[Effect of nonselective beta-adrenoblocker carvedilol on extrasystolic and postextrasystolic contractility in the rat myocardium after experimental infarction].
Features of the extrasystolic and postextrasystolic contractility of myocardium isolated from rats aged 4 months (group I, n = 30) and 12 months (group II, n = 30) after postinfarction remodeling of the heart (PIRH) and long-term treatment with carvedilol have been studied. Each age group included in 10 intact control animals, 10 animals with postinfarction cardiosclerosis (PICS), and 10 rats with PICS treated with carvedilol (2.1 mg/kg) during 28 days, beginning with the 45th day after coronary occlusion. The isometric contractility of myocardium was monitored at an electric stimulation frequency of 0.5 Hz. The extrasystolic effect was produced by an electric pulse applied within 0.2 - 5 s interval after the basic stimulation. It is established that the inotropic response of myocardium to the extrasystolic impulse exhibits age-dependent features both the intact rats and in the rats with PICS. The differences can be related to the age-dependent involvement of the ion-transport systems of sarcolemma and sarcoplasmic reticulum into the modulation of excitation--contractility coupling during PIRH. The long-term treatment with carvedilol led to restoration of the Ca(2+)-accumulation reserve of sarcoplasmic reticulum to the age-normal level in young animalsand decreased the risk of development of hemodynamically significant heart rate disturbances in old rats.
Afanas'ev
S A
SA
Kondrat'eva
D S
DS
Putrova
O D
OD
Perchatkin
V A
VA
Repin
A N
AN
Popov
S V
SV
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000367:Age Factors; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002227:Carbazoles / Q000494:pharmacology*; D000077261:Carvedilol; D004558:Electric Stimulation; D042541:Intracellular Space / Q000378:metabolism; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects*; D009203:Myocardial Infarction / Q000378:metabolism / Q000503:physiopathology*; D009206:Myocardium / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000378:metabolism; D011412:Propanolamines / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D020257:Ventricular Remodeling / Q000187:drug effects
D000319:Adrenergic beta-Antagonists; D002227:Carbazoles; D011412:Propanolamines; D000077261:Carvedilol; D002118:Calcium