Endothelin-1 and -3 cause endothelium-dependent hyperpolarization in the rat mesenteric artery

Am J Physiol. 1993 Dec;265(6 Pt 2):H2137-41. doi: 10.1152/ajpheart.1993.265.6.H2137.

Abstract

The present study was designed to determine whether endothelin (ET) induces endothelium-dependent hyperpolarization in the isolated rat mesenteric artery and, if so, to identify the receptor subtype involved. Main superior mesenteric arteries of Wistar-Kyoto and spontaneously hypertensive rats were used for the measurement of electrical responses of smooth muscle cells, using glass microelectrode. In tissues with endothelium of both strains, ET-1 (10(-8) M) caused an initial transient hyperpolarization followed by a sustained depolarization. In tissues without endothelium, only depolarization was observed. ET-3 (10(-8) M) produced transient hyperpolarizations only in preparations with endothelium. There was no significant difference in maximal amplitude of hyperpolarization between the two strains. BQ-123 (selective ETA-receptor antagonist) blocked the depolarization to ET-1 but did not inhibit hyperpolarizing responses to either isopeptide. IRL-1620 (specific ETB-receptor agonist) produced transient membrane hyperpolarizations in tissues with endothelium. The hyperpolarizations induced by ET were not affected by NG-nitro-L-arginine. These data suggest that both ET-1 and ET-3 can cause endothelium-dependent hyperpolarization in the rat mesenteric artery and that the endothelial receptor involved may belong to ETB subtype.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Biological Factors / metabolism
  • Electrophysiology
  • Endothelins / pharmacology*
  • Endothelium, Vascular / drug effects*
  • Endothelium, Vascular / metabolism
  • Endothelium, Vascular / physiology
  • Male
  • Mesenteric Arteries / drug effects*
  • Mesenteric Arteries / metabolism
  • Mesenteric Arteries / physiology
  • Rats
  • Rats, Inbred SHR
  • Rats, Inbred WKY
  • Receptors, Endothelin / physiology

Substances

  • Biological Factors
  • Endothelins
  • Receptors, Endothelin
  • endothelium-dependent hyperpolarization factor