RT Journal Article
SR Electronic
T1 CATECHOLAMINE STORES OF THE ISOLATED RAT HEART PERFUSED WITH SUBSTRATE-FREE MEDIUM
JF Journal of Pharmacology and Experimental Therapeutics
JO J Pharmacol Exp Ther
FD American Society for Pharmacology and Experimental Therapeutics
SP 96
OP 101
VO 177
IS 1
A1 NARANJAN S. DHALLA
A1 BUDH D. BHAGAT
A1 PRAKASH V. SULAKHE
A1 ROBERT E. OLSON
YR 1971
UL http://jpet.aspetjournals.org/content/177/1/96.abstract
AB An isolated rat heart perfused with substratefree medium failed to generate contractile force after a period of two hours. In hearts taken from animals pretreated with 3H-norepinephrine, endogenous norepinephrine in the substrate-depleted heart declined to about 60% of the control value without changes in the specific activity of 3H-norepinephrine. 3H-norepinephrine in the granular fraction decreased and 3H-norepinephrine in the soluble fraction increased after perfusing the heart with substrate-free medium. Perfusion of hearts with medium containing glucose maintained contractile force during a two-hour period and completely prevented the changes in the subcellular distribution of 3H-norepinephrine. The leakage of total 3H- and decrease in the endogenous norepinephrine levels in the hearts perfused with medium containing glucose were less in comparison to the hearts perfused with substrate-free medium. The ability of tyramine to exert positive inotropic action was markedly reduced on perfusing the hearts with substrate-free medium. The data presented in this study demonstrate the effects of a substrate-free medium on cardiac norepinephrine stores; in addition these results fail to reveal any relationship between catecholamine stores and cardiac contractile force in this experimental model. © 1971, by The Williams & Wilkins Company