关键词:
Anteroventral third ventricular
region (AV3V)
Antidiuretic hormone
Gamma aminobutyric acid
Hyperosmolality
Hypovolemia
Neurosteroid
摘要:
Anteroventral third ventricular region (AV3V) that regulates autonomic functions through a GABAergic mechanism possesses neuroactive steroid (NS)-synthesizing ability. Although NS can exert effects by acting on a certain type of GABA(A)-receptor (R), it is not clear whether NS may operate to modulate AV3V GABAergic activity for controlling autonomic functions. This study aimed to investigate the issue. AV3V infusion with a GABA(A) antagonist bicuculline increased plasma vasopressin (AVP), glucose, blood pressure (BP), and heart rate in rats. These events were abolished by preinjecting its agonist muscimol, whereas the infusion with allopregnanolone, a NS capable of potentiating GABA(A)-R function, affected none of the variables in the absence or presence of such bicuculline actions. Similarly, AV3V infusion with pregnanolone sulfate, a NS capable of antagonizing GABA(A)-R, produced no effect on those variables. AV3V infusion with muscimol was effective in inhibiting the responses of plasma AVP or glucose, or BP to an osmotic loading or bleeding. However, AV3V infusion with aminoglutethimide, a NS synthesis inhibitor, did not affect any of the variables in the absence or presence of those stimuli. These results suggest that NS may not cause acute effects on the AV3V GABAergic mechanism involved in regulating AVP release and other autonomic function. (C) 2015 Elsevier Ireland Ltd and the Japan Neuroscience Society. All rights reserved.