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Extracellular ATP signaling in equine digital blood vessels

Zerpa, Hector, Crawford, Carol, Knight, Gillian E., Fordham, Alice F., Janska, Silvia E., Peppiatt-Wildman, Claire M., Elliott, Jonathan, Burnstock, Geoffrey, Wildman, Scott S.P. (2013) Extracellular ATP signaling in equine digital blood vessels. European Journal of Pharmacology, 702 (1-3). pp. 242-249. ISSN 0014-2999. (doi:10.1016/j.ejphar.2013.01.018) (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided. (Contact us about this Publication)
Official URL
http://doi.org/10.1016/j.ejphar.2013.01.018

Abstract

The functional distribution of ATP-activated P2 receptors is well characterized for many blood vessels, but not in the equine digital vasculature, which is a superficial vascular bed that displays thermoregulatory functions and has been implicated in ischemia-reperfusion injuries of the hoof. Isolated equine digital arteries (EDA) and veins (EDV) were submitted to isometric tension studies, whereby electric field stimulation (EFS) and concentration-response curves to exogenously applied agonists were constructed under low tone conditions. Additionally, immunofluorescent localization of P2X and P2Y receptor subtypes was performed. EFS-induced constriction was abolished by tetrodotoxin (1 ?M, n=4). Endothelium denudation did not modify the EFS-induced constriction (n=3). The EFS-induced constriction in EDA was inhibited by phentolamine (67.7±1.8%, n=6; 10 ?M), and by the non-selective P2 receptor antagonist suramin (46.2±1.3%, n=6; 10 ?M). EFS-induced constriction in EDV was reduced by suramin (48.2±2.4%, n=6; 10 ?M), the P2 receptor antagonist pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid (58.3±4.5%, n=6; 10 ?M), and phentolamine (23.2±2.5%, n=6; 10 ?M). Exogenous methoxamine and ATP mimicked EFS-induced constriction in EDA and EDV. Immunostaining for P2X1, P2X2 and P2X3, and, for P2X1 and P2X7 receptor subunits were observed in EDA and EDV smooth muscle and adventitia, respectively. ATP and noradrenaline are co-transmitters in sympathetic nerves supplying the equine digital vasculature, noradrenaline being the dominant agonist in EDA, and ATP in EDV. In conclusion, P2X receptors mediate vasoconstriction in EDA and EDV, although different P2X subunits are involved in these vessels. The physiological significance of this finding in relation to thermoregulatory functions and equine laminitis is discussed.

Item Type: Article
DOI/Identification number: 10.1016/j.ejphar.2013.01.018
Uncontrolled keywords: Adenosine 5?-triphosphate; Neurotransmission; Noradrenaline; P2 receptor; Purinoceptor; Purinergic; Sympathetic nerve; Equine digitalvasculature; Laminitis
Subjects: R Medicine > RM Therapeutics. Pharmacology
Divisions: Faculties > Sciences > Medway School of Pharmacy
Depositing User: Scott S.P. Wildman
Date Deposited: 13 Dec 2015 14:03 UTC
Last Modified: 29 May 2019 16:42 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/53064 (The current URI for this page, for reference purposes)
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