Effects of vasopressin and involvement of receptor subtypes in the rat central amygdaloid nucleus in vitro.
Effects of arginine-vasopressin (AVP) on neurons in the central amygdaloid nucleus (ACe) were investigated with rat brain slice preparations using extracellular recording methods. Of 160 ACe neurons tested, 70 cells (44%) were excited and 9 cells (6%) were inhibited by bath application of AVP at 3 x 10(-7) M. The excitatory effects of AVP were dose-dependent and the threshold concentration was approximately 10(-10) to 10(-9) M. The excitatory effects of AVP persisted under blockade of synaptic transmission by perfusing with Ca2+-free and high-Mg2+ medium, whereas the inhibitory effects were abolished by synaptic blockade. AVP-induced effects were mimicked by a V1-receptor agonist and completely blocked by a selective V1-antagonist. V2-agonist produced no effects on ACe neurons and V2-antagonist had no effect on AVP-induced excitation. These results showed that the excitatory effect of AVP on ACe neurons was produced by a direct action through the V1-receptors, whereas the inhibitory response of ACe neurons to AVP seemed to be produced by an indirect action. The results of this study suggest that AVP is involved in the amygdala-relevant functions as a neurotransmitter or a neuromodulator.
Lu
Y F
YF
The First Department of Physiology, Okayama University Medical School, Japan. yunfeilu@med.okayama-u.ac.jp
Moriwaki
A
A
Tomizawa
K
K
Onuma
H
H
Cai
X H
XH
Matsui
H
H
D000679:Amygdala / Q000166:cytology / Q000187:drug effects*; D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology*; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D008297:Male; D009474:Neurons / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D009435:Synaptic Transmission / Q000187:drug effects
D001127:Arginine Vasopressin