Accession Number : AD0261440

Title :   THE ACTION OF DRUGS ON FUNCTION AND PHOSPHORYLASE ACTIVITY OF THE PERFUSED RAT HEART

Corporate Author : PENNSYLVANIA UNIV PHILADELPHIA

Personal Author(s) : HAUGAARD,NIELS

Report Date : 10 JUL 1961

Pagination or Media Count : 1

Abstract : Studies on the action of drugs on heart function and phosphorylase activi y re b i g continued. In studies with the open-chest rat preparation, simultaneous measurements were made of blood pressure, rate and force of contraction and electrical activity of the heart. At the end of a period of observation, the hear was rapidly removed for phosphorylase determination. With this preparation, i is po sible to stu y heart function under conditions closer to those existing in vivo than with the perfused heart. The level of phosphorylase a, under control conditions, is much higher than in the heart perfused with Locke solution (40% compared to 10 to 15% of total phosphorylase). In experiments with open-chest rats, the following were establish d: (1) ganglion stimulating drugs such as dimethylph nylpiperazinium (DMPP) hich release stored tissue catecholamines stimulate the heart and increase the activity of phosphorylase a, (2) injection of acetylcholine in doses sufficient to produce marke bradycardia causes a significant decrease in enzyme activity, and (3) depr ssion of he rt produced by stimul tion of the vagus nerve decreases phosphorylas ctivity. (Author)

Descriptors :   *DRUGS, *PHOSPHORYLASES, BLOOD CIRCULATION, ENZYMES, HEART, LABORATORY ANIMALS, PHYSIOLOGY

Distribution Statement : APPROVED FOR PUBLIC RELEASE