high density of TRPV1 channels in the endothelium compared with the smooth muscle of the SMFAs, but because of the far greater volume of smooth muscle, total TRPV1 protein content was not significantly attenuated by denudation. Thus, SMFAs ubiquitously express functional TRPV1 channels, which alter vascular function, in terms of α1 -receptors, in a predominantly endothelium-dependent manner, conceivably contributing to the functional sympatholysis and unveiling a therapeutic target.
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Affiliation(s)
- Stephen J Ives
- Geriatric Research, Education and Clinical Center, George E. Whalen VA Medical Center, Salt Lake City, UT, USA.,Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, UT, USA.,Department of Health and Exercise Sciences, Skidmore College, Saratoga Springs, NY, USA
| | - Song Young Park
- Geriatric Research, Education and Clinical Center, George E. Whalen VA Medical Center, Salt Lake City, UT, USA
| | - Oh Sung Kwon
- Geriatric Research, Education and Clinical Center, George E. Whalen VA Medical Center, Salt Lake City, UT, USA.,Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, UT, USA
| | - Jayson R Gifford
- Geriatric Research, Education and Clinical Center, George E. Whalen VA Medical Center, Salt Lake City, UT, USA.,Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, UT, USA
| | - Robert H I Andtbacka
- Department of Surgery, Huntsman Cancer Hospital, University of Utah, Salt Lake City, UT, USA
| | - John R Hyngstrom
- Department of Surgery, Huntsman Cancer Hospital, University of Utah, Salt Lake City, UT, USA
| | - Russell S Richardson
- Geriatric Research, Education and Clinical Center, George E. Whalen VA Medical Center, Salt Lake City, UT, USA.,Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, UT, USA.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA
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Ivic I, Solymar M, Pakai E, Rumbus Z, Pinter E, Koller A, Garami A. Transient Receptor Potential Vanilloid-1 Channels Contribute to the Regulation of Acid- and Base-Induced Vasomotor Responses. J Vasc Res 2016; 53:279-290. [PMID: 27923234 DOI: 10.1159/000452414] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 10/08/2016] [Indexed: 11/19/2022] Open
Abstract
pH changes can influence local blood flow, but the mechanisms of how acids and bases affect vascular tone is not fully clarified. Transient receptor potential vanilloid-1 (TRPV1) channels are expressed in vessels and can be activated by pH alterations. Thus, we hypothesized that TRPV1 channels are involved in the mediation of vascular responses to acid-base changes. Vasomotor responses to HCl, NaOH, and capsaicin were measured in isolated murine carotid and tail skin arteries. The function of TRPV1 was blocked by either of three approaches: Trpv1 gene disruption, pharmacological blockade with a TRPV1 antagonist (BCTC), and functional impairment of mainly neural TRPV1 channels (desensitization). In each artery type of control mice, HCl caused relaxation but NaOH contraction, and both responses were augmented after genetic or pharmacological TRPV1 blockade. In arteries of TRPV1-desensitized mice, HCl-induced relaxation did not differ from controls, whereas NaOH-induced contraction was augmented. All three types of TRPV1 blockade had more pronounced effects in carotid than in tail skin arteries. We conclude that TRPV1 channels limit the vasomotor responses to changes in pH. While base-induced arterial contraction is regulated primarily by neural TRPV1 channels, acid-induced arterial relaxation is modulated by TRPV1 channels located on nonneural vascular structures.
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Affiliation(s)
- Ivan Ivic
- Institute for Translational Medicine, Medical School, University of Pecs, Pecs, Hungary
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Mechanisms of vasorelaxation induced by the cannabidiol analogue compound O-1602 in the rat small mesenteric artery. Eur J Pharmacol 2015; 765:107-14. [DOI: 10.1016/j.ejphar.2015.08.021] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2015] [Revised: 08/16/2015] [Accepted: 08/17/2015] [Indexed: 11/20/2022]
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Reduced endothelium-dependent relaxation to anandamide in mesenteric arteries from young obese Zucker rats. PLoS One 2013; 8:e63449. [PMID: 23667622 PMCID: PMC3646748 DOI: 10.1371/journal.pone.0063449] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Accepted: 04/03/2013] [Indexed: 11/21/2022] Open
Abstract
Impaired vascular function, manifested by an altered ability of the endothelium to release endothelium-derived relaxing factors and endothelium-derived contracting factors, is consistently reported in obesity. Considering that the endothelium plays a major role in the relaxant response to the cannabinoid agonist anandamide, the present study tested the hypothesis that vascular relaxation to anandamide is decreased in obese rats. Mechanisms contributing to decreased anandamide-induced vasodilation were determined. Resistance mesenteric arteries from young obese Zucker rats (OZRs) and their lean counterparts (LZRs) were used. Vascular reactivity was evaluated in a myograph for isometric tension recording. Protein expression and localization were analyzed by Western blotting and immunofluorescence, respectively. Vasorelaxation to anandamide, acetylcholine, and sodium nitroprusside, as well as to CB1, CB2, and TRPV1 agonists was decreased in endothelium-intact mesenteric arteries from OZRs. Incubation with an AMP-dependent protein kinase (AMPK) activator or a fatty acid amide hydrolase inhibitor restored anandamide-induced vascular relaxation in OZRs. CB1 and CB2 receptors protein expression was decreased in arteries from OZRs. Incubation of mesenteric arteries with anandamide evoked endothelial nitric oxide synthase (eNOS), AMPK and acetyl CoA carboxylase phosphorylation in LZRs, whereas it decreased phosphorylation of these proteins in OZRs. In conclusion, obesity decreases anandamide-induced relaxation in resistance arteries. Decreased cannabinoid receptors expression, increased anandamide degradation, decreased AMPK/eNOS activity as well as impairment of the response mediated by TRPV1 activation seem to contribute to reduce responses to cannabinoid agonists in obesity.
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Michel-Monigadon D, Steffens S, Molica F, Mach F, Montecucco F. Update on the endocannabinoid-mediated regulation of gelatinase release in arterial wall physiology and atherosclerotic pathophysiology. Expert Rev Cardiovasc Ther 2012; 10:1481-6. [PMID: 23253273 DOI: 10.1586/erc.12.145] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Endocannabinoids are endogenous bioactive lipids ubiquitously distributed in several tissues (e.g., brain, adipose tissue, liver, heart and arterial vessels), which play a crucial role in atherosclerosis. Endocannabinoids have been shown to promote cell homeostasis and modulate inflammatory bioactivities mainly via the binding to transmembrane receptors (called cannabinoid type 1 and cannabinoid type 2 receptors, respectively). Although other cannabinoid receptors have been recently identified and shown to play a crucial role in cardiovascular pathophysiology, so far, the pharmacological targeting of both cannabinoid type 1 and cannabinoid type 2 receptors has been described as a promising therapeutic target in atherogenesis and associated inflammatory processes. In particular, endocannabinoids have been shown to modulate the release and activation of matrix degrading enzymes (i.e., matrix metalloproteinases [MMPs]) increasing intraplaque vulnerability. In this article the authors describe the pivotal regulatory activity of the endocannabinoid system on gelatinase (MMP-2 and -9) bioactivity in the arterial wall physiology and pathophysiology.
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Affiliation(s)
- Delphine Michel-Monigadon
- Division of Cardiology, Faculty of Medicine, Geneva University Hospitals, avenue de la Roseraie 64, 1211 Geneva 4, Switzerland
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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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Ohanyan VA, Guarini G, Thodeti CK, Talasila PK, Raman P, Haney RM, Meszaros JG, Damron DS, Bratz IN. Endothelin-mediated in vivo pressor responses following TRPV1 activation. Am J Physiol Heart Circ Physiol 2011; 301:H1135-42. [DOI: 10.1152/ajpheart.00082.2011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Transient receptor potential vanilliod 1 (TRPV1) channels have recently been postulated to play a role in the vascular complications/consequences associated with diabetes despite the fact that the mechanisms through which TRPV1 regulates vascular function are not fully known. Accordingly, our goal was to define the mechanisms by which TRPV1 channels modulate vascular function and contribute to vascular dysfunction in diabetes. We subjected mice lacking TRPV1 [TRPV1(−/−)], db/ db, and control C57BLKS/J mice to in vivo infusion of the TRPV1 agonist capsaicin or the α-adrenergic agonist phenylephrine (PE) to examine the integrated circulatory actions of TRPV1. Capsaicin (1, 10, 20, and 100 μg/kg) dose dependently increased MAP in control mice (5.7 ± 1.6, 11.7 ± 2.1, 25.4 ± 3.4, and 51.6 ± 3.9%), which was attenuated in db/db mice (3.4 ± 2.1, 3.9 ± 2.1, 7.0 ± 3.3, and 17.9 ± 6.2%). TRPV1(−/−) mice exhibited no changes in MAP in response to capsaicin, suggesting the actions of this agonist are specific to TRPV1 activation. Immunoblot analysis revealed decreased aortic TRPV1 protein expression in db/db compared with control mice. Capsaicin-induced responses were recorded following inhibition of endothelin A and B receptors (ETA /ETB). Inhibition of ETA receptors abolished the capsaicin-mediated increases in MAP. Combined antagonism of ETA and ETB receptors did not further inhibit the capsaicin response. Cultured endothelial cell exposure to capsaicin increased endothelin production as shown by an endothelin ELISA assay, which was attenuated by inhibition of TRPV1 or endothelin-converting enzyme. TRPV1 channels contribute to the regulation of vascular reactivity and MAP via production of endothelin and subsequent activation of vascular ETA receptors. Impairment of TRPV1 channel function may contribute to vascular dysfunction in diabetes.
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Affiliation(s)
- Vahagn A. Ohanyan
- Department of Integrative Medical Sciences, Northeastern Ohio Universities Colleges of Medicine and Pharmacy, Rootstown, Ohio; and
| | - Giacinta Guarini
- Department of Integrative Medical Sciences, Northeastern Ohio Universities Colleges of Medicine and Pharmacy, Rootstown, Ohio; and
| | - Charles K. Thodeti
- Department of Integrative Medical Sciences, Northeastern Ohio Universities Colleges of Medicine and Pharmacy, Rootstown, Ohio; and
| | - Phani K. Talasila
- Department of Integrative Medical Sciences, Northeastern Ohio Universities Colleges of Medicine and Pharmacy, Rootstown, Ohio; and
| | - Priya Raman
- Department of Integrative Medical Sciences, Northeastern Ohio Universities Colleges of Medicine and Pharmacy, Rootstown, Ohio; and
| | - Rebecca M. Haney
- Department of Integrative Medical Sciences, Northeastern Ohio Universities Colleges of Medicine and Pharmacy, Rootstown, Ohio; and
| | - J. Gary Meszaros
- Department of Integrative Medical Sciences, Northeastern Ohio Universities Colleges of Medicine and Pharmacy, Rootstown, Ohio; and
| | - Derek S. Damron
- Department of Biological Sciences, Kent State University, Kent, Ohio
| | - Ian N. Bratz
- Department of Integrative Medical Sciences, Northeastern Ohio Universities Colleges of Medicine and Pharmacy, Rootstown, Ohio; and
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Abstract
PURPOSE The generation of hyperpolarising vasorelaxant endothelial cytochrome P450 epoxygenase (CYP)-derived metabolites of arachidonic may provide beneficial effects for the treatment of cardiovascular diseases in which the bioavailability of NO is impaired. The cannabinoid methanandamide has vasodilatory properties linked to hyperpolarisation. The aim of the present work was to investigate the vasorelaxant effects of methanandamide in rat aorta, focusing on the role of cytochrome P450 pathway. METHODS Changes in isometric tension in response to a cumulative concentration-response curve of methanandamide (1 nM-100 μM) were recorded in aortic rings from male Wistar rats. The involvement of cannabinoid receptors, endothelial nitric oxide (NO)-, prostacyclin- and some hyperpolarising-mediated pathways were investigated. The activation of large-conductance Ca(2+)-activated K(+) (BKCa) channels have also been evaluated. RESULTS Methanandamide provoked an endothelium-dependent vasorelaxation in rat aorta, reaching a maximal effect (Rmax) of 67% ± 2.6%. This vasorelaxation was clearly inhibited by the combination of CB(1) and CB(2) cannabinoid antagonists (Rmax: 21.6% ± 1.3%) and by the combination of guanylate cyclase and CYP inhibitors (Rmax: 16.7% ± 1.1%). The blockade induced separately by guanylate cyclase (31.3% ± 2.8%) or CYP (36.3% ± 6.6%) inhibitors on methanandamide vasorelaxation was not significantly modified by either CB(1) or CB(2) inhibition. BKCa channels inhibition caused a partial and significant inhibition of the methanandamide vasorelaxation (Rmax: 39.9% ± 3.3%). CONCLUSIONS Methanandamide endothelium-dependent vasorelaxation is mediated by CB(1) and CB(2) cannabinoid receptors. The NO- and CYP-mediated pathways contribute in a concurrent manner in this vascular effect. Stimulation of both cannabinoid receptor subtypes is indistinctly linked to NO or CYP routes to cause vasorelaxation.
