Central nervous system mediated vasodepressor action of atrial natriuretic factor.
Administration of 20, 4 or 2.5 micrograms/kg of atriopeptin III (AT III) into the fourth ventricle of the brain of spontaneously hypertensive rats produced a 13, 14 and 7 mm Hg decrease in MAP respectively, while 1 microgram/kg had no effect on MAP and was significantly different from 20 or 4 micrograms/kg (p less than 0.025). In contrast, injection of AT III 20 micrograms/kg into the lateral ventricle did not produce a change in MAP. To examine an interaction of AT III with the opioidergic system, the opiate antagonist, naloxone HCl, 10 micrograms, was given by ICV injection 10 minutes prior to AT III, and significantly prevented the depressor response to AT III (p less than 0.025 compared with AT III alone). Injection of specific anti-sera to beta-endorphin failed to prevent the AT III-induced depressor response. Our results demonstrate that AT III can act within the central nervous system to decrease the MAP of rats, most likely at a locus in proximity to the fourth ventricle of the brain. Further, an interaction with the central opioidergic nervous system underlies the central effects of AT III.
Levin
E R
ER
Department of Medicine, Veterans Administration Medical Center, Long Beach, CA 90822.
Mills
S
S
Weber
M A
MA
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000494:pharmacology*; D001794:Blood Pressure / Q000187:drug effects*; D002490:Central Nervous System / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004359:Drug Therapy, Combination; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D009270:Naloxone / Q000494:pharmacology; D051381:Rats; D011918:Rats, Inbred SHR; D013997:Time Factors; D014662:Vasoconstrictor Agents / Q000378:metabolism
D014662:Vasoconstrictor Agents; D009270:Naloxone; D009320:Atrial Natriuretic Factor