Effects of sympathetic activation on plasma renin activity in the developing rat.
The present experiments studied the ontogeny of sympathetic control of the renin-angiotensin system by using pharmacological agents, which act at different levels of the sympathetic axis, to increase plasma renin activity (PRA) during the preweanling period in Sprague-Dawley rats. The selective beta-1 adrenoceptor agonist, prenalterol, produced age- and dose-dependent PRA increases. In 5- and 10-day-old animals, prenalterol treatment produced minimal stimulation of PRA and the dose-response curve was essentially flat. In contrast, greater PRA responses to increasing doses of prenalterol were found in 15- and 20-day-old animals. The PRA response to tyramine, which causes norepinephrine release from postganglionic sympathetic fibers, gradually increased between 5 and 20 postnatal days of age, first producing significant stimulation on day 15. Centrally mediated sympathetic activation with yohimbine also produced age-dependent stimulation of PRA that was comparable to the increases produced by tyramine between postnatal days 10 and 20. However, in contrast to tyramine, yohimbine produced a significant increase in PRA on postnatal day 5. The present results suggest that functional sympathetic control of the renin-angiotensin system matures during the second to third postnatal week in the Sprague-Dawley rat, and this may be related to the development of beta-1 adrenoceptors in the kidney that regulate renin release.
Department of Psychology, University of Iowa, Iowa City.
R F
RF
Kirby
A K
AK
Johnson
D000367:Age Factors; D000818:Animals; D001262:Atenolol / Q000494:pharmacology; D005260:Female; D008297:Male; D011294:Prenalterol / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012083:Renin / Q000097:blood*; D013564:Sympathetic Nervous System / Q000502:physiology*; D014439:Tyramine / Q000494:pharmacology; D015016:Yohimbine / Q000494:pharmacology
D015016:Yohimbine; D001262:Atenolol; D012083:Renin; D011294:Prenalterol; D014439:Tyramine