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12
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Haddock RE, Hill CE. Sympathetic overdrive in obesity involves purinergic hyperactivity in the resistance vasculature. J Physiol 2011; 589:3289-307. [PMID: 21576274 DOI: 10.1113/jphysiol.2011.207944] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
While a close correlation exists in obese humans between sympathetic, adrenergic hyperactivity and structural and functional organ damage, a role for the co-transmitter, ATP, in vascular function remains unexplored. We therefore studied sympathetic nerve-mediated responses of pressurised small mesenteric arteries from control and obese rats. Diet-induced obesity significantly increased the amplitude of vasoconstriction to transmural nerve stimulation (1-10 Hz; P <0.05). At 1 and 5 Hz, both adrenergic and purinergic responses were significantly augmented, while only the purinergic component was increased at 10 Hz (P <0.05). Nerve stimulation at 1 Hz evoked contractions and underlying excitatory junction potentials (EJPs), which were both significantly increased in amplitude during obesity (P <0.05) and abolished by αβ-methylene ATP (1 μM; desensitises purinergic receptors). The rise time and rate of decay of these EJPs were significant decreased (P <0.05), without change in resting membrane potential. Amplitude and frequency of spontaneous EJPs and the density of perivascular sympathetic nerves were also significantly increased (P <0.05). Inhibition of sensory neurotransmitter release (capsaicin; 10 μM) significantly increased the amplitude of nerve-mediated contraction (P <0.05), with a greater effect in control than obese animals, although the density of sensory nerves was unaffected by obesity. We demonstrate that sympathetic nerve-mediated vasoconstriction is enhanced by diet-induced obesity due to upregulation of purinergic, in addition to adrenergic, neurotransmission. Changes result from increased perivascular sympathetic innervation and release of ATP. We conclude that augmented sympathetic control of vasoconstriction induced by obesity could contribute directly to hypertension and global organ damage. A decrease in sensitivity to sensory vasodilatory neurotransmitters may also affect these processes.
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Affiliation(s)
- Rebecca E Haddock
- Department of Neuroscience, John Curtin School of Medical Research, Australian National University, GPO Box 334, Canberra, ACT, 0200, Australia.
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Chronic Treatment With the Cannabinoid 1 Antagonist Rimonabant Altered Vasoactive Cyclo-oxygenase-Derived Products on Arteries From Obese Zucker Rats. J Cardiovasc Pharmacol 2010; 56:560-9. [DOI: 10.1097/fjc.0b013e3181f7141a] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Hypotension induced by activation of the transient receptor potential vanilloid 4 channels: role of Ca2+-activated K+ channels and sensory nerves. J Hypertens 2010; 28:102-10. [PMID: 19996988 DOI: 10.1097/hjh.0b013e328332b865] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To examine the mechanisms involved in hypotension induced by transient receptor potential vanilloid 4 (TRPV4) activation. METHODS Wistar rats were given 50 mg/kg capsaicin subcutaneously 1-2 days postnatally to cause degeneration of capsaicin-sensitive sensory nerves. Vehicle was given to the corresponding newborn rats that formed the control group. After being weaned, male rats were picked for further investigation. At the age of 8 weeks, mean arterial pressure and its response to 4alpha-phorbol 12,13-didecanoate [4alpha-PDD, a selective TRPV4 activator, 2.5 mg/kg, intravenous(ly) or i.v.] with or without CGRP8-37 (1 mg/kg per min, i.v.), an antagonist of calcitonin gene-related peptide (CGRP, a potent vasodilator released from sensory nerves), in vehicle or capsaicin-pretreated rats anesthetized with sodium pentobarbital [50 mg/kg, intraperitoneal(ly)] were monitored to observe the contributions of neuropeptides released from sensory nerves to the 4alpha-PDD-induced hypotension. To detect the roles of various vasodilating factors released by vascular endothelium in the hypotensive effect induced by TRPV4 activation, the corresponding inhibitors/blockers, including indomethacin (a cyclooxygenase inhibitor, 10 mg/kg, i.v.), Nomega-nitro-L-arginine (L-NA, a nitric oxide synthase inhibitor, 20 mg/kg, i.v.), apamin [a blocker of small conductance Ca2+-activated K+ (MaxiK) channels, 50 microg/kg, i.v.] combined with charybdotoxin (a blocker of intermediate and large conductance MaxiK channels, 50 microg/kg, i.v.), were used at various time before 4alpha-PDD injection. Plasma CGRP and substance P levels of rats before or after administration were measured using the corresponding radioimmunoassays. At last, immunohistochemistry stainings were performed to observe expression of TRPV4/CGRP/MaxiK in mesenteric resistance arteries and sensory neurons/nerve fibers. RESULTS Intravenous administration of 4alpha-PDD produced remarkable hypotension in vehicle-pretreated rats. The depressor effect was attenuated by degeneration of capsaicin-sensitive sensory nerves (P < 0.05) or administration of CGRP8-37 (P < 0.05). In both vehicle and capsaicin-pretreated rats, the combined administration of apamin and charybdotoxin markedly reduced the 4alpha-PDD-induced hypotensive effect (P < 0.05), but i.v. administration of indomethacin and Nomega-nitro-L-arginine did not produce the similar effect. Intravenous administration of 4alpha PDD increased plasma CGRP but not substance P levels in vehicle-pretreated rats only (P < 0.05), which was not affected by indomethacin, Nomega-nitro-L-arginine, or apamin and charybdotoxin. Immunohistochemistry staining showed that TRPV4 colocalized with MaxiK channels in endothelium of mesenteric resistance arteries and with CGRP in sensory neurons/nerve fibers. CONCLUSION Our data show that the hypotensive effect induced by TRPV4 activation attributes to, at least in part, activation of MaxiK channels and CGRP receptors upon CGRP release from sensory nerves.
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Mingorance C, Alvarez de Sotomayor M, Jiménez-Palacios FJ, Callejón Mochón M, Casto C, Marhuenda E, Herrera MD. Effects of chronic treatment with the CB1 antagonist, rimonabant on the blood pressure, and vascular reactivity of obese Zucker rats. Obesity (Silver Spring) 2009; 17:1340-7. [PMID: 19553924 DOI: 10.1038/oby.2009.20] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Rimonabant (RM) is a cannabinoid CB1 receptor antagonist useful in the treatment of obesity associated cardiovascular risk factors. Since cannabinoids are vasoactive compounds, the aim of this study is to evaluate the effect of chronic treatment with RM on systolic blood pressure (SBP), and endothelial and vascular reactivity. Obese Zucker rats (OZRs) and their lean counterparts were orally treated during 20 weeks with either RM (10 mg/kg/day). Endothelial and vascular function was assessed in aorta and small mesenteric arteries (SMAs) by concentration response curves to acetylcholine (ACh) and phenylephrine (Phe), respectively. Participation of nitric oxide (NO) was evaluated by incubation with the NO synthase (NOS) inhibitor N(G)-nitro-l-arginine methyl ester (L-NAME) and cyclooxygenase (COX)-derived products involvement was analyzed by incubation with indomethacin (INDO). Plasma lipid profile, insulin and adiponectin were also analyzed. Sympathetic activity was evaluated by urinary excretion of noradrenaline. As expected, RM decreased body weight gain and enhanced adiponectin concentration. Insulin resistance and sympathetic activity were also decreased. The increase in SBP observed in OZRs was reduced by treatment with RM. Aortae and SMAs from OZRs exhibited lower contractile response to Phe, being this effect prevented by RM administration. Although ACh-induced response and NO participation remained unaltered with obesity, enhanced COX-derived constrictor products were found in OZRs. RM treatment neither altered endothelium-dependent relaxation nor L-NAME-sensitive component of the response. Nevertheless, it was able to regulate COX-derived vasoactive products participation. Those effects may contribute to explain some of the cardiovascular protective actions elicited by this drug.
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Affiliation(s)
- Carmen Mingorance
- Department of Pharmacology, Faculty of Pharmacy, University of Seville, Seville, Spain
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Vural IM, Ozturk GS, Sarioglu Y. Functional Characterization of Nonadrenergic Noncholinergic Neurotransmitter Release via Endocannabinoids: An in Vitro Study in Rabbit Corpus Cavernosum. J Sex Med 2009; 6:717-29. [DOI: 10.1111/j.1743-6109.2008.01003.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Transient receptor potential vanilloid channels in hypertension, inflammation, and end organ damage: an imminent target of therapy for cardiovascular disease? Curr Opin Cardiol 2008; 23:356-63. [PMID: 18520720 DOI: 10.1097/hco.0b013e32830460ad] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
PURPOSE OF REVIEW The possible role of several neurohormonal factors in pathogenesis of hypertension has been studied extensively both in humans and in experimental animal models. However, controversial data from some previous studies are indecisive and call for reassessment and development of new targets. This mini-review presents some of the most recent findings about the role of transient receptor potential vanilloid type 1 channels in the development of hypertension and its pathology. RECENT FINDINGS The transient receptor potential vanilloid type 1, channel activated by novel endovanilloids or altered pH, temperature, and/or local hemodynamics, may serve as a distinct molecular sensor detecting sodium and water balance and may play a role in preventing salt-induced hypertension and tissue damage. Impairment of the function of the transient receptor potential vanilloid type 1 channels may contribute to increased salt sensitivity, inflammation, and end organ damage. SUMMARY Emerging evidence indicates that the transient receptor potential vanilloid type 1 channel plays a key role in cardiovascular health and disease by acting as a sensor and regulator of cardiovascular homeostasis and a protector against cardiovascular injury. Given the huge population who suffers from cardiovascular disease, the study of the transient receptor potential vanilloid channels may improve our understanding of pathogenesis of several common cardiovascular disorders and may lead to the development of therapy for hypertension, inflammation, and organ damage.
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Kark T, Bagi Z, Lizanecz E, Pásztor ET, Erdei N, Czikora A, Papp Z, Edes I, Pórszász R, Tóth A. Tissue-specific regulation of microvascular diameter: opposite functional roles of neuronal and smooth muscle located vanilloid receptor-1. Mol Pharmacol 2008; 73:1405-12. [PMID: 18256211 DOI: 10.1124/mol.107.043323] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The transient receptor potential type V1 channel (vanilloid receptor 1, TRPV1) is a Ca(2+)-permeable nonspecific cation channel activated by various painful stimuli including ischemia. We hypothesized that TRPV1 is expressed in the arterioles and is involved in the regulation of microvascular tone. We found that TRPV1 stimulation by capsaicin (intra-arterial administration) of the isolated, perfused right hind limb of the rat increased vascular resistance (by 98 +/- 21 mm Hg at 10 mug) in association with decreased skeletal muscle perfusion and elevation of skin perfusion (detected by dual-channel laser Doppler flowmetry). Denervation of the hind limb did not affect capsaicin-evoked changes in vascular resistance and tissue perfusion in the hind limb but reduced the elevation of perfusion in the skin. In isolated, pressurized skeletal (musculus gracilis) muscle arterioles (diameter, 147 +/- 35 mum), capsaicin had biphasic effects: at lower concentrations, capsaicin (up to 10 nM) evoked dilations (maximum, 32 +/- 13%), whereas higher concentrations (0.1-1 muM) elicited substantial constrictions (maximum, 66 +/- 7%). Endothelium removal or inhibition of nitric-oxide synthase abolished capsaicin-induced dilations but did not affect arteriolar constriction. Expression of TRPV1 was detected by reverse transcriptase-polymerase chain reaction in the aorta and in cultured rat aortic vascular smooth muscle cells (A7r5). Immunohistochemistry revealed expression primarily in the smooth muscle layers of the gracilis arteriole. These data demonstrate the functional expression of TRPV1 in vascular smooth muscle cells mediating vasoconstriction of the resistance arteries. Because of the dual effects of TRPV1 stimulation on the arteriolar diameter (dilation in skin, constriction in skeletal muscle), we propose that TRPV1 ligands represent drug candidates for tissue-specific modulation of blood distribution.
