The influence of exaprolol upon the ischaemic rat heart and its interaction with sarcolemmal (Na+ + K+)-ATPase.
The capability of cyclohexylphenol exaprolol of protecting the ischaemic myocardium during ischaemic cardiac arrest was assessed in the isolated working rat heart. Exaprolol added to the perfusion medium in a dose of 10(-7) mol.l-1 only minimally influenced the left ventricular function (reduced the stroke volume by 18.84% and cardiac output by 14.63%). The hearts were subjected to global ischaemia for 75 min at 26 degrees C and subsequently reperfused for 60 min at 37 degrees C. The recovery of left ventricular function following reperfusion, expressed as a percentage of preischaemic functional performance was used as an indicator of the ischaemic tolerance of the heart. The effect of exaprolol on sarcolemmal (Na+ + K+)-, Mg2+- and Ca2+-ATPase activities was also examined. Exaprolol-pretreated hearts revealed better postischaemic recovery of the left ventricular dP/dt max and stroke volume as well as improved efficiency in the transformation of chemical energy to mechanical work. Exaprolol in 10(-4) mol.l-1 concentration significantly stimulated the specific activity of sarcolemmal (Na+ + K+)-ATPase. Possible mechanisms of the salutary effect of exaprolol on the ischaemic heart are discussed.
Dzurba
A
A
Centre of Physiological Sciences, Slovak Academy of Sciences, Bratislava.
Barta
E
E
Styk
J
J
Okolicány
J
J
Ziegelhöffer
A
A
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology / Q000627:therapeutic use*; D000818:Animals; D001783:Blood Flow Velocity / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D002302:Cardiac Output / Q000187:drug effects; D003327:Coronary Disease / Q000188:drug therapy*; D006321:Heart / Q000187:drug effects; D008297:Male; D011412:Propanolamines / Q000494:pharmacology / Q000627:therapeutic use*; D051381:Rats; D011919:Rats, Inbred Strains; D012508:Sarcolemma / Q000187:drug effects / Q000201:enzymology*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D013318:Stroke Volume / Q000187:drug effects
D000319:Adrenergic beta-Antagonists; D011412:Propanolamines; D000254:Sodium-Potassium-Exchanging ATPase; C012969:exaprolol