Role of Neuronal NMDA and non-NMDA Glutamate Receptors in Medial Vestibular Nucleus in the Regulation of Respiratory Rhythmogenesis in Newborn Rats In Vitro

Abstract

We studied isolated pontobulbospinal preparations from newborn rat brain. In the early postnatal period, the rostral part of the medial vestibular nucleus produces a potent inhibitory effect on neuronal structures of the bulbar respiratory center via the glutamatergic system. Microinjection of L-glutamate (50 mmol/liter) into the rostral part of the vestibular nucleus completely blocks respiratory rhythmogenesis in 0-1-day-old rat pups and reduced the frequency of generation of inspiratory discharges in 2-3-day-old rats from 8.42+/-0.68 to 2.68+/-0.32 min(-1). It was found that the leading role in the mechanism of glutamatergic modulation of the respiratory rhythmogenesis by neurons of the medial vestibular nucleus is played by NMDA and, to a lesser extent, non-NMDA glutamate receptors.