Temperature-sensitive adenosine-mediated vasoconstriction in the skin microcirculation

I. Stojanov, K. G. Proctor

Research output: Contribution to journalArticle

10 Scopus citations

Abstract

The A1 and A2 adenosine receptor agonists (5'-(N-ethylcarboxamido)-adenosine, 2-chloroadenosine, adenosine (ADO) and N6-cyclohexyladenosine) were topically appled to 30- to 60-μm arterioles in the s.c. microcirculation of hamsters at different skin temperatures. Vasoconstrictor responses evoked by nanomolar concentrations of ADO and N6-cyclohexyladenosine were enhanced when local skin temperature (T(s)) was increased, but unchanged when T(s) was decreased. All these responses were antagonized by 8-phenyltheophylline, which suggests that temperature-sensitive vasoconstrictions were mediated by A1 receptors. In contrast, norepinephrine (10-7 M) caused vasoconstrictions that were not enhanced at high T(s) and were markedly reduced at low T(s), while angiotensin II (10-8 M) caused vasoconstrictions that were temperature-insensitive. Vasodilator responses evoked by micromolar concentrations of ADO, 2-chloroadenosine and 5'-(N-ethylcarboxamido)-adenosine were temperature-insensitive. All these responses were antagonized by 8-phenyltheophylline, except those mediated by 10-6 to 10-4 M ADO, which can be explained by simple override of the receptor blockade. Thus, A1, but not A2, receptors show temperature-dependent actions in vivo, which suggests that temperature sensivitity could be an additional criterion for classification of ADO receptors.

Original languageEnglish (US)
Pages (from-to)1083-1089
Number of pages7
JournalJournal of Pharmacology and Experimental Therapeutics
Volume253
Issue number3
StatePublished - Jan 1 1990
Externally publishedYes

ASJC Scopus subject areas

  • Molecular Medicine
  • Pharmacology

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