Title

Protein kinase regulation of cardiac phosphorylase activity and contractility

UMMS Affiliation

Department of Physiology

Date

5-1978

Document Type

Article

Subjects

Animals; Cyclic AMP; Epinephrine; Male; *Myocardial Contraction; Myocardium; Phosphorylase Kinase; Phosphorylases; Practolol; Protein Kinases; Rats

Disciplines

Cardiovascular Diseases | Physiology

Abstract

The relationship between cAMP-dependent protein kinase activity and epinephrine-produced activation of phosphorylase and increase in contractility was investigated in the intact working rat heart. Epinephrine was administered as a bolus into the superior vena cava of open-chest preparations and the hearts were rapidly frozen. cAMP increased within 5 s and returned to control within 20-30 s. Protein kinase and phosphorylase kinase activity ratios increased transiently with the same time course as that for cAMP. The phosphorylase activity ratio and the rate of left ventricular pressure development increased maximally within 15 s and returned to control in 30-60 s. Continuous infusion of epinephrine caused a sustained elevation of the protein kinase. Free catalytic protein kinase activity increased proportionately with the dose of epinephrine. The beta-adrenergic blocking agent, practolol, had no effect on the basal levels of the five parameters studied, but did prevent the epinephrine-produced increases. The results suggest that the time course of cAMP-dependent protein kinase activation is appropriate if this enzyme is to play a role in the catecholamine-induced increase in both glycogenolysis and contractility in the in vivo heart.

Rights and Permissions

Citation: Am J Physiol. 1978 May;234(5):H638-45.

Related Resources

Link to article in PubMed

PubMed ID

206158