[Effects of angiotensin II, atrial natriuretic peptide III and arginine vasopressin on activity of paraventricular neurons of rat hypothalamic slices].
The effects of angiotensin II (AG II), atrial natriuretic peptide III (ANP III) and arginine vasopressin on 101 paraventricular nucleus (PVN) neurons from 28 brain slices of rats were observed. After perfusing the brain slices with AG II (10(-7) mol/L, 3 min), spontaneous discharge rate of 28/50 (56.0%) neurons was significantly increased, while that of 5/50 (10.0%) was significantly decreased and 17/50 (34.0%) neurons were non-responsive. Both of excitatory and inhibitory effects of AG II on neurons in PVN were completely blocked by AG II receptor blocker saralasin (10(-6) mol/L). As the brain slices were perfused with ANP III (10(-7) mol/L, 3 min), the firing rate of 16/26 (61.54%) neurons was decreased, while that of 1/26 (3.85%) neurons was increased and 9/26 (34.61%) neurons were non-responsive. During perfusing brain slices with AVP (10(-7) mol/L, 3 min), the firing rate of 19/25 (76.0%) neurons was significantly increased, while that of 1/25 (4.0%) neurons was decreased and 5/25 (20.0%) neurons were non-responsive. Twenty-five PVN neurons were successively perfused with three peptides. Among them, 4 were excited by both AG II and AVP, 2 were excited by AG II and inhibited by ANP III, and 7 were excited by AVP and inhibited by ANP III. The results show that the discharge rate of PVN neurons may be affected by AG II, ANP III and AVP. It is likely that PVN acts as an integrative site for neuroendocrine and autonomic functions.
Yang
L M
LM
Department of Physiology, Institute of Basic Medicine, Hebei Medical College, Shijazhuang.
Wang
Z A
ZA
Ho
S Y
SY
D000804:Angiotensin II / Q000502:physiology*; D000818:Animals; D001127:Arginine Vasopressin / Q000502:physiology*; D009320:Atrial Natriuretic Factor / Q000502:physiology*; D004594:Electrophysiology; D005260:Female; D008297:Male; D009474:Neurons / Q000502:physiology; D010286:Paraventricular Hypothalamic Nucleus / Q000502:physiology*; D010446:Peptide Fragments; D051381:Rats; D017207:Rats, Sprague-Dawley; D012504:Saralasin / Q000494:pharmacology
D010446:Peptide Fragments; D000804:Angiotensin II; D001127:Arginine Vasopressin; C062525:atrial natriuretic factor prohormone (103-126); D009320:Atrial Natriuretic Factor; D012504:Saralasin