Effects of procaine and caffeine on the contractility of enzymatically isolated myocytes and intact cardiac tissue.
1. Procaine and caffeine exerted opposite effects on the contractility of rat cardiac tissue. 2. Procaine enhanced and caffeine depressed isometric contractile force of right ventricular strips. 3. In enzymatically isolated cells, caffeine increased the frequency and decreased the amplitude of spontaneous contractions, while procaine retarded the beating rate but concomitantly raised the shortening amplitude of the myocyte. 4. Both drugs depressed the propagation velocity of the contractile waves. 5. The results are suggested to be due to the opposite effects of the two drugs on the Ca-release process of the sarcoplasmic reticulum.
Vornanen
M
M
Department of Biology, University of Joensuu, Finland.
D000818:Animals; D002110:Caffeine / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D004562:Electrocardiography; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D066298:In Vitro Techniques; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects*; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D011343:Procaine / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012519:Sarcoplasmic Reticulum / Q000378:metabolism
D002110:Caffeine; D011343:Procaine; D002118:Calcium