Role of neuropeptide Y in myocardial contractility of rats during early postnatal ontogeny.

We studied the effect of neuropeptide Y in concentrations of 10(-10)-10(-6) M on myocardial contractility of rats at the age of 7, 21, and 100 days. Studying the isometric contraction of myocardial strips showed that neuropeptide Y decreases the force of myocardial contraction in 7-day-old rat pups. Exogenous neuropeptide Y produced a biphasic effect in 21-day-old rats, which was manifested in the increase and subsequent decrease in myocardial contractility. Neuropeptide Y had little effect on myocardial contractility of 100-day-old animals.