Title

Lack of oscillations in cyclic AMP, cAMP-protein kinase and glycogen phosphorylase during the cardiac cycle in perfused rat hearts

UMMS Affiliation

Department of Physiology

Date

5-1992

Document Type

Article

Subjects

Animals; Cyclic AMP; Diastole; Male; Myocardial Contraction; Myocardium; Perfusion; Phosphorylases; Protein Kinases; Rats; Rats, Inbred Strains; Systole

Disciplines

Cardiovascular Diseases | Cellular and Molecular Physiology | Physiology

Abstract

It is unclear whether reported fluctuations in the level of adenosine 3',5'-cyclic monophosphate (cAMP) during a single cardiac cycle in ventricular muscle are associated with distal changes in cAMP-dependent processes. The degree of cAMP variation and its effect, if any, on biochemical sequelae during the cardiac cycle, were investigated by determining the level of cAMP and the activity ratios of cAMP-dependent protein kinase and glycogen phosphorylase in the rat ventricular myocardium. Isolated perfused hearts contracting at 240 beats/min and free of exogenously administered catecholamines were freeze-clamped, utilizing an automated clamping device capable of freezing the entire heart in less than 50 ms. The cardiac cycle was segmented into phases utilizing three different segmentation schemes. No significant difference was detected between phases regardless of the method of segmentation for cAMP, cAMP-dependent protein kinase, or glycogen phosphorylase levels. These results suggest that the levels of cAMP and the activities of cAMP-dependent protein kinase and glycogen phosphorylase do not vary significantly during a single cardiac cycle in the mammalian myocardium.

Rights and Permissions

Citation: J Mol Cell Cardiol. 1992 May;24(5):477-84.

Related Resources

Link to article in PubMed

PubMed ID

1321913