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Affiliation(s)
- Tamás Kark
- Division of Clinical Physiology, Institute of Cardiology, Medical and Health Science Center, University of Debrecen, 22 Moricz Zs krt, 4032, Debrecen, Hungary
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Li J, Wang DH. Increased GFR and renal excretory function by activation of TRPV1 in the isolated perfused kidney. Pharmacol Res 2008; 57:239-46. [PMID: 18329285 DOI: 10.1016/j.phrs.2008.01.011] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2007] [Revised: 01/15/2008] [Accepted: 01/29/2008] [Indexed: 11/16/2022]
Abstract
To test the hypothesis that activation of the transient receptor potential vanilloid type 1 (TRPV1) channels leads to natriuresis and diuresis via an increase in glomerular filtration rate (GFR), recirculating Krebs-Henseleit buffer added with inulin was perfused in the isolated perfused kidney of male Wistar rat at a constant flow, and perfusion pressures (PPs) were pre-adjusted to three different levels ( approximately 100, approximately 150, and approximately 190mmHg) with phenylephrine. Capsaicin (Cap), a selective TRPV1 agonist, was perfused in the presence or absence of capsazepine (Capz), a selective TRPV1 antagonist, CGRP(8-37), a selective calcitonin gene-related peptide (CGRP) receptor antagonist, or spantide II (Spa), a selective substance P (SP) receptor antagonist. At the higher (150 and 190mmHg) but not baseline (100mmHg) PP levels, Cap at 10microM significantly decreased PP and increased GFR, urine flow rate (UFR) and Na+ excretion (UNaV). At the highest (190mmHg) PP level, Cap (2, 10, 30microM) dose-dependently decreased PP and increased GFR, UFR, UNaV, and the release of CGRP and SP. Capz or CGRP(8-37) combined with Spa fully blocked the effect of Cap on PP, GFR, UFR, UNaV, and the release of CGRP and SP. In conclusion, activation of TRPV1 in the isolated kidney decreases renal PP and increases GFR and water/sodium excretion possibly via simultaneous activation of CGRP and SP receptors upon their enhanced release, suggesting that TRPV1 plays a key role in modulating renal hemodynamics and excretory function.
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Affiliation(s)
- Jianping Li
- Department of Medicine, Neuroscience Program, and Cell and Molecular Biology Program, Michigan State University, East Lansing, MI 48824, USA
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McDougall JJ, Yu V, Thomson J. In vivo effects of CB2 receptor-selective cannabinoids on the vasculature of normal and arthritic rat knee joints. Br J Pharmacol 2007; 153:358-66. [PMID: 17982474 DOI: 10.1038/sj.bjp.0707565] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND AND PURPOSE Cannabinoids (CBs) are known to be vasoactive and to regulate tissue inflammation. The present study examined the in vivo vasomotor effects of the CB2 receptor agonists JWH015 and JWH133 in rat knee joints. The effect of acute and chronic joint inflammation on CB2 receptor-mediated responses was also tested. EXPERIMENTAL APPROACH Blood flow was assessed in rat knee joints by laser Doppler imaging both before and following topical administration of CB2 receptor agonists. Vasoactivity was measured in normal, acute kaolin/carrageenan inflamed and Freund's complete adjuvant chronically inflamed knees. KEY RESULTS In normal animals, JWH015 and JWH133 caused a concentration-dependent increase in synovial blood flow which in the case of JWH133 was blocked by the selective CB2 receptor antagonist AM630 as well as the transient receptor potential vanilloid-1 (TRPV1) antagonist SB366791. The vasodilator effect of JWH133 was significantly attenuated in both acute and chronically inflamed knees. Given alone, AM630 had no effect on joint blood flow. CONCLUSION AND IMPLICATIONS In normal joints, the cannabinomimetic JWH133 causes hyperaemia via a CB2 and TRPV1 receptor mechanism. During acute and chronic inflammation, however, this vasodilatatory response is significantly attenuated.
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Affiliation(s)
- J J McDougall
- Department of Physiology & Biophysics, University of Calgary, Calgary, Alberta, Canada.
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Rubino T, Realini N, Castiglioni C, Guidali C, Viganó D, Marras E, Petrosino S, Perletti G, Maccarrone M, Di Marzo V, Parolaro D. Role in anxiety behavior of the endocannabinoid system in the prefrontal cortex. Cereb Cortex 2007; 18:1292-301. [PMID: 17921459 DOI: 10.1093/cercor/bhm161] [Citation(s) in RCA: 202] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In the present study we explored with a multidisciplinary approach, the role of anandamide (AEA) in the modulation of anxiety behavior at the level of the prefrontal cortex (PFC). Low doses of the metabolically stable AEA analog, methanandamide, microinjected into the PFC, produced an anxiolytic-like response in rats, whereas higher doses induced anxiety-like behaviors. Pretreatment with the selective antagonist of CB1 or TRPV1 receptors (AM251 and capsazepine, respectively) suggested that the anxiolytic effect evoked by AEA might be due to the interaction with the CB1 cannabinoid receptor, whereas vanilloid receptors seem to be involved in AEA anxiogenic action. When AEA contents in the PFC were increased by microinjecting the selective inhibitor of fatty acid amide hydrolase (FAAH), URB597, we observed an anxiolytic response only at low doses of the compound and no effect or even an anxiogenic profile at higher doses. In line with this, a marked decrease of AEA levels in the PFC, achieved by lentivirus-mediated local overexpression of FAAH, produced an anxiogenic response. These findings support an anxiolytic role for physiological increases in AEA in the PFC, whereas more marked increases or decreases of this endocannabinoid might lead to an anxiogenic response due to TRPV1 stimulation or the lack of CB1 activation, respectively.
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Affiliation(s)
- T Rubino
- DBSF, Pharmacology Section and Center of Neuroscience, University of Insubria, via A. da Giussano 10, 21052 Busto Arsizio (VA), Italy
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Legros E, Tirapelli CR, Carrier E, Brochu I, Fournier A, D'Orléans-Juste P. Characterization of the non-adrenergic/non-cholinergic response to perivascular nerve stimulation in the double-perfused mesenteric bed of the mouse. Br J Pharmacol 2007; 152:1049-59. [PMID: 17906682 PMCID: PMC2095099 DOI: 10.1038/sj.bjp.0707475] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND AND PURPOSE Calcitonin gene-related peptide (CGRP), a capsaicin-sensitive neuromodulator of splanchnic vascular tone in several animal species, remains poorly investigated in mouse models. We therefore assessed whether endogenous CGRP is a non-adrenergic/non-cholinergic (NANC) neuromodulator in the mesenteric vascular bed of the mouse. EXPERIMENTAL APPROACH Arterial and venous changes in perfusion pressure in response to perivascular nerve stimulation (PNS) were monitored in the mouse mesenteric bed under basal conditions or precontracted with KCl (artery) or U46619 (vein) in circuits pretreated with guanethidine, atropine, indomethacin and prazosin. Arterial responses to NANC were also characterized with a CGRP1 antagonist, halphaCGRP8-37. Finally, the PNS-induced release of arterial CGRP was measured by enzyme immunoassay. KEY RESULTS HalphaCGRP8-37 enhanced PNS-induced arterial increases in perfusion pressure under basal tone. PNS-induced stimulation of NANC triggered an halphaCGRP8-37 or capsaicin- sensitive reduction in perfusion pressure of the pre-contracted arterial bed only. Chemical removal of the endothelium inhibited PNS- and halphaCGRP- induced reduction in perfusion pressure in the arterial mesenteric bed. Responses to NANC nerves were reduced by guanylate and adenylate cyclase inhibitors (1H-[1,2,4]oxadiazole[4,3-a] quinoxalin-1-one (ODQ)) and [9-(tetrahydro-2-furanyl)-9H-purin-6-amine] (SQ 22,536), respectively. A neuronal NOS inhibitor (7-nitroindazole; 7-NI) also enhanced the response to NANC in vessels from wild-type, eNOS KO but not iNOS KO mice. Finally, PNS enhanced the release of immunoreactive CGRP from the perfused arterial mesenteric bed. CONCLUSIONS AND IMPLICATIONS Our study demonstrates a role for CGRP in the NANC-dependent reduction in perfusion pressure of the arterial but not venous mesenteric bed of the mouse.
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Affiliation(s)
- E Legros
- Department of Pharmacology, Medical School, Institut de pharmacologie de Sherbrooke, Université de Sherbrooke Sherbrooke, Québec, Canada
| | - C R Tirapelli
- Department of Psychiatry Nursing and Human Sciences, College of Nursing of Ribeirao Preto, University of Sao Paulo (USP) Ribeirao Preto, Brazil
| | - E Carrier
- Department of Pharmacology, Medical School, Institut de pharmacologie de Sherbrooke, Université de Sherbrooke Sherbrooke, Québec, Canada
| | - I Brochu
- Department of Pharmacology, Medical School, Institut de pharmacologie de Sherbrooke, Université de Sherbrooke Sherbrooke, Québec, Canada
| | - A Fournier
- INRS-Institut Armand-Frappier, Institut national de la recherche scientifique, Université du Québec, Laboratoire d'études moléculaires et, pharmacologiques des peptides Pointe-Claire (Montréal), Québec, Canada
| | - P D'Orléans-Juste
- Department of Pharmacology, Medical School, Institut de pharmacologie de Sherbrooke, Université de Sherbrooke Sherbrooke, Québec, Canada
- Author for correspondence:
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Hoi PM, Visintin C, Okuyama M, Gardiner SM, Kaup SS, Bennett T, Baker D, Selwood DL, Hiley CR. Vascular pharmacology of a novel cannabinoid-like compound, 3-(5-dimethylcarbamoyl-pent-1-enyl)-N-(2-hydroxy-1-methyl-ethyl)benzamide (VSN16) in the rat. Br J Pharmacol 2007; 152:751-64. [PMID: 17891160 PMCID: PMC2190032 DOI: 10.1038/sj.bjp.0707470] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND AND PURPOSE A putative novel cannabinoid receptor mediates vasorelaxation to anandamide and abnormal-cannabidiol and is blocked by O-1918 and by high concentrations of rimonabant. This study investigates VSN16, a novel water-soluble agonist, as a vasorelaxant potentially acting at non-CB1, non-CB2 cannabinoid receptors in the vasculature. EXPERIMENTAL APPROACH VSN16 and some analogues were synthesized and assayed for vasodilator activity in the rat third generation mesenteric artery using wire myography. Also carried out with VSN16 were haemodynamic studies in conscious rats and binding studies to CB1 receptors of rat cerebellum. KEY RESULTS VSN16 relaxed mesenteric arteries in an endothelium-dependent manner. The vasorelaxation was antagonized by high concentrations of the classical cannabinoid antagonists, rimonabant and AM 251, as well as by O-1918, an antagonist at the abnormal-cannabidiol receptor but not at CB1 or CB2 receptors. It did not affect [3H]CP55,940 binding to CB1 receptors in rat cerebellum. The vasorelaxation was not pertussis toxin-sensitive but was reduced by inhibition of nitric oxide synthesis, Ca(2+)-sensitive K+ channels (KCa) and TRPV1 receptors. In conscious rats VSN16 transiently increased blood pressure and caused a longer-lasting increase in mesenteric vascular conductance. Structure-activity studies on vasorelaxation showed a stringent interaction with the target receptor. CONCLUSIONS AND IMPLICATIONS VSN16 is an agonist at a novel cannabinoid receptor of the vasculature. It acts on the endothelium to release nitric oxide and activate KCa and TRPV1. As it is water-soluble it might be useful in bringing about peripheral cannabinoid-like effects without accompanying central or severe cardiovascular responses.
