Relation between spontaneous contraction and sarcoplasmic reticulum function in cultured neonatal rat cardiac myocytes

Cell Signal. 1998 May;10(5):349-54. doi: 10.1016/s0898-6568(97)00134-4.

Abstract

The relation between spontaneous contraction, Ca2+ oscillations, and sarcoplasmic reticulum (SR) function was studied in cultured neonatal rat cardiac myocytes. Spontaneous contraction and Ca2+ oscillations were irregular at day 2 of culture but became regular at day 6 of culture in neonatal rat cardiac myocytes. The rate of spontaneous contraction and the frequency of Ca2+ oscillations were decreased by verapamil and were abolished in the absence of extracellular Ca2+ at both day 2 and day 6 of culture. Ryanodine and thapsigargin increased the rate of contraction and the frequency of Ca2+ oscillations at day 2 of culture but did not affect contractions and Ca2+ oscillations at day 6 of culture. Ultrastructural observation showed that the structure of SR developed less at day 6 of culture. The present results suggest that spontaneous contraction and Ca2+ oscillations are due mainly to extracellular Ca2+ influx but not to Ca2+ release from SR in neonatal rat cardiac myocytes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Animals, Newborn
  • Calcium / metabolism
  • Calcium / pharmacology
  • Cells, Cultured
  • Heart / physiology*
  • Myocardial Contraction / physiology*
  • Myocardium / cytology
  • Myocardium / metabolism
  • Rats
  • Rats, Wistar
  • Ryanodine / pharmacology
  • Sarcoplasmic Reticulum / metabolism
  • Sarcoplasmic Reticulum / physiology*
  • Thapsigargin / pharmacology

Substances

  • Ryanodine
  • Thapsigargin
  • Calcium