Equine coronary artery responds to 5‐hydroxytryptamine with relaxation in vitro

Obit, T.; Kabeyama, Atsushi; Nishio, Akira

doi:10.1111/j.1365-2885.1994.tb00236.x

Cited by 10 publications

(6 citation statements)

References 27 publications

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“…, 1991). Equine coronary arteries have also been shown to relax in response to 5‐HT, partially mediated by endothelial 5‐HT 2 receptors (Obi et al. , 1994; Bailey, 1998).…”

Section: Discussionmentioning

confidence: 99%

“…Secondly, 5-HT has also been shown to stimulate NO production by endothelial cells through activation of 5-HT 1 -like, 5-HT 2 and 5-HT 7 receptor subtypes on endothelial cells of blood vessel of differing origin from various species (Verbeuren et al, 1991). Equine coronary arteries have also been shown to relax in response to 5-HT, partially mediated by endothelial 5-HT 2 receptors (Obi et al, 1994;Bailey, 1998). Preconstricted isolated large equine digital arteries, on the other hand, failed to relax in response to 5-HT (Bailey, 1998).…”

Section: Discussionmentioning

confidence: 99%

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Assessment of endothelium‐dependent vasodilation in equine digital resistance vessels

Berhane

Elliott

Bailey

2006

Vet Pharm & Therapeutics

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Haemodynamic disturbances leading to ischaemia and reperfusion injury of the digit are thought to be involved in the pathophysiology of acute equine laminitis. Identification of physiological regulators of blood flow through the equine digit is important in identifying factors, which may predispose animals to laminitis. A method was developed to assess endothelium-dependent responses of the isolated Krebs-perfused equine digit by co-administration of 5-hydroxytryptamine (5-HT) with vasodilator agents, carbachol (CCh), bradykinin (BK) and substance P (SP). Bolus co-administration of CCh (0.02-2 micromol), BK and SP (0.02-0.2 nmol), caused inhibition of the 5-HT pressor response by 50-60%. The vasodilator responses were abolished by the detergent, CHAPS, indicating endothelium dependency; whereas vasoconstrictor responses to 5-HT were potentiated. CCh-induced relaxation was significantly reduced by the nitric oxide synthase inhibitor L-NAME (79.7 +/- 3.4% inhibition), whereas a large proportion of BK and SP-induced relaxation remained (34.1 +/- 6.3% and 33.6 +/- 5.3% inhibition). L-NAME potentiated vasoconstrictor responses to 5-HT. In conclusion, this study demonstrates that endothelium-derived NO modulates the response to vasoconstrictors such as 5-HT and is likely to be an important regulator of blood flow in the digital resistance vascular bed. Other factor(s) released by the endothelium are also important in regulating blood flow, whose identity remains to be established.

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“…, 1991). Equine coronary arteries have also been shown to relax in response to 5‐HT, partially mediated by endothelial 5‐HT 2 receptors (Obi et al. , 1994; Bailey, 1998).…”

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Assessment of endothelium‐dependent vasodilation in equine digital resistance vessels

Berhane

Elliott

Bailey

2006

Vet Pharm & Therapeutics

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“…There are examples in which 5-HT relaxant receptors are revealed without blockade of contractile 5-HT receptors. This includes the equine coronary artery (Obi et al, 1994) and dog coronary artery (Terrón, 1996). Although no antagonists of contractile 5-HT receptors were added in the equine coronary artery studies, Terrón (1996) showed that whereas 5-HT relaxation was present naturally in the dog coronary artery, the sensitivity to 5-HT and 5-carboxamidotryptamine (5-CT) as relaxants was increased when the 5-HT 1B/1D receptor antagonist N-[4-methoxy-3-(4-methyl-1-piperazinyl)phenyl]-2Ј-methyl-4Ј-(5-methyl-1,2,4-oxadiazol-3-yl)-1-1Ј-biphenyl-4-carboxamide (GR127935) was added.…”

Section: -Hydroxytryptamine Synthesis and Handlingmentioning

confidence: 99%

Serotonin and Blood Pressure Regulation

Watts

Morrison

Davis

et al. 2012

Pharmacological Reviews

321

262

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“…Serotonin reportedly induced basilar arterial contraction via the 5-HT 1 receptor in the Habu snake [18] and was involved in pulmonary vascular responses (a study with no receptor mediation) in the file snake (Acrochordus granulatus) [35]. Many vascular responses to serotonin are constrictive, but reported responses also include relaxation in the rat jugular vein [36,37], pig pulmonary artery [38,39], and equine coronary artery [40]. Although serotonin-induced relaxation responses vary between animal species and blood vessels, 5-HT 1 , 5-HT 2 , and 5-HT 7 receptors and endothelial cell-derived NO all appear to be involved [34,[36][37][38][39][40].…”

Section: Discussionmentioning

confidence: 99%

“…Many vascular responses to serotonin are constrictive, but reported responses also include relaxation in the rat jugular vein [36,37], pig pulmonary artery [38,39], and equine coronary artery [40]. Although serotonin-induced relaxation responses vary between animal species and blood vessels, 5-HT 1 , 5-HT 2 , and 5-HT 7 receptors and endothelial cell-derived NO all appear to be involved [34,[36][37][38][39][40]. In further experiments with antagonists and inhibitors that effectively yielded serotonin-induced relaxation, the combination of L-NNA, SB269970, methiothepin, or ketanserin inhibited serotonin-induced relaxation at low concentrations but not at high concentrations (Figure 5A).…”

Section: Discussionmentioning

confidence: 99%

Characterization of Vasoreactivity in a Semi-Arboreal Snake, the Tokara Habu (Protobothrops tokarensis)

Ootawa,

Wu,

Sekio

et al. 2023

Animals

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Vasoreactivity is relatively well documented in terrestrial snakes but has previously been investigated in only one semi-arboreal snake species. Consequently, the extent to which vasoreactivity is common across snake taxa or varies by habitat is unclear. The Tokara habu (Protobothrops tokarensis) is a semi-arboreal snake endemic to only two small adjacent Japanese islands, and hence a useful species for further investigation of vasoreactivity. We evaluated responses to known vasoactive substances in thoracic aortas isolated from Tokara habu. Under resting tension, noradrenaline and angiotensin II induced concentration-dependent contraction, but acetylcholine, serotonin (5-hydroxytriptamine; 5-HT), and isoproterenol induced relaxation followed by contraction. Histamine and rattlesnake bradykinin had no effect. Experiments with receptor-specific antagonists suggest that M1 and M3 receptors are involved in the acetylcholine-induced response; 5-HT1, 5-HT2, and 5-HT7 receptors in the serotonin-induced response; and β1 and β2 adrenoceptors in isoproterenol-induced relaxation. This is the first report on such response patterns in snakes (including serotonin- and isoproterenol-induced relaxation). Nitric oxide may be involved in acetylcholine-induced relaxation but not in the responses to serotonin or isoproterenol. In contrast to the uniform vasoreactivity observed in terrestrial snakes, the vasoreactivity of semi-arboreal snakes may be governed by diverse regulatory mechanisms.

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Equine coronary artery responds to 5‐hydroxytryptamine with relaxation in vitro

Cited by 10 publications

References 27 publications

Assessment of endothelium‐dependent vasodilation in equine digital resistance vessels

Assessment of endothelium‐dependent vasodilation in equine digital resistance vessels

Serotonin and Blood Pressure Regulation

Characterization of Vasoreactivity in a Semi-Arboreal Snake, the Tokara Habu (Protobothrops tokarensis)

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