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Affiliation(s)
- P M Hoi
- Department of Pharmacology, University of Cambridge Cambridge, UK
| | - C Visintin
- The Wolfson Institute for Biomedical Research, University College London London, UK
| | - M Okuyama
- The Wolfson Institute for Biomedical Research, University College London London, UK
| | - S M Gardiner
- School of Biomedical Sciences, Queen's Medical Centre, University of NottinghamUK
| | - S S Kaup
- Department of Pharmacology, University of Cambridge Cambridge, UK
| | - T Bennett
- School of Biomedical Sciences, Queen's Medical Centre, University of NottinghamUK
| | - D Baker
- Institute of Cell and Molecular Science, Barts and The London, Queen Mary's School of Medicine and Dentistry London, UK
| | - D L Selwood
- The Wolfson Institute for Biomedical Research, University College London London, UK
| | - C R Hiley
- Department of Pharmacology, University of Cambridge Cambridge, UK
- Author for correspondence:
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Herradón E, Martín MI, López-Miranda V. Characterization of the vasorelaxant mechanisms of the endocannabinoid anandamide in rat aorta. Br J Pharmacol 2007; 152:699-708. [PMID: 17704831 PMCID: PMC2190007 DOI: 10.1038/sj.bjp.0707404] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND AND PURPOSE Studies in isolated preparations of vascular tissue (mainly resistance vessels) provide evidence that anandamide exerts vasorelaxation. The aim of the present work was to further characterize the mechanisms involved in the vascular response induced by anandamide in a conduit vessel, rat aorta. EXPERIMENTAL APPROACH Isometric tension changes in response to a cumulative concentration-response curve of anandamide (1 nM-100 micro M) were recorded in aortic rings from male Wistar rats. The involvement of a number of factors in this relaxation was investigated including endothelium-derived vasorelaxant products, cannabinoid and vanilloid receptors (transient potential vanilloid receptor-1 (TRPV1)), release of calcitonin gene-related peptide (CGRP), anandamide metabolism and the membrane transporter for anandamide. KEY RESULTS Anandamide caused a significant concentration-dependent vasorelaxation in rat aorta. This vasorelaxation was significantly inhibited by Pertussis toxin, by a non-CB1/non-CB2 cannabinoid receptor antagonist, by endothelial denudation, by inhibition of nitric oxide synthesis or inhibition of prostanoid synthesis via cyclooxygenase-2 (COX-2), by blockade of prostaglandin receptors EP4 and by a fatty acid amino hydrolase inhibitor. Antagonists for CB1, CB2, TRPV1 or CGRP receptors, an inhibitor of the release of endothelium-derived hyperpolarizing factor, and an inhibitor of anandamide transport did not modify the vascular response to anandamide. CONCLUSIONS AND IMPLICATIONS Our results demonstrate, for the first time, the involvement of the non-CB1/non-CB2 cannabinoid receptor and an anandamide-arachidonic acid-COX-2 derived metabolite (which acts on EP4 receptors) in the endothelial vasorelaxation caused by anandamide in rat aorta.
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MESH Headings
- Animals
- Aorta, Abdominal/drug effects
- Aorta, Abdominal/physiology
- Apamin/pharmacology
- Arachidonic Acids/pharmacology
- Benzamides/pharmacology
- Calcitonin Gene-Related Peptide/pharmacology
- Camphanes/pharmacology
- Cannabinoid Receptor Modulators/pharmacology
- Capsaicin/analogs & derivatives
- Capsaicin/pharmacology
- Carbamates/pharmacology
- Charybdotoxin/pharmacology
- Dose-Response Relationship, Drug
- Endocannabinoids
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/physiology
- In Vitro Techniques
- Indomethacin/pharmacology
- Isoindoles/pharmacology
- Male
- NG-Nitroarginine Methyl Ester/pharmacology
- Nitric Oxide/antagonists & inhibitors
- Nitric Oxide/biosynthesis
- Peptide Fragments/pharmacology
- Piperidines/pharmacology
- Polyunsaturated Alkamides/pharmacology
- Pyrazoles/administration & dosage
- Pyrazoles/pharmacology
- Rats
- Rats, Wistar
- Receptor, Cannabinoid, CB1/antagonists & inhibitors
- Receptor, Cannabinoid, CB2/antagonists & inhibitors
- Rimonabant
- Sulfonamides/pharmacology
- Vasodilation/drug effects
- Vasodilation/physiology
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Affiliation(s)
- E Herradón
- Área de Farmacología, Dpto. Ciencias de la Salud III, Facultad Ciencias de la Salud, Universidad Rey Juan Carlos, Alcorcón Madrid, Spain
| | - M I Martín
- Área de Farmacología, Dpto. Ciencias de la Salud III, Facultad Ciencias de la Salud, Universidad Rey Juan Carlos, Alcorcón Madrid, Spain
| | - V López-Miranda
- Área de Farmacología, Dpto. Ciencias de la Salud III, Facultad Ciencias de la Salud, Universidad Rey Juan Carlos, Alcorcón Madrid, Spain
- Author for correspondence:
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Akabori H, Yamamoto H, Tsuchihashi H, Mori T, Fujino K, Shimizu T, Endo Y, Tani T. Transient receptor potential vanilloid 1 antagonist, capsazepine, improves survival in a rat hemorrhagic shock model. Ann Surg 2007; 245:964-70. [PMID: 17522523 PMCID: PMC1876964 DOI: 10.1097/01.sla.0000255577.80800.e1] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
OBJECTIVE To evaluate the role of transient receptor potential vanilloid 1 (TRPV1) in a rat hemorrhagic shock (HS) model using the TRPV1 antagonist, capsazepine (CPZ). SUMMARY BACKGROUND DATA TRPV1, distributed within the sensory nerve, plays a role in the regulation of cardiovascular functions. TRPV1 may be involved in the cardiovascular responses to HS. METHODS Male rats were anesthetized and HS was induced with the mean arterial pressure (MAP) at 30 mm Hg for 90 minutes. CPZ (5.0 micromol/kg) was administered at 30 minutes after the shock induction, and the 24-hour survival rates were assessed. The MAP, heart rate, and shed blood volume (SBV) were recorded throughout the experiment. Arterial blood gas analysis and the plasma catecholamines levels were measured before and after HS. Double-immunohistochemistry for Fos and tyrosine hydroxylase (TH) was performed in the rostral ventrolateral medulla (RVLM) of the brain. RESULTS CPZ significantly improved the 24-hour survival rates, which was accompanied by the increase in the MAP and the SBV, a decrease of the plasma catecholamines levels, and attenuation of the severe metabolic acidosis. Furthermore, CPZ reduced the percentage of double-labeled neurons for Fos and TH in the RVLM of the rat brain. CONCLUSIONS TRPV1 may be involved in the regulation of the cardiovascular responses to HS, at least in part, by recruiting catecholaminergic neurons in the RVLM. CPZ appears to induce metabolic compensations, which may be potentially useful in HS.
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Affiliation(s)
- Hiroya Akabori
- Department of Surgery, Shiga University of Medical Science, Seta-Tsukinowa-cho, Otsu, Shiga, Japan 520-2192
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Pakdeechote P, Dunn WR, Ralevic V. Cannabinoids inhibit noradrenergic and purinergic sympathetic cotransmission in the rat isolated mesenteric arterial bed. Br J Pharmacol 2007; 152:725-33. [PMID: 17641668 PMCID: PMC2190027 DOI: 10.1038/sj.bjp.0707397] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND AND PURPOSE Noradrenaline and ATP are sympathetic co-transmitters. In the rat perfused mesenteric bed cannabinoids have been shown to modify the overall response to sympathetic nerve stimulation. This study has assessed whether cannabinoid receptor activation modulates differentially the noradrenergic and purinergic components of sympathetic vasoconstriction. EXPERIMENTAL APPROACH Rat mesenteric beds were perfused with physiological salt solution and the effects of cannabinoids on responses to nerve stimulation, or exogenous noradrenaline or alpha,beta-methylene ATP (alpha,beta-meATP; P2X receptor agonist) were determined after raising tone with U46619. The effects of cannabinoids on the noradrenaline and ATP components of sympathetic neurotransmission were assessed using the alpha 1-adrenoceptor antagonist, prazosin, or after P2X receptor desensitization with alpha,beta-meATP. KEY RESULTS Anandamide, WIN 55,212-2 and CP55,940 attenuated sympathetic neurogenic vasoconstrictor responses. The inhibitory actions of anandamide and WIN 55,212-2 were blocked by LY320135, a CB1 receptor antagonist, but not by SR144528, a CB2 receptor antagonist. The inhibitory actions of CP55,940 were unaffected by LY320135 and SR144528. WIN 55,212-3, the inactive S(-) enantiomer of WIN 55,212-2, had no effect on sympathetic neurogenic responses. None of the cannabinoids affected contractile responses to exogenous noradrenaline or alpha,beta-meATP. Anandamide and WIN 55,212-2 inhibited both the noradrenaline and ATP components of the sympathetic neurogenic contractile responses, with effects on the ATP component being most marked. CONCLUSIONS AND IMPLICATIONS These results indicate that prejunctional CB1-like receptors mediate the sympathoinhibitory action of anandamide and WIN 55,212-2, but not CP55,940, in the rat mesenteric bed. Cannabinoids inhibit both the noradrenergic and purinergic components of sympathetic neurotransmission.
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MESH Headings
- 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid/pharmacology
- Adenosine Triphosphate/analogs & derivatives
- Adenosine Triphosphate/pharmacology
- Adrenergic Fibers/drug effects
- Adrenergic Fibers/physiology
- Animals
- Arachidonic Acids/pharmacology
- Benzofurans/pharmacology
- Benzoxazines/pharmacology
- Camphanes/pharmacology
- Cannabinoids/pharmacology
- Cyclohexanols/pharmacology
- Dose-Response Relationship, Drug
- Electric Stimulation
- Endocannabinoids
- In Vitro Techniques
- Male
- Mesenteric Arteries/drug effects
- Mesenteric Arteries/innervation
- Mesenteric Arteries/physiology
- Morpholines/pharmacology
- Muscle Tonus/drug effects
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/innervation
- Muscle, Smooth, Vascular/physiology
- Naphthalenes/pharmacology
- Norepinephrine/pharmacology
- Perfusion
- Polyunsaturated Alkamides/pharmacology
- Prazosin/pharmacology
- Pyrazoles/pharmacology
- Rats
- Rats, Wistar
- Receptor, Cannabinoid, CB1/antagonists & inhibitors
- Receptor, Cannabinoid, CB2/antagonists & inhibitors
- Receptors, Purinergic P2/physiology
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Affiliation(s)
- P Pakdeechote
- Centre for Integrated Systems Biology & Medicine, School of Biomedical Sciences, University of Nottingham Nottingham, UK
| | - W R Dunn
- Centre for Integrated Systems Biology & Medicine, School of Biomedical Sciences, University of Nottingham Nottingham, UK
| | - V Ralevic
- Centre for Integrated Systems Biology & Medicine, School of Biomedical Sciences, University of Nottingham Nottingham, UK
- Author for correspondence:
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27
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Ghasemi M, Sadeghipour H, Shafaroodi H, Nezami BG, Gholipour T, Hajrasouliha AR, Tavakoli S, Nobakht M, Moore KP, Mani AR, Dehpour AR. Role of the nitric oxide pathway and the endocannabinoid system in neurogenic relaxation of corpus cavernosum from biliary cirrhotic rats. Br J Pharmacol 2007; 151:591-601. [PMID: 17486141 PMCID: PMC2013996 DOI: 10.1038/sj.bjp.0707279] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
BACKGROUND AND PURPOSE Relaxation of corpus cavernosum, which is mediated by nitric oxide (NO) released from non-adrenergic non-cholinergic (NANC) neurotransmission, is critical for inducing penile erection and can be affected by many pathophysiological conditions. However, the peripheral effect of liver cirrhosis on erectile function is as yet unknown. The aim of the present study was to investigate the effect of biliary cirrhosis on NANC-mediated relaxation of rat corpus cavernosum and the possible roles of endocannabinoid and nitric oxide systems in this model. EXPERIMENTAL APPROACH Cirrhosis was induced by bile duct ligation. Controls underwent sham operation. Four weeks later, strips of corpus cavernosum were mounted in a standard organ bath and NANC-mediated relaxations were obtained by applying electrical field stimulation. KEY RESULTS The NANC-mediated relaxation was enhanced in corporal strips from cirrhotic animals. Anandamide potentiated the relaxations in both groups. Either AM251 (CB(1) antagonist) or capsazepine (vanilloid VR(1) antagonist), but not AM630 (CB(2) antagonist), prevented the enhanced relaxations of cirrhotic strips. Either the non-selective NOS inhibitor L-NAME or the selective neuronal NOS inhibitor L-NPA inhibited relaxations in both groups, but cirrhotic groups were more resistant to the inhibitory effects of these agents. Relaxations to sodium nitroprusside (NO donor) were similar in tissues from the two groups. CONCLUSIONS AND IMPLICATIONS Cirrhosis potentiates the neurogenic relaxation of rat corpus cavernosum probably via the NO pathway and involving cannabinoid CB(1) and vanilloid VR(1) receptors.
