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Involvement of N ‐Methyl‐D‐Aspartic Acid Receptor Activation in Oxytocin and Vasopressin Release After Osmotic Stimuli in Rats
Author(s) -
Onaka T.,
Yagi K.
Publication year - 2001
Publication title -
journal of neuroendocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.062
H-Index - 116
eISSN - 1365-2826
pISSN - 0953-8194
DOI - 10.1111/j.1365-2826.2001.00607.x
Subject(s) - oxytocin , supraoptic nucleus , vasopressin , medicine , hypertonic saline , endocrinology , lamina terminalis , median preoptic nucleus , nmda receptor , tonicity , oxytocin receptor , chemistry , plasma osmolality , hypothalamus , receptor , biology , subfornical organ , angiotensin ii
The present study aimed to examine roles of N ‐methyl‐D‐aspartic acid (NMDA) receptors in oxytocin and vasopressin release after osmotic stimuli. A noncompetitive NMDA receptor antagonist, MK‐801 (0.2 mg/kg body weight, i.p.), significantly decreased plasma concentrations of oxytocin and vasopressin after hypertonic saline injection (0.3 or 0.6 M NaCl, i.p., 20 ml/kg). By contrast, oxytocin release induced by injection of cholecystokinin octapeptide (20 µg/kg, i.p.) was not significantly changed by MK‐801. Hypertonic saline injection increased the number of cells expressing Fos in the supraoptic nucleus and in the regions anterior and ventral to the third ventricle (AV3V) regions [the organum vasculosum of the lamina terminalis (OVLT) and median preoptic nucleus]. MK‐801 decreased the number of cells expressing protein in these areas after hypertonic saline injection. A microdialysis method showed that a hypertonic saline injection (0.6 M NaCl, 20 ml/kg, i.p.) facilitated glutamic acid release in and near the OVLT. The results support the view that NMDA receptor in the AV3V region modulates in a facilitative fashion the AV3V inputs to the supraoptic neurosecretory neurones.