Evidence for different 5-HT1B/1D receptors mediating vasoconstriction of equine digital arteries and veins.
Abstract: 5-hydroxytryptamine (5-HT) is a potent vasoconstrictor of equine digital arteries and veins which may play a role in the ischaemic disease, laminitis. The present investigation compared the properties of 5-HT1B/1D receptors in arteries with those in veins using isolated rings of equine digital blood vessels. The 5-HT1B/1D receptor-selective agonists, anpirtoline and sumatriptan were 17.9 and 10 times more potent and produced 4.1 and 5.6 times greater maximum contractions, respectively, in veins when compared to arteries. Other agonists tested were of equal potency and produced the same maximum responses in veins and arteries. Propranolol competitively inhibited 5-HT1B/1D receptor mediated responses in arteries, with a pKB of 6.7, but had no significant effects on responses in veins at 1 microM. Metergoline competitively inhibited 5-HT1B/1D receptor mediated responses in veins, with a pKB of 8.1, but had no significant effect in arteries at 0.1 microM. These data suggest that 5-HT1B/1D receptors mediating vasoconstriction in equine digital arteries are pharmacologically different to those found in digital veins.
Publication Date: 1998-10-06 PubMed ID: 9760032DOI: 10.1016/s0014-2999(98)00520-2Google Scholar: Lookup
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- Comparative Study
- Journal Article
- Research Support
- Non-U.S. Gov't
Summary
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This research paper explores the different actions of 5-hydroxytryptamine (5-HT), a potent vasoconstrictor, on equine digital arteries and veins, suggesting that these distinct reactions may contribute to equine ischaemic disease, laminitis.
Introduction and Aim
- 5-hydroxytryptamine (5-HT), or serotonin, is a potent vasoconstrictor (a substance that narrows blood vessels) and is involved in the regulation of equine digital arteries and veins.
- Changes in blood flow to the equine digit (hooves) can result in laminitis, a painful ischaemic (lack of blood supply) disease in horses.
- The main objective of the study was to determine whether 5-HT acts differently on arteries and veins within equine digits, by comparing properties of 5-HT1B/1D receptors in these distinct blood vessels.
Methods
- The researchers used isolated ring samples of equine digital arteries and veins to perform their experiment.
- The samples were exposed to the 5-HT1B/1D receptor-selective agonists anpirtoline and sumatriptan, along with several other agonists.
- The researchers also tested the effects of propranolol and metergoline, two drugs known to interact with 5-HT receptors.
Results
- Anpirtoline and sumatriptan were found to be significantly more potent and induced considerably larger maximum contractions in veins compared to arteries.
- Other agonists tested displayed equivalent potency and induced identical maximum responses in both veins and arteries.
- Propranolol was found to competitively inhibit responses mediated by 5-HT1B/1D receptor in arteries but displayed no significant effects on venous responses.
- Metergoline competitively inhibited responses in veins mediated by 5-HT1B/1D receptor, but no significant effect was observed in arterial reactions.
Conclusion
- These findings indicate that 5-HT1B/1D receptors present in equine digital arteries and veins respond differently to various substances, suggesting that they are pharmacologically different.
- This divergence in receptor responses could play a role in the disease process of laminitis.
Cite This Article
APA
Bailey SR, Elliott J.
(1998).
Evidence for different 5-HT1B/1D receptors mediating vasoconstriction of equine digital arteries and veins.
Eur J Pharmacol, 355(2-3), 175-187.
https://doi.org/10.1016/s0014-2999(98)00520-2 Publication
Researcher Affiliations
- Department of Veterinary Basic Sciences, Royal Veterinary College, London, UK.
MeSH Terms
- Animals
- Arteries / drug effects
- Arteries / physiology
- Hindlimb
- Horses
- Receptor, Serotonin, 5-HT1B
- Receptor, Serotonin, 5-HT1D
- Receptors, Serotonin / drug effects
- Receptors, Serotonin / physiology
- Serotonin Agents / pharmacology
- Vasoconstriction
- Veins / drug effects
- Veins / physiology
Citations
This article has been cited 4 times.- Mulcahy L, Tudor E, Bailey SR. Validation of canine uterine and testicular arteries for the functional characterisation of receptor-mediated contraction as a replacement for laboratory animal tissues in teaching. PLoS One 2020;15(5):e0230516.
- Klotz JL, McDowell KJ. Tall fescue ergot alkaloids are vasoactive in equine vasculature. J Anim Sci 2017 Nov;95(11):5151-5160.
- Menzies-Gow NJ, Wray H, Bailey SR, Harris PA, Elliott J. The effect of tumour necrosis factor-α and insulin on equine digital blood vessel function in vitro. Inflamm Res 2014 Aug;63(8):637-47.
- Srinivasan SY, Illera PA, Kukhtar D, Benseny-Cases N, Cerón J, Álvarez J, Fonteriz RI, Montero M, Laromaine A. Arrhythmic Effects Evaluated on Caenorhabditis elegans: The Case of Polypyrrole Nanoparticles. ACS Nano 2023 Sep 12;17(17):17273-17284.
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