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EFFECTS OF THE GABAERGIC AGENT SODIUM VALPROATE ON THE ARGININE VASOPRESSIN RESPONSES TO HYPERTONIC STIMULATION AND UPRIGHT POSTURE IN MAN
Author(s) -
CHIODERA P.,
GNUDI A.,
VOLPI R.,
MARCHESI C.,
MARCHESI M.,
DAVOLI D.,
CAPRETTI L.,
COIRO V.
Publication year - 1989
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/j.1365-2265.1989.tb00437.x
Subject(s) - vasopressin , endocrinology , medicine , arginine , orthostatic vital signs , stimulation , sodium , chemistry , osmotic concentration , gabaergic , blood pressure , inhibitory postsynaptic potential , biochemistry , organic chemistry , amino acid
SUMMARY In order to evaluate the possible influence of GABAergic neurotransmission on the arginine vasopressin (AVP) response to osmotic and pressure volumetric stimuli, the GABAergic drug sodium valproate was administered by mouth (200 or 400 mg 16 h, 8 h and just before tests) to eight normal men before osmotic (i.v. infusion of 0.51 m NaCl for 2 h) and orthostatic (standing upright and maintaining an orthostatic position for 20 min) tests. In both experimental conditions, the AVP rise was significantly lower in the presence than in absence of sodium valproate. The maximum AVP responses in the control orthostatic and osmotic tests were respectively 2.3 and 2.5 times higher than basal levels. When 600 mg sodium valproate was given, the maximum AVP rise in response to hypovolaemic and osmotic stimuli were respectively 1.75 and 2.1 times higher than basal value. Similar results were obtained giving 1.2 g sodium valproate. These results suggest that in man a GABAergic pathway is involved in the AVP responses to hypovolaemic and hyperosmotic stimuli.