[The effect of stimulation of the adrenergic receptors on the frequency depression of the temporal parameters of the action potential in the right atrium of rats].
At a stimulation rate of 1 Hz, activation of alpha-adrenoreceptors prolonged the AP duration at 10%, 50%, and 90% repolarisation at 10(-7), 10(-6) M in the rat isolated right atria, but shortened it at a higher concentration of 10(-5) M. The frequency-induced depression of the AP duration became more evident in cardiomyocytes stimulated by 10(-7), 10(-6) M and less obvious at 10(-5) M of alpha-adrenoagonist. Activation of alpha-adrenoreceptors by isoprenalin shortened the AP duration and enhanced the stimulation-rate-dependent changes in the atrial AP configuration.
Petrashevskaia
N N
NN
Belorussian State University, Minsk, Belorussia.
Malykhina
A P
AP
Sidorov
A V
AV
Lobanok
L M
LM
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000818:Animals; D016275:Atrial Function; D004305:Dose-Response Relationship, Drug; D006321:Heart / Q000187:drug effects* / Q000502:physiology; D006325:Heart Atria / Q000166:cytology / Q000187:drug effects; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D008839:Microelectrodes; D009206:Myocardium / Q000166:cytology*; D010656:Phenylephrine / Q000494:pharmacology; D051381:Rats; D011941:Receptors, Adrenergic / Q000187:drug effects* / Q000502:physiology; D013268:Stimulation, Chemical; D013997:Time Factors
D000316:Adrenergic alpha-Agonists; D000318:Adrenergic beta-Agonists; D011941:Receptors, Adrenergic; D010656:Phenylephrine; D007545:Isoproterenol