Adrenomedullary function in the neonatal rat: responses to acute hypoxia.

摘要: The mechanism of release catecholamines from the adrenal medulla neonatal rats was examined, together with role these amines in ability organism to withstand acute O2 deprivation. Splanchnic innervation rat is non-functional until end first postnatal week. Nevertheless, hypoxia caused depletion 1-day-old as well 8-day-old animals. Pre-treatment cholinergic receptor blocking agents did not prevent catecholamine response at 1 day but older animals; results indicate that neurogenic animals proportions noradrenaline and adrenaline released by hypoxic stress also differed two ages, preferential non-neurogenic one. ontogenetic replacement adrenomedullary responses directly related onset splanchnic nerve function. Treatments which accelerated development neuronal connexions (neonatal hyperthyroidism, maternal stress) premature loss response. Prior sympathetic function, plays a predominant enabling neonate survive hypoxia. Interference invariably increased mortality during In contrast, interference neural affect hypoxia, indicating survival low PO2 conditions dependent on stage development. After functional nerves disappearance responses, became partially upon derived terminals; administration bretylium 8 days significantly compromised adrenergic function interfered PO2. At age, either phenoxybenzamine or ICI-118551, atenolol, shortened time days, only so.(ABSTRACT TRUNCATED AT 400 WORDS)