title: Changes in alpha 1-adrenoceptor coupling to Ca2+ channels during development in rat heart.
abstract: It has been reported in the literature that alpha 1-adrenoceptor activation in adult rat heart does not cause an increase in Ca2+ current but involves a decrease in I(t). This may explain in part the positive inotropic effect of alpha 1-adrenoceptor activation. In this study, the effect of phenylephrine, an alpha-adrenergic agonist, on L-type Ca2+ channel current was compared in young and neonatal rat myocytes. In the presence of propranolol, phenylephrine increased the Ca2+ current (reversed by prazosin) in neonatal but not in young rat myocytes suggesting that the coupling of the alpha 1-adrenoceptor to Ca2+ channels may switch during development.
authors.affiliation: Department of Physiology, University of Alberta, Edmonton, Canada.
authors.forename: Q Y
authors.initials: QY
authors.lastname: Liu
authors.forename: E
authors.initials: E
authors.lastname: Karpinski
authors.forename: P K
authors.initials: PK
authors.lastname: Pang
mesh_terms: D000375:Aging / Q000502:physiology; D000818:Animals; D000831:Animals, Newborn; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology*; D004553:Electric Conductivity; D006321:Heart / Q000254:growth & development*; D008564:Membrane Potentials; D010656:Phenylephrine / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D011942:Receptors, Adrenergic, alpha / Q000502:physiology*; D016276:Ventricular Function
chemical_list: D015220:Calcium Channels; D011942:Receptors, Adrenergic, alpha; D010656:Phenylephrine; D011433:Propranolol; D011224:Prazosin