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Affiliation(s)
- M Ghasemi
- Department of Pharmacology, School of Medicine, Medical Sciences/University of Tehran Tehran, Iran
- The UCL Institute of Hepatology, Department of Medicine, Royal Free and University College Medical School, UCL London, UK
| | - H Sadeghipour
- Department of Pharmacology, School of Medicine, Medical Sciences/University of Tehran Tehran, Iran
| | - H Shafaroodi
- Department of Pharmacology, Tehran Medical Unit, Islamic Azad University of Medical Sciences Tehran, Iran
| | - B G Nezami
- Department of Pharmacology, School of Medicine, Medical Sciences/University of Tehran Tehran, Iran
| | - T Gholipour
- Department of Pharmacology, School of Medicine, Medical Sciences/University of Tehran Tehran, Iran
| | - A R Hajrasouliha
- Department of Pharmacology, School of Medicine, Medical Sciences/University of Tehran Tehran, Iran
| | - S Tavakoli
- Department of Pharmacology, School of Medicine, Medical Sciences/University of Tehran Tehran, Iran
| | - M Nobakht
- Department of Histology, Medical School, Iran University of Medical Sciences Tehran, Iran
| | - K P Moore
- The UCL Institute of Hepatology, Department of Medicine, Royal Free and University College Medical School, UCL London, UK
| | - A R Mani
- The UCL Institute of Hepatology, Department of Medicine, Royal Free and University College Medical School, UCL London, UK
| | - A R Dehpour
- Department of Pharmacology, School of Medicine, Medical Sciences/University of Tehran Tehran, Iran
- Author for correspondence:
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Starowicz K, Nigam S, Di Marzo V. Biochemistry and pharmacology of endovanilloids. Pharmacol Ther 2007; 114:13-33. [PMID: 17349697 DOI: 10.1016/j.pharmthera.2007.01.005] [Citation(s) in RCA: 275] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2007] [Accepted: 01/24/2007] [Indexed: 11/28/2022]
Abstract
Endovanilloids are defined as endogenous ligands and activators of transient receptor potential (TRP) vanilloid type 1 (TRPV1) channels. The first endovanilloid to be identified was anandamide (AEA), previously discovered as an endogenous agonist of cannabinoid receptors. In fact, there are several similarities, in terms of opposing actions on the same intracellular signals, role in the same pathological conditions, and shared ligands and tissue distribution, between TRPV1 and cannabinoid CB(1) receptors. After AEA and some of its congeners (the unsaturated long chain N-acylethanolamines), at least 2 other families of endogenous lipids have been suggested to act as endovanilloids: (i) unsaturated long chain N-acyldopamines and (ii) some lipoxygenase (LOX) metabolites of arachidonic acid (AA). Here we discuss the mechanisms for the regulation of the levels of the proposed endovanilloids, as well as their TRPV1-mediated pharmacological actions in vitro and in vivo. Furthermore, we outline the possible pathological conditions in which endovanilloids, acting at sometimes aberrantly expressed TRPV1 receptors, might play a role.
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Affiliation(s)
- Katarzyna Starowicz
- Institute of Biomolecular Chemistry, Endocannabinoid Research Group, C.N.R., Pozzuoli, Naples, Italy
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29
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Ho WSV, Randall MD. Endothelium-dependent metabolism by endocannabinoid hydrolases and cyclooxygenases limits vasorelaxation to anandamide and 2-arachidonoylglycerol. Br J Pharmacol 2007; 150:641-51. [PMID: 17245358 PMCID: PMC1942073 DOI: 10.1038/sj.bjp.0707141] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND AND PURPOSE The endocannabinoids, N-arachidonoylethanolamide (anandamide) and 2-arachidonoylglycerol (2-AG) are rapidly degraded by fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MGL). Whilst these lipid mediators are known to modulate vascular tone, the extent to which they are inactivated via local metabolism in the vasculature remains unclear. EXPERIMENTAL APPROACH In rat isolated small mesenteric arteries, the regulatory role of FAAH, MGL and cyclooxygenase (COX) in relaxant responses to anandamide and 2-AG was evaluated by using inhibitors of these enzymes. Relaxations to non-hydrolysable analogues of endocannabinoids and arachidonic acid were also examined. KEY RESULTS Relaxation to anandamide but not 2-AG was potentiated by the selective FAAH inhibitor, URB597 (1 microM). In contrast, MAFP (10 microM; an inhibitor of FAAH and MGL) enhanced responses to both anandamide and 2-AG. Inhibition of COX-1 by indomethacin (10 microM) potentiated relaxations to 2-AG, whereas inhibition of COX-2 by nimesulide (10 microM) potentiated anandamide-induced relaxation. With the exception of MAFP, effects of FAAH and COX inhibitors were dependent on the endothelium. Relaxation to methanandamide and noladin ether, the non-hydrolysable analogues of anandamide and 2-AG respectively, were insensitive to the enzyme inhibitors. CONCLUSION AND IMPLICATIONS This study shows that local activity of FAAH, MGL and COX, which is present largely in the endothelium, limits the vasodilator action of endocannabinoids in rat small mesenteric arteries. Despite the differential roles played by these enzymes on relaxation to anandamide versus 2-AG, our results suggest that inhibitors of these enzymes enhance the vascular impact of endocannabinoids.
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Affiliation(s)
- W-S V Ho
- School of Biomedical Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, UK.
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30
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Dannert MT, Alsasua A, Herradon E, Martín MI, López-Miranda V. Vasorelaxant effect of Win 55,212-2 in rat aorta: New mechanisms involved. Vascul Pharmacol 2007; 46:16-23. [PMID: 16860612 DOI: 10.1016/j.vph.2006.06.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2006] [Revised: 05/22/2006] [Accepted: 06/09/2006] [Indexed: 10/24/2022]
Abstract
R(+)-[2,3-dihydro-5-methyl-3-[(moroholinyl)methyl] pyrrolo [1,2,3-de]-1,4benzoxazinyl]-1(1-naphthalenyl) methanone mesylate (Win 55,212-2) is a synthetic cannabinoid classically classified as a potent CB(1) and CB(2) agonist with high stereoselectivity and a slight preference for CB(2) cannabinoid receptors. Its vascular actions are not always explained by its binding to these cannabinoid receptors and new targets are being proposed. The aim of this study was to further assess the vascular actions of Win 55,212-2. Isometric tension changes in response to a cumulative concentration-response curve of Win 55,212-2 (10(-9) M-10(-4) M) were recorded in aortic rings from male Wistar rats. The involvement of the endothelium, cannabinoid receptors, vanilloid receptors, and the release of calcitonin gene related peptide (CGRP) was tested. Win 55,212-2 caused a concentration-dependent vasorelaxation in rat aorta. This vascular effect was significantly inhibited by endothelial denudation, inhibition of nitric oxide synthesis, a CB(1) receptor antagonist, a transient receptor potential vanilloid-1 antagonist, capsaicin desensibilization, and a CGRP receptor antagonist (P<0.001). CB(2) and non-CB(1)/non-CB(2) receptor antagonists only caused a slight inhibitory effect in vasorelaxation to Win 55,212-2. The present findings indicate that endothelium and nitric oxide-dependent vasorelaxation induced by Win 55,212-2 mainly involves vanilloid receptors while CB(1), CB(2) and nonCB(1)/nonCB(2) cannabinoid receptors have a minor participation in its vascular effect.
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Affiliation(s)
- M T Dannert
- Universidad Complutense de Madrid, Facultad de Medicina, Dpto Farmacología, Avda Complutense s/n 28040 Madrid, Spain
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31
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Ghasemi M, Sadeghipour H, Mani AR, Tavakoli S, Hajrasouliha AR, Ebrahimi F, Dehpour AR. Effect of anandamide on nonadrenergic noncholinergic-mediated relaxation of rat corpus cavernosum. Eur J Pharmacol 2006; 544:138-45. [PMID: 16824514 DOI: 10.1016/j.ejphar.2006.06.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2005] [Revised: 05/27/2006] [Accepted: 06/02/2006] [Indexed: 12/17/2022]
Abstract
The purpose of this study was to investigate the effect of the endogenous cannabinoid anandamide on the nonadrenergic noncholinergic (NANC) relaxant responses to electrical field stimulation in isolated rat corpus cavernosum. The corporal strips were mounted under tension in a standard oxygenated organ bath with guanethidine sulfate (5 microM) and atropine (1 microM) (to produce adrenergic and cholinergic blockade). The strips were precontracted with phenylephrine hydrochloride (7.5 microM) and electrical field stimulation was applied at different frequencies to obtain NANC-mediated relaxation. The expression of CB1, CB2 and vanilloid receptor proteins within the rat corpus cavernosum was evaluated using western blot analysis. The results showed that the relaxant responses to electrical stimulation were significantly enhanced in the presence of anandamide at 1 and 3 microM. The potentiating effect of anandamide (1 microM) on relaxation responses was significantly attenuated by either the selective cannabinoid CB1 receptor antagonist N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2, 4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide (AM251; 1 microM) or the vanilloid receptor antagonist capsazepine (3 microM), but not by the selective cannabinoid CB2 receptor antagonist 6-iodo-2-methyl-1-[2-(4-morpholinyl) ethyl]-1H-indol-3-yl (4-methoxyphenyl)methanone (AM630; 1 microM). Neither of these antagonists had influence on relaxation responses. Indomethacin (20 microM) had no effect on NANC-mediated relaxation in the presence or absence of anandamide (1 microM). Preincubation with Nw-Nitro-L-Arginine Methyl Ester (L-NAME; 1 microM) significantly inhibited the relaxation responses in the presence or absence of 1 microM anandamide. Although at 30 nM, L-NAME did not cause a significant inhibition of relaxant responses individually, it significantly inhibited the potentiating effect of anandamide (1 microM) on relaxation responses. Anandamide (1 microM) had no influence on concentration-dependent relaxant responses to sodium nitroprusside (10 nM-1 mM), a nitric oxide (NO) donor. The western blotting of corporal tissues demonstrated the existence of both vanilloid and CB1 receptors in corporal strips. In conclusion, our results showed that anandamide has a potentiating effect on NANC-mediated relaxation of rat corpus cavernosum through both CB1 and vanilloid receptors and the NO-mediated component of the NANC relaxant responses to electrical stimulation is involved in this enhancement.
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Affiliation(s)
- Mehdi Ghasemi
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, P.O. Box: 13145-784, Tehran, Iran
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32
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Hoi PM, Hiley CR. Vasorelaxant effects of oleamide in rat small mesenteric artery indicate action at a novel cannabinoid receptor. Br J Pharmacol 2006; 147:560-8. [PMID: 16415907 PMCID: PMC1616976 DOI: 10.1038/sj.bjp.0706643] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Oleamide (cis-9-octadecenoamide) exhibits some cannabimimetic responses despite its low affinities at the currently known cannabinoid receptors. Here we have investigated whether or not it is a vasorelaxant in rat small mesenteric arteries. Oleamide elicited vasorelaxation (EC50=1.2+/-0.2 microM, Rmax=99.1+/-3.9%, n=8) which was reduced by endothelial removal. Nitric oxide synthase inhibition reduced the response (EC50=5.3+/-1.6 microM, Rmax=59.2+/-7.7%, n=7; P<0.01) as did blockade of Ca2+-sensitive K+ channels (KCa) with apamin plus charybdotoxin (both 50 nM) (EC50=2.1+/-0.2 microM, Rmax=58.4+/-1.9%, n=5; P<0.05). Desensitisation of vanilloid receptors with capsaicin (10 microM for 30 min) shifted the oleamide concentration-response curve approximately 30-fold to the right (n=7; P<0.01). Pertussis toxin (400 ng ml-1 for 2 h) caused a two-fold shift in the response curve (EC50=2.2+/-0.4 microM, Rmax=66.8+/-4.5%, n=6; P<0.01). Rimonabant (CB1 cannabinoid receptor antagonist; SR141716A; 3 microM) significantly inhibited relaxation induced by oleamide (EC50=3.5+/-0.3 microM, Rmax=75.1+/-1.9%; n=8; P<0.05). In contrast, neither the more selective CB1 receptor antagonist, AM251 (1 microM), nor the CB2 antagonist, SR144528 (1 microM), had significant effects. O-1918 (10 microM), a putative antagonist at a novel endothelial cannabinoid receptor (abnormal-cannabidiol site), markedly reduced the relaxation to oleamide (n=7; P<0.01). It is concluded that oleamide responses in the rat isolated small mesenteric artery are partly dependent on the presence of the endothelium, activation of Ca2+-sensitive K+ channels (KC)) and involve capsaicin-sensitive sensory nerves. Oleamide may share a receptor (sensitive to rimonabant and O-1918, and coupled to KC) and Gi/o) with anandamide in this vessel. This might be distinct from both of the known cannabinoid receptors and the novel abnormal-cannabidiol site.
