RESUMO
We studied the effect of adrenoreceptor stimulation on the frequency of spontaneous activity and amplitude-time parameters of isometric contraction of the atrial myocardial strips from newborn rats, as well as the effect of Y receptor stimulation against the background of adrenoreceptor activation. After addition of Y1,5 receptor agonist [Leu31, Pro34] NPY (10-7 M), a tendency to a decrease in the effect of ß1,2-adrenoreceptor agonist isoproterenol (10-5 M) on the frequency of spontaneous activity and atrial myocardial contractility was observed. The age-related features of the effect of NPY on the frequency of spontaneous activity and contractility of myocardial strips from newborn and adult rats were revealed.
Assuntos
Neuropeptídeo Y , Receptores de Neuropeptídeo Y , Ratos , Animais , Neuropeptídeo Y/farmacologia , Receptores de Neuropeptídeo Y/agonistas , Animais Recém-NascidosRESUMO
We studied combined effect of the ß1,2-adrenoreceptor agonist isoproterenol and the Y1,5 receptor agonist [Leu31, Pro34]neuropeptide Y on the frequency of spontaneous activity and myocardial contractility in 21- and 100-day-old rats. Isoproterenol increased the frequency of spontaneous activity and reduced the main parameters of isometric contraction of the atrial myocardium. When [Leu31, Pro34]neuropeptide Y was added, the frequency of spontaneous activity and the negative inotropic and the positive chronotropic effects of isoproterenol were reduced in 100-day-old rats. In 21-day-olds rats, a tendency to a decrease in the effect of isoproterenol was observed.
Assuntos
Fibrilação Atrial , Neuropeptídeo Y , Ratos , Animais , Neuropeptídeo Y/farmacologia , Receptores de Neuropeptídeo Y/agonistas , Receptores de Neuropeptídeo Y/fisiologia , Adrenérgicos/farmacologia , Isoproterenol/farmacologiaRESUMO
The effects of neuropeptide Y (10-9-10-6 M) on electrical activity of right atrial cardiomyocytes of rats aging 7, 21, and 100 days were examined in vitro. Neuropeptide Y affected the amplitude-temporal parameters of the action potential in these cells. It decreased the duration of repolarization phase in 7-day-old rats in concentrations of 10-8 and 10-7 M, in 21-day-old rats at 10-8 and 10-6 M, and in 100-day-old at 10-6 M. The data indicate elevation of total membrane potassium current under the action of neuropeptide Y.
Assuntos
Potenciais de Ação/efeitos dos fármacos , Átrios do Coração/efeitos dos fármacos , Átrios do Coração/crescimento & desenvolvimento , Miócitos Cardíacos/efeitos dos fármacos , Neuropeptídeo Y/farmacologia , Envelhecimento/efeitos dos fármacos , Envelhecimento/fisiologia , Animais , Animais Recém-Nascidos , Células Cultivadas , Átrios do Coração/citologia , Potenciais da Membrana/efeitos dos fármacos , Contração Miocárdica/efeitos dos fármacos , Miócitos Cardíacos/fisiologia , RatosRESUMO
We studied the effect of neuropeptide Y in concentrations of 10-8-10-6 M on electrical activity of adult rat right atrial cardiomyocytes with preserved spontaneous activity. Neuropeptide Y was found to modulate the amplitude-time parameters of action potential: in concentrations of 10-7 and 10-6 M it reduced the membrane potential, increased the amplitude of action potential and duration of the repolarization phase, and reduced the frequency of action potential generation. In concentration of 10-6 M, neuropeptide Y produced stronger effect on the analyzed parameters, while in concentration of 10-8 M it produced no significant changes.