Glutamate excitation of oxytocin neurones in vitro involves predominantly non-NMDA receptors.

Experiments were undertaken to compare effects of the NMDA and non-NMDA receptor antagonists, AP5 (40 microM) and NBQX (10 microM), on glutamate-induced firing in supraoptic oxytocin (OT) and vasopressin (VP) neurones in vitro. In putative OT neurones NBQX caused a significantly greater reduction in firing than AP5, whilst in putative VP neurones both antagonists reduced activity powerfully and to a similar extent. The relatively small effect of AP5 in putative OT neurones was unaffected by the removal of extracellular magnesium. These results suggest that glutamate-induced firing in putative OT neurones is predominantly controlled by non-NMDA receptors.