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Affiliation(s)
- Pui Man Hoi
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD
| | - C Robin Hiley
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge CB2 1PD
- Author for correspondence:
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Di Marzo V. A brief history of cannabinoid and endocannabinoid pharmacology as inspired by the work of British scientists. Trends Pharmacol Sci 2006; 27:134-40. [PMID: 16476494 DOI: 10.1016/j.tips.2006.01.010] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2005] [Revised: 10/19/2005] [Accepted: 01/26/2006] [Indexed: 11/25/2022]
Abstract
British scientists have played a leading role in the long history of cannabinoid and endocannabinoid research. Such research has progressed from the first crucial evaluation of the medicinal properties of Cannabis sativa in the Western world to pioneering studies of the chemical constituents of this plant, the development of in vitro biological assays to study cannabinoids, the identification of the mechanism of action of cannabinoids, the discovery of endocannabinoids and the assessment of their therapeutic implications. Stemming from the many innovative ideas and achievements of these researchers, I provide a personal view of where these studies have led us thus far and where they are likely to take us in the future.
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Affiliation(s)
- Vincenzo Di Marzo
- Endocannabinoid Research Group, Institute of Biomolecular Chemistry, Consiglio Nazionale delle Ricerche, Via Campi Flegrei 34, Comprensorio Olivetti, Fabbr. 70, 80078 Pozzuoli (NA) Italy.
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Movahed P, Evilevitch V, Andersson TLG, Jönsson BAG, Wollmer P, Zygmunt PM, Högestätt ED. Vascular effects of anandamide and N-acylvanillylamines in the human forearm and skin microcirculation. Br J Pharmacol 2005; 146:171-9. [PMID: 15997233 PMCID: PMC1576264 DOI: 10.1038/sj.bjp.0706313] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The endocannabinoid anandamide is an emerging potential signalling molecule in the cardiovascular system. Anandamide causes vasodilatation, bradycardia and hypotension in animals and has been implicated in the pathophysiology of endotoxic, haemorrhagic and cardiogenic shock, but its vascular effects have not been studied in man. Human forearm blood flow and skin microcirculatory flow were recorded using venous occlusion plethysmography and laser-Doppler perfusion imaging (LDPI), respectively. Each test drug was infused into the brachial artery or applied topically on the skin followed by a standardized pin-prick to disrupt the epidermal barrier. Anandamide failed to affect forearm blood flow when administered intra-arterially at infusion rates of 0.3-300 nmol min(-1). The highest infusion rate led to an anandamide concentration of approximately 1 microM in venous blood as measured by mass spectrometry. Dermal application of anandamide significantly increased skin microcirculatory flow and coapplication of the transient receptor potential vanilloid 1 (TRPV1) antagonist capsazepine inhibited this effect. The TRPV1 agonists capsaicin, olvanil and arvanil all induced concentration-dependent increases in skin blood flow and burning pain when administered dermally. Coapplication of capsazepine inhibited blood flow and pain responses to all three TRPV1 agonists. This study shows that locally applied anandamide is a vasodilator in the human skin microcirculation. The results are consistent with this lipid being an activator of TRPV1 on primary sensory nerves, but do not support a role for anandamide as a circulating vasoactive hormone in the human forearm vascular bed.
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Affiliation(s)
- Pouya Movahed
- Department of Clinical and Experimental Pharmacology, Lund University Hospital, SE-221 85 Lund, Sweden
| | - Vladimir Evilevitch
- Department of Clinical Physiology, Malmö University Hospital, SE-205 02 Malmö, Sweden
| | - Tomas L G Andersson
- Department of Clinical and Experimental Pharmacology, Lund University Hospital, SE-221 85 Lund, Sweden
| | - Bo A G Jönsson
- Department of Occupational and Environmental Medicine, Lund University Hospital, SE-221 85 Lund, Sweden
| | - Per Wollmer
- Department of Clinical Physiology, Malmö University Hospital, SE-205 02 Malmö, Sweden
| | - Peter M Zygmunt
- Department of Clinical and Experimental Pharmacology, Lund University Hospital, SE-221 85 Lund, Sweden
- Author for correspondence:
| | - Edward D Högestätt
- Department of Clinical and Experimental Pharmacology, Lund University Hospital, SE-221 85 Lund, Sweden
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Zhu Y, Wang Y, Wang DH. Diuresis and Natriuresis Caused by Activation of VR1-Positive Sensory Nerves in Renal Pelvis of Rats. Hypertension 2005; 46:992-7. [PMID: 16087784 DOI: 10.1161/01.hyp.0000174603.27383.67] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
To test the hypothesis that activation of the vanilloid receptor 1 (VR1) expressed in sensory nerves innervating the renal pelvis leads to diuresis and natriuresis, a selective VR1 receptor agonist, capsaicin (2.4 nmol), or vehicle was perfused intravenously or into the left renal pelvis of anesthetized rats at a rate without changing renal perfusion pressure. Mean arterial pressure was not altered by capsaicin administered intravenously or into the renal pelvis. Capsaicin perfusion into the left renal pelvis but not intravenously caused significant increases in urine flow rate and urinary sodium excretion bilaterally in a dose-dependent manner, which were abolished by capsazepine, a selective VR1 receptor antagonist, given ipsilaterally to the renal pelvis or by ipsilateral renal denervation. Capsaicin given intravenously or into the left renal pelvis increased plasma calcitonin gene-related peptide levels to the same extent. Increased plasma calcitonin gene-related peptide levels induced by capsaicin (68.9±2.8 pg/mL) perfusion into the renal pelvis was prevented either by capsazepine (22.5±10.1 pg/mL) given ipsilaterally into the renal pelvis or by ipsilateral renal denervation (25.9±2.3 pg/mL). Taken together, our data show that unilateral activation of VR1-positive sensory nerves innervating the renal pelvis leads to bilateral diuresis and natriuresis via a mechanism that is independent of plasma calcitonin gene-related peptide levels. These data suggest that VR1-positive sensory nerves in the kidney enhance renal excretory function, a mechanism that may be critically involved in sodium and fluid homeostasis.
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Affiliation(s)
- Yi Zhu
- Department of Medicine, College of Human Medicine, Michigan State University, East Lansing, MI 48824, USA
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36
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Wagner JA, Abesser M, Karcher J, Laser M, Kunos G. Coronary Vasodilator Effects of Endogenous Cannabinoids in Vasopressin-Preconstricted Unpaced Rat Isolated Hearts. J Cardiovasc Pharmacol 2005; 46:348-55. [PMID: 16116341 DOI: 10.1097/01.fjc.0000175437.87283.f2] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The mechanisms by which cannabinoids alter coronary vascular tone and cardiac performance are controversial. We investigated the effects of various cannabinoids in spontaneously beating Langendorff-perfused rat hearts. Bolus injections of anandamide (0.1-1 micromol) caused no change in coronary flow (CF) or left ventricular systolic pressure (LVSP). In hearts preperfused with vasopressin to induce vasoconstrictor tone, anandamide or the selective CB1 receptor agonist ACEA (1-100 nmol) dose-dependently increased CF by up to 267% and LVSP by 20 mm Hg. The metabolically stable endocannabinoid derivatives, R-methanandamide and noladin ether, displayed similar effects. In contrast, Delta-THC (10-100 nmol), the major psychoactive ingredient of cannabis, strongly decreased CF and LVSP. The CB2 receptor agonist JWH-133 (10-100 nmol) elicited vasodilator and positive inotropic effects only at higher doses. The CB1 antagonists SR141716A and AM-251 as well as the potassium channel inhibitors tetraethylammonium and iberiotoxin blocked the anandamide-induced increases in CF and LVSP, whereas the CB2 antagonist SR144528 and the putative "CB3 antagonist" O-1918 did not have an inhibitory effect. Immunohistochemistry revealed the presence of cardiac CB1 but no CB2 receptors. Anandamide and 2-arachidonoylglycerol were detected in heart tissue. However, combined application of fatty acid amidohydrolase inhibitors and the transport inhibitor AM-404 to augment tissue levels of endocannabinoids was without effect on CF or LVSP. We conclude that in the rat isolated heart with reestablished vasoconstrictor tone, cannabinoids including anandamide elicit coronary vasodilation and a secondary increase in contractility via CB1 receptors and potassium channels.
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Affiliation(s)
- Jens A Wagner
- Department of Internal Medicine I, Center of Cardiovascular Medicine, University of Würzburg, Würzburg, Germany.
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37
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Abstract
Cannabinoids and their synthetic and endogenous analogs affect a broad range of physiological functions, including cardiovascular variables, the most important component of their effect being profound hypotension. The mechanisms of the cardiovascular effects of cannabinoids in vivo are complex and may involve modulation of autonomic outflow in both the central and peripheral nervous systems as well as direct effects on the myocardium and vasculature. Although several lines of evidence indicate that the cardiovascular depressive effects of cannabinoids are mediated by peripherally localized CB1 receptors, recent studies provide strong support for the existence of as-yet-undefined endothelial and cardiac receptor(s) that mediate certain endocannabinoid-induced cardiovascular effects. The endogenous cannabinoid system has been recently implicated in the mechanism of hypotension associated with hemorrhagic, endotoxic, and cardiogenic shock, and advanced liver cirrhosis. Furthermore, cannabinoids have been considered as novel antihypertensive agents. A protective role of endocannabinoids in myocardial ischemia has also been documented. In this chapter, we summarize current information on the cardiovascular effects of cannabinoids and highlight the importance of these effects in a variety of pathophysiological conditions.
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Affiliation(s)
- P Pacher
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892-9413, USA.
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Randall MD, Kendall DA, O'Sullivan S. The complexities of the cardiovascular actions of cannabinoids. Br J Pharmacol 2004; 142:20-6. [PMID: 15131000 PMCID: PMC1574918 DOI: 10.1038/sj.bjp.0705725] [Citation(s) in RCA: 123] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The cardiovascular actions of cannbinoids are complex. In general they cause vasorelaxation in isolated blood vessels, while in anaesthetised animals they cause multiphasic responses which involve an early bradycardia and long-lasting hypotension. However, in conscious animals, the picture is one of bradycardia followed by pressor responses. Clearly, the responses to cannabinoids are dependent on the experimental conditions and synthetic cannabinoids and endocannabinoids exhibit different pharmacologies. In terms of mechanisms involved in the vascular responses to cannabinoids, the following have been implicated: the involvement of 'classical' cannabinoid receptors, the involvement of a novel endothelial cannabinoid receptor, the release of nitric oxide, the release of endothelium-derived hyperpolarising factor (EDHF), the activation of vanilloid receptors, metabolism of endocannabinoids to vasoactive molecules, and both peripheral inhibition and central excitation of the sympathetic nervous system.
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Affiliation(s)
- Michael D Randall
- School of Biomedical Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham NG7 2UH.
