Action of Mecholyl on the Respiration of Cardiac Muscle in vitro

Abstract

UNTIL now relatively little experimental evidence has been acquired about the detailed regulative function of acetylcholine (ACh) on the metabolism of cardiac muscle. Earlier investigations using the heart–lung preparation showed the oxygen-sparing effect of ACh (ref. 1). ACh seems to increase the energetic efficiency and to preserve the energy sources of the heart muscle tissue². This problem, however, has not been completely solved even by analysis of the direct action of ACh on the cardiac muscle fibre. There are only a few reports on the sparing effect of ACh in vitro. An increase of adenosine triphosphate (ATP) and glycogen content in cardiac muscle treated with ACh has been reported³. Changes in the oxygen uptake of slices treated with ACh have also been shown by some workers⁴. Recently, the application of ACh or eserine in vivo has been shown to decrease the fatty acid utilization of minced myocardial tissue⁵.