Age-related functional effects linked to phosphatase activity in ventricular myocytes

Elizabeth M. Grey, Chun K. Chan, Yi Chen, Polly Hofmann

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Conflicting reports exist regarding the influence of β-adrenergic stimulation on the maximum velocity of shortening (V max ) in ventricular myocytes. This may be due to an unrecognized effect of maturation. In the present study, the effects of β-adrenergic receptor stimulation on myocytes from hearts of juvenile nonbred and young adult retired breeder female rats were compared. Ventricular myocytes from young adults had a β-adrenergic-dependent increase in V max and Ca 2+ -dependent actomyosin ATPase that was not observed in myocytes from juveniles. Myocytes from young adults had both an increase in β-myosin heavy chain (MHC) and higher basal serine/threonine phosphatase activity compared with juvenile rats. Additional studies established moderate increases in β-MHC induced by hypothyroidism do not confer myocardial β-adrenergic responsiveness, whereas inhibition of the higher phosphatase activity in myocytes from young adults blocks the age-dependent, β-adrenergic-induced increase in cross-bridge cycling rates. We propose that the higher phosphatase activity of myocytes from young adults compared with juveniles allows for a greater functional response of the myocardium to β-adrenergic stimulation.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume285
Issue number1 54-1
StatePublished - Jul 1 2003

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Phosphoric Monoester Hydrolases
Muscle Cells
Adrenergic Agents
Young Adult
Myosin Heavy Chains
Phosphoprotein Phosphatases
Myosins
Hypothyroidism
Adrenergic Receptors
Myocardium

All Science Journal Classification (ASJC) codes

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

Cite this

Age-related functional effects linked to phosphatase activity in ventricular myocytes. / Grey, Elizabeth M.; Chan, Chun K.; Chen, Yi; Hofmann, Polly.

In: American Journal of Physiology - Heart and Circulatory Physiology, Vol. 285, No. 1 54-1, 01.07.2003.

Research output: Contribution to journalArticle

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