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López-Miranda V, Herradón E, Dannert MT, Alsasua A, Martín MI. Anandamide vehicles: a comparative study. Eur J Pharmacol 2004; 505:151-61. [PMID: 15556148 DOI: 10.1016/j.ejphar.2004.10.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2004] [Accepted: 10/04/2004] [Indexed: 10/26/2022]
Abstract
Among the studies that investigate the vasorelaxation induced by anandamide, one of the most frequent differences is the use of distinct solvents that could modify vascular function and explain the controversial results described. The aims of this study were: to evaluate the influence of different cannabinoid vehicles in vascular function of rat aorta, and to compare the vasorelaxation induced by anandamide dissolved in different vehicles. Vehicles were: ethanol (70%), Tween 80/ethanol (2:1 and 1:1), 1:1:18 (Tween 80/ethanol/saline) and dimethylsulphoxide (DMSO) 0.5%. All the vehicles tested, except DMSO 0.5%, modified the vascular and/or the endothelial function in rat aorta rings. Anandamide caused a time- and concentration-dependent vasorelaxation in all the experimental groups except in ethanol group, but the mechanisms involved in its vasorelaxation appear to be different depending on the vehicle used. The results obtained with vehicles containing Tween 80 suggest a non-endothelial component in the vasorelaxation caused by anandamide, while those obtained with DMSO at 0.5% suggest an endothelial component in this vasorelaxation.
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Affiliation(s)
- Visitación López-Miranda
- Universidad Rey Juan Carlos, Facultad Ciencias de la Salud, Dpto. Ciencias de la Salud, Unidad de Farmacología. Avda. Atenas s/n 28922 Alcorcón, Madrid, Spain.
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40
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Deng PY, Ye F, Cai WJ, Tan GS, Hu CP, Deng HW, Li YJ. Stimulation of calcitonin gene-related peptide synthesis and release. J Hypertens 2004; 22:1819-29. [PMID: 15311112 DOI: 10.1097/00004872-200409000-00028] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
BACKGROUND Previous investigations have demonstrated that capsaicin-sensitive primary sensory nerves play an important role in modulation of the peripheral resistance of the circulation system. The vanilloid receptor subtype 1 (VR1) is expressed almost exclusively in the primary sensory nerves and cell bodies of these sensory neurons. Rutaecarpine (Rut) can relax vascular smooth muscle via stimulation of calcitonin gene-related peptide (CGRP) release by activation of VR1. METHODS In the present study, we examined the depressor effect of Rut and the possible mechanisms in the phenol-induced hypertensive rats, in which hypertension was induced by injecting 50 microl of 10% phenol in the lower pole of the left kidney. RESULTS Acute administration of Rut (30, 100 or 300 microg/kg, i.v.) caused a depressor effect concomitantly with an increase in the plasma concentration of CGRP in a dose-dependent manner, which was blocked by capsaicin (used to deplete the CGRP from sensory nerves) or capsazepine (a competitive VR1 antagonist), causing an approximately 85% and approximately 80% change in mean arterial pressure, respectively, and by either of them, causing an approximately 90% elevation of plasma CGRP. In the chronic study, Rut at a dose of 3 or 6 mg/kg per day significantly lowered tail-cuff systolic blood pressure to 159 +/- 8 and 136 +/- 10 mmHg, respectively, compared with hypertensive rats (179 +/- 8 mmHg), and caused a sustained hypotensive effect from day 6 on. Pretreatment with capsaicin blocked the depressor effect of Rut by approximately 65%. Treatment with Rut significantly increased the synthesis and release of CGRP, as shown by the increase in the levels of CGRP mRNA and peptide in the dorsal root ganglia, the density of CGRP immunoreactive nerve fibers in the mesenteric artery, the CGRP content in the spinal cord and the plasma concentration of CGRP, which was markedly attenuated by pretreatment with capsaicin. CONCLUSION These results suggest, for the first time, that the hypotensive effect of Rut is mediated by stimulation of CGRP synthesis and release via activation of VR1 in the phenol-induced hypertensive rat.
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Affiliation(s)
- Pan-Yue Deng
- Department of Pharmacology, School of Pharmaceutical Sciences, Central South University, Changsha, Hunan, PR China
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Baker CL, McDougall JJ. The cannabinomimetic arachidonyl-2-chloroethylamide (ACEA) acts on capsaicin-sensitive TRPV1 receptors but not cannabinoid receptors in rat joints. Br J Pharmacol 2004; 142:1361-7. [PMID: 15277316 PMCID: PMC1575203 DOI: 10.1038/sj.bjp.0705902] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
The vasoactive effects of the synthetic cannabinoid (CB) arachidonyl-2-chloroethylamide (ACEA) was tested in the knee joints of urethane-anaesthetised rats. Experiments were also performed to determine whether these vasomotor responses could be blocked by the selective CB(1) receptor antagonists AM251 (N-(piperidin-1-yl)-5-(4-iodophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide) (10(-9) mol) and AM281 (1-(2,4-dichlorophenyl)-5-(4-iodophenyl)-4-methyl-N-4-morpholinyl-1H-pyrazole-3-carboxamide) (10(-8) mol), as well as the selective CB(2) receptor antagonist AM630 (6-iodo-2-methyl-1-[2-4(morpholinyl)ethyl]-[1H-indol-3-yl](4-methoxyphenyl)methanone) (10(-8) mol). Peripheral application of ACEA (10(-14)-10(-9) mol) onto the exposed surface of the knee joint capsule caused a dose-dependent increase in synovial blood flow. The dilator action of the CB occurred within 1 min after drug administration and rapidly returned to control levels shortly thereafter. The maximal vasodilator effect of ACEA corresponded to a 30% increase in articular perfusion compared to control levels. The hyperaemic action of ACEA was not significantly altered by coadministration of AM251, AM281 or AM630 (P>0.05; two-way ANOVA). The transient receptor potential channel vanilloid receptor 1 (TRPV(1)) antagonist capsazepine (10(-6) mol) significantly reduced the vasodilator effect of ACEA on joint blood vessels (P=0.002). Furthermore, destruction of unmyelinated and thinly myelinated joint sensory nerves by capsaicin (8-methyl-N-vanillyl-6-nonenamide) treatment also attenuated ACEA responses (P<0.0005). These data clearly demonstrate a vasodilator effect of the cannabinomimetic ACEA on knee joint perfusion. Rather than a classic CB receptor pathway, ACEA exerts its vasomotor influence by acting via TRPV(1) receptors located on the terminal branches of capsaicin-sensitive afferent nerves innervating the joint.
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Affiliation(s)
- Chris L Baker
- Department of Physiology and Biophysics, 3300, Hospital Drive NW, University of Calgary, Calgary, Alberta, Canada T2N 4N1
| | - Jason J McDougall
- Department of Physiology and Biophysics, 3300, Hospital Drive NW, University of Calgary, Calgary, Alberta, Canada T2N 4N1
- Author for correspondence:
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O'Sullivan SE, Kendall DA, Randall MD. Heterogeneity in the mechanisms of vasorelaxation to anandamide in resistance and conduit rat mesenteric arteries. Br J Pharmacol 2004; 142:435-42. [PMID: 15148250 PMCID: PMC1574972 DOI: 10.1038/sj.bjp.0705810] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
1 In order to address mechanistic differences between arterial vessel types, we have compared the vasorelaxant actions of anandamide in resistance (G3) and conduit (G0) mesenteric arteries. 2 Anandamide produced concentration-dependent relaxations of pre-constricted G3 arteries with a maximal response that was significantly greater than seen in G0. 3 The CB1 receptor selective antagonists SR141716A (100 nm) and AM251 (100 nm) caused reductions in the vasorelaxant responses to anandamide in both arteries. Maximal vasorelaxant responses to anandamide were reduced in both arteries after treatment with capsaicin to deplete sensory neurotransmitters (10 microm for 1 h). 4 Vasorelaxation to anandamide was not affected by the nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME, 300 microm) in either artery. Only responses in G3 arteries were sensitive to removal of the endothelium. In G3 vessels only, vasorelaxation to anandamide was reduced by inhibition of EDHF activity with a combination of charybdotoxin (100 nm) and apamin (500 nm) in the presence of L-NAME (300 microm) and indomethacin (10 microm). 5 Antagonism of the novel endothelial cannabinoid receptor (O-1918, 1 microm) caused a reduction in the sensitivity to anandamide in G3 but not G0. 6 G3, but not G0, vessels showed a small reduction in vasorelaxant responses to anandamide after inhibition of gap junctional communication with 18alpha-GA (100 microm). 7 These results demonstrate that there are differences in the mechanisms of vasorelaxation to anandamide between conduit and resistance mesenteric arteries. In small resistance vessels, vasorelaxation occurs through stimulation of vanilloid receptors, CB1 receptors, and an endothelial receptor coupled to EDHF release. By contrast, in the larger mesenteric artery, vasorelaxation is almost entirely due to stimulation of vanilloid receptors and CB1 receptors, and is endothelium-independent.
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Affiliation(s)
- Saoirse E O'Sullivan
- School of Biomedical Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH. saoirse.o'
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43
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Pacher P, Bátkai S, Kunos G. Haemodynamic profile and responsiveness to anandamide of TRPV1 receptor knock-out mice. J Physiol 2004; 558:647-57. [PMID: 15121805 PMCID: PMC1664980 DOI: 10.1113/jphysiol.2004.064824] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The endocannabinoid anandamide and cannabinoid (CB) receptors have been implicated in the hypotension in various forms of shock and in advanced liver cirrhosis. Anandamide also activates vanilloid TRPV(1) receptors on sensory nerve terminals, triggering the release of calcitonin gene-related peptide which elicits vasorelaxation in isolated blood vessels in vitro. However, the contribution of TRPV(1) receptors to the in vivo hypotensive effect of anandamide is equivocal. We compared the cardiac performance of anaesthetized TRPV(1) knockout (TRPV(1)(-/-)) mice and their wild-type (TRPV(1)(+/+)) littermates and analysed in detail the haemodynamic effects of anandamide using the Millar pressure-volume conductance catheter system. Baseline cardiovascular parameters and systolic and diastolic function at different preloads were similar in TRPV(1)(-/-) and TRPV(1)(+/+) mice. The predominant hypotensive response to bolus intravenous injections of anandamide and the associated decrease in cardiac contractility and total peripheral resistance (TPR) were similar in TRPV(1)(+/+) and TRPV(1)(-/-) mice, as was the ability of the CB(1) receptor antagonist SR141716 to completely block these effects. In TRPV(1)(+/+) mice, this hypotensive response was preceded by a transient, profound drop in cardiac contractility and heart rate and an increase in TPR, followed by a brief pressor response, effects which were unaffected by SR141716 and were absent in TRPV(1)(-/-) mice. These results indicate that mice lacking TRPV(1) receptors have a normal cardiovascular profile and their predominant cardiovascular depressor response to anandamide is mediated through CB(1) receptors. The role of TRPV(1) receptors is limited to the transient activation of the Bezold-Jarisch reflex by very high initial plasma concentrations of anandamide.
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Affiliation(s)
- Pál Pacher
- Laboratory of Physiologic Studies, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA.
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44
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O'Sullivan SE, Kendall DA, Randall MD. Characterisation of the vasorelaxant properties of the novel endocannabinoid N-arachidonoyl-dopamine (NADA). Br J Pharmacol 2004; 141:803-12. [PMID: 14769783 PMCID: PMC1574254 DOI: 10.1038/sj.bjp.0705643] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. We have investigated the vascular effects of N-arachidonoyl-dopamine (NADA), a novel endocannabinoid/vanilloid. NADA caused vasorelaxant effects comparable to those of anandamide in small mesenteric vessels (G3), the superior mesenteric artery (G0) and in the aorta. 2. In G3, addition of N(G)-nitro-l-arginine methyl ester (300 microm) or the dopamine (D(1)) receptor antagonist (SCH23390, 1 microm) did not affect responses to NADA. In the presence of 60 mm KCl, after de-endothelialisation, or after K(+) channel inhibition with charybdotoxin (100 nm) and apamin (500 nm), relaxant responses to NADA were inhibited. 3. In G3, pretreatment with the vanilloid receptor (VR) agonist capsaicin (10 microm) or the VR antagonist capsazepine (10 microm) reduced vasorelaxation to NADA. 4. In G3, application of the CB(1) antagonist SR141716A at 1 microm but not 100 nm reduced the potency of NADA. Another CB(1) antagonist, AM251 (100 nm and 1 microm), did not affect vasorelaxation to NADA. After endothelial denudation, SR141716A (1 microm) did not reduce the responses further. A combination of capsaicin and SR141716A (1 microm) reduced vasorelaxation to NADA further than with capsaicin pretreatment alone. The novel endothelial cannabinoid (CB) receptor antagonist O-1918 opposed vasorelaxation to NADA in G3. 5. In the superior mesenteric artery (G0), vasorelaxation to NADA was not dependent on an intact endothelium and was not sensitive to O-1918, but was sensitive to capsaicin and SR141716A or AM251 (both 100 nm). 6. The results of the present study demonstrate for the first time that NADA is a potent vasorelaxant. In G3, the effects of NADA are mediated by stimulation of the VR and the novel endothelial CB receptor, while in G0, vasorelaxation is mediated through VR(1) and CB(1) receptors.
