Changes in alpha 1-adrenoceptor coupling to Ca2+ channels during development in rat heart.
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.
Liu
Q Y
QY
Department of Physiology, University of Alberta, Edmonton, Canada.
Karpinski
E
E
Pang
P K
PK
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
D015220:Calcium Channels; D011942:Receptors, Adrenergic, alpha; D010656:Phenylephrine; D011433:Propranolol; D011224:Prazosin