Effects of endothelin on the electrical activity of sino-atrial pacemaker cells of rabbit

Zhao Zhang, Yu Long Li, Shiu Yong Ho

Research output: Contribution to journalArticlepeer-review

2 Scopus citations

Abstract

The effects of endothelin-1 (ET-1) on the electrophysiological activity of pacemaker cells of rabbit sino-atrial node were examined by using intracellular microelectrode technique. The results obtained were as follows : (1) With superfusion of ET-1 (1-30 nmol/L), the velocity of diastolic depolarization (VDD) of pacemaker cells was significantly decreased in a concentration dependent manner, resulting in a reduced rate of pacemaker firing (RPF). (2) The decreases in RPF and VDD induced by ET-1 could be virtually blocked by pretreatment with ET(A) receptor blocker BQ-123 (20 or 100 μg/L). It was strongly suggested that the electrophysiological effects of ET-1 on the pacemaker cells were mediated by the ET(A) receptor. (3) The negative chronotropic action of ET-1 on the pacemaker cells was totally abolished by pretreatment with a kind of K(ATP) channel blocker glibenclamide (10 μmol/L). On the basis of above results, it appears that the binding of ET-1 with ET(A) receptor may induce an activation of K(ATP) channels with resultant increase in K+ current so as to decrease the velocity of diastolic depolarization in the pacemaker cells.

Original languageEnglish (US)
Pages (from-to)53-58
Number of pages6
JournalActa Physiologica Sinica
Volume48
Issue number1
StatePublished - 1996
Externally publishedYes

Keywords

  • BQ-123
  • electrophysiology
  • endothelin
  • endothelin receptor
  • glibenclamide
  • sino-atrial node

ASJC Scopus subject areas

  • Medicine(all)

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