Increase in junctional conductance caused by isoproterenol in heart cell pairs is suppressed by cAMP-dependent protein-kinase inhibitor.
The influence of isoproterenol (10(-6) M) on junctional conductance of cell pairs isolated from adult rat ventricle was investigated using two separated voltage-clamp circuits. The drug increased the junctional conductance by 40% (S.E. +/- 11%) (n = 10) within 20 sec. In experiments in which an inhibitor of cAMP dependent-protein Kinase was introduced into the cells the effect of isoproterenol on junctional conductance was totally suppressed. These results support the view that cAMP involved in the fast-modulation of junctional conductance in heart and that the activation of a protein Kinase is needed for the effect of the nucleotide on junctional conductance.
De Mello
W C
WC
Department of Pharmacology, Medical Sciences Campus, San Juan, Puerto Rico.
D000818:Animals; D002352:Carrier Proteins / Q000494:pharmacology*; D000242:Cyclic AMP / Q000378:metabolism; D004553:Electric Conductivity; D006321:Heart / Q000187:drug effects* / Q000502:physiology; D006329:Heart Conduction System / Q000187:drug effects; D047908:Intracellular Signaling Peptides and Proteins; D007545:Isoproterenol / Q000494:pharmacology*; D051381:Rats
D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; C015482:protein kinase modulator; D000242:Cyclic AMP; D007545:Isoproterenol