Reduced cAMP levels and glycogen phosphorylase activation in isoproterenol perfused SHR myocardium

R. V. Sharma, R. C. Gupta, M. Ramanadham, R. C. Venema, R. C. Bhalla

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

The effect of isoproterenol perfusion on cAMP levels and phosphorylase activity was investigated in the spontaneously hypertensive rat (SHR) and Kyoto Wistar normotensive control rat (WKY) heart. The basal force of contraction in physiological salt solution perfused hearts was comparable between SHR and WKY. However, the force of contraction in response to 10 nM isoproterenol perfusion was decreased approximately 20-30% in SHR heart as compared to WKY heart. Basal cAMP levels were reduced in SHR hearts as compared to WKY heart. Isoproterenol perfusion resulted in an increase in cAMP levels over the basal cAMP values which was 50% and 100% in SHR and WKY hearts, respectively. Basal phosphorylase activity was higher in SHR hearts as compared to WKY hearts. However, the percentage increase in phosphorylase activity by isoproterenol perfusion over the basal values was approximately 400% in WKY hearts and only 200% in SHR hearts. The oubain-sensitive (Na+, K+)-ATPase activity, Ca2+ binding in the absence of ATP, sialic acid content, and 5′-nucleotidase activity of purified cardiac plasma membranes was not altered in SHR as compared to WKY. These results would suggest β-adrenergic mediated adenylate cyclase stimulation is decreased in SHR myocardium while other plasma membrane properties and associated enzymes may not be altered.

Original languageEnglish (US)
Pages (from-to)695-705
Number of pages11
JournalBasic Research in Cardiology
Volume78
Issue number6
DOIs
StatePublished - Nov 1 1983

Fingerprint

Glycogen Phosphorylase
Inbred SHR Rats
Isoproterenol
Myocardium
Phosphorylases
Perfusion
Cell Membrane
5'-Nucleotidase
Inbred WKY Rats
N-Acetylneuraminic Acid
Adenylyl Cyclases
Adrenergic Agents
Salts
Adenosine Triphosphate

Keywords

  • (Na, K-ATPase
  • cAMP
  • glycogen phosphorylase
  • hypertension
  • isoproterenol

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

Cite this

Reduced cAMP levels and glycogen phosphorylase activation in isoproterenol perfused SHR myocardium. / Sharma, R. V.; Gupta, R. C.; Ramanadham, M.; Venema, R. C.; Bhalla, R. C.

In: Basic Research in Cardiology, Vol. 78, No. 6, 01.11.1983, p. 695-705.

Research output: Contribution to journalArticle

Sharma, R. V. ; Gupta, R. C. ; Ramanadham, M. ; Venema, R. C. ; Bhalla, R. C. / Reduced cAMP levels and glycogen phosphorylase activation in isoproterenol perfused SHR myocardium. In: Basic Research in Cardiology. 1983 ; Vol. 78, No. 6. pp. 695-705.
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