Non-adrenergic vasoconstriction and vasodilatation of guinea-pig aorta by β-phenylethylamine and amphetamine – role of nitric oxide determined with L-NAME and NO scavengers

Broadley, Kenneth ORCID: https://orcid.org/0000-0002-3339-2050 and Broadley, Harrison D. 2018. Non-adrenergic vasoconstriction and vasodilatation of guinea-pig aorta by β-phenylethylamine and amphetamine – role of nitric oxide determined with L-NAME and NO scavengers. European Journal of Pharmacology 818 , pp. 198-205. 10.1016/j.ejphar.2017.10.038

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Abstract

Sympathomimetic and trace amines, including β-phenylethylamine (PEA) and amphetamine, increase blood pressure and constrict isolated blood vessels. By convention this is regarded as a sympathomimetic response, however, recent studies suggest trace amine-associated receptor (TAAR) involvement. There is also uncertainty whether these amines also release nitric oxide (NO) causing opposing vasodilatation. These questions were addressed in guineapig isolated aorta, a species not previously examined. Guinea-pig aortic rings were set up to measure contractile tension. Cumulative concentration-response curves were constructed for the reference α-adrenoceptor agonist, phenylephrine, PEA or d-amphetamine before and in the presence of vehicles, the α1-adrenoceptor antagonist, prazosin (1 μM), the nitric oxide synthase inhibitor, Nω-nitro-L-arginine (L-NAME), or NO scavengers, curcumin and astaxanthin. Prazosin inhibited phenylephrine contractions with low affinity consistent with α1L-adrenoceptors. However, PEA and amphetamine were not antagonised, indicating nonadrenergic responses probably via TAARs. L-NAME potentiated contractions to PEA both in the absence and presence of prazosin, indicating that PEA releases NO to cause underlying opposing vasodilatation, independent of α1-adrenoceptors. L-NAME also potentiated amphetamine and phenylephrine. PEA was potentiated by the NO scavenger astaxanthin but less effectively. Curcumin, an active component of turmeric, however, inhibited PEA. Trace amines therefore constrict blood vessels non-adrenergically with an underlying NO-mediated non-adrenergic vasodilatation. This has implications in the pressor actions of these amines when NO is compromised.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Pharmacy
Publisher:	Elsevier
ISSN:	0014-2999
Date of First Compliant Deposit:	27 October 2017
Date of Acceptance:	20 October 2017
Last Modified:	06 Nov 2023 23:48
URI:	https://orca.cardiff.ac.uk/id/eprint/106013

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