Myocardial Na+ during ischemia and accumulation of Ca2+ after reperfusion: a study with monensin and dichlorobenzamil.

The intracellular cation contents were determined in isolated perfused rat heart using cobaltic EDTA as a marker of the extracellular space. In hearts in which Na+ accumulation was induced with monensin, a Na+ ionophore, during 20 min-ischemia which otherwise did not result in accumulation of Na+, the levels of Na+ and Ca2+ were significantly higher after reperfusion with a significant decrease in K+. While the recovery of the cardiac mechanical function (CMF) was complete after reperfusion in control hearts, the recovery was incomplete in monensin-hearts. Dichlorobenzamil (DCB), the most specific inhibitor of Na(+)-Ca2+ exchanger, infused for 10 min before induction of ischemia in a dose of 10(-5) M, which produced a definite suppression of CMF (over 80%), inhibited the accumulation of Ca2+ and Na+ and the loss of K+ and ATP after 40 min-ischemia and reperfusion. The same dose of DCB given for 3 min before induction of ischemia and after reperfusion, which produced a less than 20% inhibition of CMF, failed to prevent the Ca2+ accumulation after 40 min-ischemia and reperfusion. These findings are at variance with the idea that the accumulation of Na+ during ischemia and the consequent augmented operation of Na(+)-Ca2+ exchange is responsible for accumulation of Ca2+ after reperfusion.
AuthorsT Kawada, Y Yoshida, H Sakurai, S Imai
JournalJapanese journal of pharmacology (Jpn J Pharmacol) Vol. 59 Issue 2 Pg. 191-200 (Jun 1992) ISSN: 0021-5198 [Print] JAPAN
PMID1434115 (Publication Type: Journal Article)
Chemical References
  • Adenine Nucleotides
  • 3',4'-dichlorobenzamil
  • Amiloride
  • Monensin
  • Sodium
  • Potassium
  • Calcium
  • Adenine Nucleotides (metabolism)
  • Amiloride (analogs & derivatives, pharmacology)
  • Animals
  • Calcium (metabolism)
  • In Vitro Techniques
  • Ion Transport (drug effects)
  • Male
  • Monensin (pharmacology)
  • Myocardial Ischemia (metabolism, physiopathology)
  • Myocardial Reperfusion Injury (metabolism, physiopathology)
  • Myocardium (metabolism)
  • Perfusion
  • Potassium (metabolism)
  • Rats
  • Sodium (metabolism)

Join CureHunter, for free Research Interface BASIC access!

Take advantage of free CureHunter research engine access to explore the best drug and treatment options for any disease. Find out why thousands of doctors, pharma researchers and patient activists around the world use CureHunter every day.
Realize the full power of the drug-disease research network!

Choose Username:
Verify Password: