Exercise training alters the Ca2+ and contractile responses of coronary arteries to endothelin

D. K. Bowles, M. H. Laughlin, M. Sturek

Research output: Contribution to journalArticle

36 Scopus citations

Abstract

We tested the hypothesis that alterations in myoplasmic free Ca2+ (Ca(m)) regulation in coronary smooth muscle after exercise training (Ex) underlie changes in vasomotor function. Yucatan miniature pigs were endurance trained by treadmill running for 16-20 wk. Simultaneous determination of Ca(m) (fura-2 microfluorometry) and contraction during endothelin exposure in coronary arteries were then performed. Endothelin (10-9 to 10-7 M) was administered either cumulatively or as a single concentration. Ex significantly attenuated the Ca(m) response to 10-9 and 10-8 M endothelin. Developed tension was significantly diminished at 10-8 M endothelin in Ex pigs, producing a rightward shift in the concentration- developed tension response. Attenuated Ca(m) and contractile response to 10- 8 M endothelin were present after Ex whether endothelin was applied cumulatively or as a single concentration. The developed tension-Ca(m) relationship showed an increased Ca(m) sensitivity of contraction with Ex. Endothelin (10-8 M)-induced Ca2+ influx, estimated by Ba2+ influx in low-Na+ solution, was increased threefold in coronary arteries from Ex pigs. The decreased Ca(m) in the presence of increased divalent cation (i.e., Ca2+) influx during 10-8 M endothelin suggests a greatly enhanced sarcolemmal Ca2+ cycling in coronary arteries from Ex pigs.

Original languageEnglish (US)
Pages (from-to)1079-1087
Number of pages9
JournalJournal of Applied Physiology
Volume78
Issue number3
DOIs
StatePublished - Jan 1 1995
Externally publishedYes

Keywords

  • barium
  • calcium cycling
  • calcium influx
  • calcium localization
  • fura 2
  • porcine
  • sarcolemma
  • vascular smooth muscle
  • vasoconstriction

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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