Effect of hydralazine on tension and membrane potential in the rat caudal artery

K. Hermsmeyer, A. Trapani, P. W. Abel, M. Worcel

Research output: Contribution to journalArticle

16 Scopus citations

Abstract

To determine whether the vasodilator, hydralazine (HYD), produces hyperpolarization of vascular muscle cells, we measured the effect of HYD on membrane potential and contractile responses to phenylephrine and K+. HYD (1 μM) caused a 4 mV hyperpolarization of phenylephrine-depolarized arteries (compared with controls without HYD), which could possibly account for up to three-fourths of the 39% decrease in tension measured. K+-contracted vessels were also 34% relaxed by 1 μM HYD without an effect on membrane potential. In addition, HYD further relaxed phenylephrine-stimulated vessels previously relaxed by D-600, suggesting that Ca++ channel blockade may not be an important mechanism of vasodilation for HYD. The evidence suggests that a nonmembrane action of HYD on arterial muscle probably multiplies the relaxant effect of membrane potential hyperpolarization. Both mechanisms would attenuate the effects of adrenergic stimulation.

Original languageEnglish (US)
Pages (from-to)322-326
Number of pages5
JournalJournal of Pharmacology and Experimental Therapeutics
Volume227
Issue number2
StatePublished - Dec 1 1983
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Molecular Medicine
  • Pharmacology

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