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Affiliation(s)
- Saoirse E O'Sullivan
- School of Biomedical Sciences, University of Nottingham, Queen's Medical Centre, Nottingham NG7 2UH. saoirse.o'
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Abstract
OBJECTIVE To test the hypothesis that activation of the vanilloid receptor (VR1) by high salt intake prevents salt-induced increases in arterial pressure via stimulation of release of calcitonin gene-related peptide (CGRP) from sensory nerves. DESIGN AND METHODS Two protocols were used: (1) Wistar rats fed a normal sodium (NS) diet (0.5%) were given intravenous injection of vehicle, capsaicin (CAP), or capsazepine (CAPZ) (a selective VR1 antagonist) plus CAP; and (2) rats were pair-fed a high salt (HS) diet (4%) or NS diet for 3 days and used either for arterial cannulation for measurement of mean arterial pressure (MAP) or for collection of plasma and tissues. Radioimmunoassay, western blot, and fluorescent immunohistochemistry were used, respectively, to determine the plasma CGRP level, VR1 protein content, and co-localization of VR1 and CGRP. RESULTS CAP increased plasma CGRP levels and decreased MAP in rats fed a NS diet. CAPZ blocked CAP-induced increases in plasma CGRP levels and CAP-induced decreases in MAP. HS intake increased plasma CGRP levels by approximately 60% without changing the baseline MAP, but MAP was increased by CAPZ in HS-treated rats when compared with NS-treated rats. VR1 protein expression, which co-localized with CGRP, was increased in mesenteric resistance arteries and the renal medulla. CONCLUSION HS intake activates VR1, which plays a counter-regulatory role in preventing salt-induced increases in arterial pressure via stimulation of release of CGRP from sensory nerves. Increased VR1 expression in vascular and renal tissues may serve as a compensatory response to HS intake, which contributes to maintenance of normal salt sensitivity.
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Affiliation(s)
- Jianping Li
- Department of Medicine and Neuroscience Program, Michigan State University, East Lansing, MI 48824, USA
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46
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Abstract
Cannabinoids are cell membrane-derived signalling molecules that are released from nerves, blood cells and endothelial cells, and have diverse biological effects. They act at two distinct types of G-protein-coupled receptors, cannabinoid CB(1) and CB(2) receptors. Cannabinoid CB(1) receptors are highly localised in the central nervous system and are also found in some peripheral tissues, and cannabinoid CB(2) receptors are found outside the central nervous system, in particular in association with immune tissues. Novel actions of cannabinoids at non-CB(1) non-CB(2) cannabinoid-like receptors and vanilloid VR1 receptors have also recently been described. There is growing evidence that, among other roles, cannabinoids can act at prejunctional sites to modulate peripheral autonomic and sensory neurotransmission, and the present article is aimed at providing an overview of this. Inhibitory cannabinoid CB(1) receptors are expressed on the peripheral terminals of autonomic and sensory nerves. The role of cannabinoid receptor ligands in modulation of sensory neurotransmission is complex, as certain of these (anandamide, an "endocannabinoid", and N-arachidonoyl-dopamine, an "endovanilloid") also activate vanilloid VR1 receptors (coexpressed with cannabinoid CB(1) receptors), which excites sensory nerves and causes a release of sensory neurotransmitter. The fact that the activities of anandamide and N-arachidonoyl-dopamine span two distinct receptor families raises important questions about cannabinoid/vanilloid nomenclature, and as both compounds are structurally related to the archetypal vanilloid capsaicin, all three are arguably members of the same family of signalling molecules. Anandamide is released from nerves, but unlike classical neurotransmitters, it is not stored in and released from nerve vesicles, but is released on demand from the nerve cell membrane. In the central nervous system, cannabinoids function as retrograde signalling molecules, inhibiting via presynaptic cannabinoid CB(1) receptors the release of classical transmitter following release from the postsynaptic cell. At the neuroeffector junction, it is more likely that cannabinoids are released from prejunctional sites, as the neuroeffector junction is wide in some peripheral tissues and cannabinoids are rapidly taken up and inactivated. Understanding the actions of cannabinoids as modulators of peripheral neurotransmission is relevant to a variety of biological systems and possibly their disorders.
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Affiliation(s)
- Vera Ralevic
- School of Biomedical Sciences, Queen's Medical Centre, University of Nottingham Medical School, Nottingham NG7 2UH, UK.
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Vanessa Ho WS, Hiley CR. Vasodilator actions of abnormal-cannabidiol in rat isolated small mesenteric artery. Br J Pharmacol 2003; 138:1320-32. [PMID: 12711633 PMCID: PMC1573773 DOI: 10.1038/sj.bjp.0705160] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. The nonpsychoactive cannabinoid abnormal-cannabidiol (trans-4-[3-methyl-6-(1-methylethenyl)-2-cyclohexen-1-yl]-5-pentyl-1,3-benzenediol) (abn-cbd) produced concentration-dependent relaxation of methoxamine-precontracted rat small mesenteric artery. Endothelial removal reduced abn-cbd potency six-fold without affecting the maximum relaxation. 2. In endothelium-intact vessels, abn-cbd was less potent under 60 mM KCl-induced tone and inhibited by combination of L-N(G)-nitroarginine methyl ester (L-NAME) (nitric oxide synthase inhibitor; 300 micro M), apamin (small conductance Ca(2+)-activated K(+) channels inhibitor; 50 nM) and charybdotoxin (inhibitor of intermediate conductance Ca(2+)-activated K(+) channels and large conductance Ca(2+)-activated K(+) channels BK(Ca); 50 nM). L-NAME alone or in combination with either toxin alone had little effect. 3. In intact vessels, relaxations to abn-cbd were inhibited by SR 141716A (cannabinoid receptor antagonist; 1 or 3 micro M). Concomitant addition of L-NAME, apamin and charybdotoxin had no further effect. Other cannabinoid receptor antagonists either had little (SR 144528; 1 micro M and AM 251; 1 micro M) or no effect (AM 630; 10 micro M and AM 281; 1 micro M). Inhibition of gap junctions, G(i/o) protein coupling and protein kinase A also had no effect. 4. Endothelium-independent relaxation to abn-cbd was unaffected by L-NAME, apamin plus charybdotoxin or capsaicin (10 micro M). Abn-cbd inhibited CaCl(2)-induced contractions in vessels with depleted intracellular Ca(2+) stores and stimulated with methoxamine or KCl. This was insensitive to SR 141716A (3 micro M) but greatly reduced in vessels stimulated with ionomycin (Ca(2+) ionophore; 1 micro M). 5. We conclude that abn-cbd relaxes the rat small mesenteric artery by endothelium-dependent activation of K(+) channels via SR 141716A-sensitive pathways, which do not involve CB(1) and CB(2) receptors. It also causes endothelium-independent, SR 141716A-insensitive, relaxation by inhibiting Ca(2+) entry through voltage-gated Ca(2+) channels.
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Affiliation(s)
- W-S Vanessa Ho
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD
| | - C Robin Hiley
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD
- Author for correspondence:
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Li J, Kaminski NE, Wang DH. Anandamide-induced depressor effect in spontaneously hypertensive rats: role of the vanilloid receptor. Hypertension 2003; 41:757-62. [PMID: 12623992 DOI: 10.1161/01.hyp.0000051641.58674.f7] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
To test the hypothesis that activation of the vanilloid receptor (VR1) contributes to the anandamide-induced depressor effect in spontaneously hypertensive rats (SHR), we used a selective VR1 antagonist capsazepine (CAPZ) and a selective cannabinoid type 1 receptor antagonist SR141716A in conjunction with a VR1 agonist capsaicin in both SHR and Wistar-Kyoto rats (WKY). Mean arterial pressure was increased in SHR compared with WKY (P<0.05). Intravenous administration of capsaicin caused a greater depressor response in SHR compared with WKY (P<0.05), which was blocked by approximately 60% by CAPZ (P<0.05) in SHR only. Methanandamide caused a similar greater depressor response (P<0.05), which was blocked by approximately 50% and 60% by CAPZ and SR141716A, respectively, in SHR (P<0.05) but not in WKY. Radioimmunoassay showed that methanandamide increased plasma calcitonin gene-related peptide (CGRP) levels from baseline in both SHR and WKY (P<0.05), with no difference between 2 strains. Western blot showed that protein expression for the calcitonin receptor-like receptor-but not receptor activity modifying protein 1, VR1, and cannabinoid type 1 receptors-was increased in mesenteric resistance arteries in SHR compared with WKY (P<0.05). These data indicate that in addition to activation of cannabinoid type 1, anandamide may serve as an endogenous compound to stimulate VR1, leading to a decrease in blood pressure via CGRP release from sensory nerve terminals. Increased mesenteric CGRP receptor expression in SHR may account for increased sensitivity of blood pressure to anandamide and may serve as a compensatory response to buffer the increase in blood pressure in SHR.
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Affiliation(s)
- Jianping Li
- Department of Medicine and Pharmacology and Toxicology, Michigan State University, East Lansing 48824, USA
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Ralevic V, Jerman JC, Brough SJ, Davis JB, Egerton J, Smart D. Pharmacology of vanilloids at recombinant and endogenous rat vanilloid receptors. Biochem Pharmacol 2003; 65:143-51. [PMID: 12473388 DOI: 10.1016/s0006-2952(02)01451-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
This study compared the actions of members of five different chemical classes of vanilloid agonists at the recombinant rat vanilloid VR1 receptor expressed in HEK293 cells, and at endogenous vanilloid receptors on dorsal root ganglion cells and sensory nerves in the rat isolated mesenteric arterial bed. In mesenteric beds, vanilloids elicited dose-dependent vasorelaxation with the rank order of potency: resiniferatoxin>>capsaicin=olvanil>phorbol 12-phenyl-acetate 13-acetate 20-homovanillate (PPAHV)>isovelleral. Scutigeral was inactive. Responses were abolished by capsaicin pretreatment and inhibited by ruthenium red. In VR1-HEK293 cells and dorsal root ganglion neurones, Ca(2+) responses were induced by resiniferatoxin>capsaicin=olvanil>PPAHV; all four were full agonists. Isovelleral and scutigeral were inactive. The resiniferatoxin-induced Ca(2+) response had a distinct kinetic profile. Olvanil had a Hill coefficient of approximately 1 whilst capsaicin, resiniferatoxin and PPAHV had Hill coefficients of approximately 2 in VR1-HEK293 cells. The capsaicin-induced Ca(2+) response was inhibited in a concentration-dependent manner by ruthenium red>capsazepine>isovelleral. These data show that resiniferatoxin, capsaicin, olvanil and PPAHV, but not scutigeral and isovelleral, are agonists at recombinant rat VR1 receptors and endogenous vanilloid receptors on dorsal root ganglion neurones and in the rat mesenteric arterial bed. The vanilloids display the same relative potencies (resiniferatoxin>capsaicin=olvanil>PPAHV) in all of the bioassays.
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Affiliation(s)
- Vera Ralevic
- School of Biomedical Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham NG7 2UH, UK.
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Kunos G, Bátkai S, Offertáler L, Mo F, Liu J, Karcher J, Harvey-White J. The quest for a vascular endothelial cannabinoid receptor. Chem Phys Lipids 2002; 121:45-56. [PMID: 12505689 DOI: 10.1016/s0009-3084(02)00145-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This review examines pharmacological and biochemical evidence that suggests the existence of an as yet undefined endothelial receptor that mediates endocannabinoid-induced vasodilation. The signaling mechanisms triggered through this receptor and its potential physiological role are also discussed. Since vasodilation is often associated with hypotension, mechanisms involved in the hypotensive actions of cannabinoids, including the endocannabinoids anandamide and 2-arachidonoylglycerol, are also briefly reviewed.
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Affiliation(s)
- George Kunos
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, 12420 Parklawn Drive MSC-8115, Bethesda, MD 20892-8115, USA.
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