Premium
Various effects of angiotensin II on amygdaloid neuronal activity in normotensive control and hypertensive transgenic [TGR(mREN‐2)27] rats
Author(s) -
Albrecht Doris,
Nitschke Thomas,
Von Bohlen Oliver,
Halbach Oliver
Publication year - 2000
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.14.7.925
Subject(s) - endocrinology , medicine , amygdala , angiotensin ii , gabaergic , bicuculline , inhibitory postsynaptic potential , chemistry , antagonist , basolateral amygdala , receptor , biology
The effects of iontophoretically ejected angiotensin II (Ang II) on the firing rate of neurons in the basolateral complex and the central and cortical amygdala were investigated in two strains of urethane anesthetized rats. In normotensive Sprague‐Dawley rats, Ang II induced a significant increase in the discharge rate of responsive amygdaloid neurons. In contrast, in the hypertensive transgenic [TGR(mREN‐2)27] rats with higher brain Ang II level, Ang II more often caused inhibitory effects on the amygdaloid firing rate in comparison with controls. The distribution of nonresponsive, excited, and inhibited neurons differed significantly in the two rat strains. Moreover, the responsiveness of amygdaloid neurons was significantly higher in transgenic rats in comparison with controls. Both the increase and the decrease in the firing rate caused by Ang II could be blocked either by angiotensin AT X or by AT 2 receptor‐specific antagonists. In many cases, the Ang II‐induced decrease in the firing rate was antagonized by bicuculline, a γ‐aminobu‐tyric acid (GABA A ) antagonist. The higher responsiveness of amygdaloid neurons in transgenic rats as well as the predominance of inhibitory effects, presumedly mediated by GABAergic interneurons, could change the output of the amygdala and its influence on thirst, kidney, and cardiovascular function or on processes of learning and anxiety.—Albrecht, D., Nitschke, T., and Von Bohlen und Halbach, O. Various effects of angio‐tensin II on amygdaloid neuronal activity in normoten‐sive control and hypertensive transgenic [TGR(mREN‐2)27] rats. FASEBJ. 14, 925–931 (2000)