Abstract
Age differences in cardiac chronotropic and inotropic responsiveness to adrenergic agonists and antagonists have been reported. These developmental differences were evaluated at the molecular level by characterizing myocardial beta adrenergic receptors in puppies(1-3 wks old) and adult mongrel dogs.
Partially purified cardiac plasma membranes (10,000-30,000xg) were obtained by differential centrifugation techniques. Beta adrenergic receptors were identified using the beta adrenergic antagonist 3H-dihydroalprenolol according to the method of Alexander et al(Proc Nat Acad Sci. 72:1546, 1975). Saturable binding sites were quantified using increasing concentrations of the labelled ligand in the presence of 10−5 M l-propranolol. Specific binding was 55% in puppies (n=20) and 80% in adult dogs (n=6). Scatchard plot analyses showed a greater number of receptors(p<0. 05) in the adult than in puppies:0. 3275±0. 0143 vs 0. 2151±0. 0105 pM/mg protein. Dissociation constant for the puppies was greater(p=0. 05) than adults: 10. 7112±1. 25 vs 4. 0224±0. 6746.
These data suggest that the maturation of adrenergic responsiveness of the myocardium may be due to developmental changes in beta adrenergic receptor affinity and number.
Article PDF
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Montgomery, S., Hepner, S. & Jose, P. 202 ONTOGENY OF CANINE CARDIAC BETA-ADRENERGIC RECEPTORS. Pediatr Res 12 (Suppl 4), 397 (1978). https://doi.org/10.1203/00006450-197804001-00207
Issue Date:
DOI: https://doi.org/10.1203/00006450-197804001-00207