Physical conditioning and membrane receptors for cardioregulatory hormones.

Published

Journal Article

To seek possible mechanisms for the relative bradycardia induced by physical conditioning we studied the effects of an eight-week swimming programme upon cardiac beta-adrenergic and muscarinic-cholinergic receptors in rats. A training effect was documented by an increase in the ratio of heart wet weight to body weight in the conditioned animals compared with sedentary controls. Cardiac beta-adrenergic receptors as assessed in crude membrane fractions by the binding of (-) (3H) dihydroalprenolol did not differ significantly in either number or affinity in conditioned hearts (30 +/- 2 fmol.mg-1 protein; KD = 1.4 +/- 0.1 nmol.litre-1) compared with sedentary hearts (33 +/- 2 fmol.mg-1; KD = 1.5 +/- 2 nmol.litre-1). Likewise cardiac muscarinic-cholinergic receptors as assessed by the binding of (3H) quinuclidinyl benzilate to crude cardiac membranes did not differ significantly in either number or affinity in conditioned hearts (116 +/- 6 fmol.mg-1 protein; KD = 0.17 +/- 0.03 nmol.litre-1) compared with sedentary hearts (125 +/- 11 fmol.mg-1; KD = 0.19 +/- 0.03 nmol.litre-1). We conclude that the bradycardia of physical training is probably mediated by mechanisms other than alterations in cardiac beta-adrenergic or muscarinic-cholinergic receptors.

Full Text

Duke Authors

Cited Authors

  • Williams, RS

Published Date

  • March 1, 1980

Published In

Volume / Issue

  • 14 / 3

Start / End Page

  • 177 - 182

PubMed ID

  • 6249497

Pubmed Central ID

  • 6249497

Electronic International Standard Serial Number (EISSN)

  • 1755-3245

International Standard Serial Number (ISSN)

  • 0008-6363

Digital Object Identifier (DOI)

  • 10.1093/cvr/14.3.177

Language

  • eng