NMDA-induced rhythmical activity in XII nerve of isolated CNS from newborn rats.

We tried to induce rhythmical oro-facial motor activities in an isolated brain stem-spinal cord preparation from newborn rats. Neural activities were monitored from the hypoglossal nerve (XII N) and the ventral roots of the cervical cord. Bath application of N-methyl-D-aspartate (NMDA) as well as glutamate induced rhythmical burst activity in XII N distinct from and much faster than respiratory rhythm. This NMDA-induced rhythmical activity was blocked by simultaneous application of 2-amino-5-phosphonovalerate (AP5). The results demonstrate that NMDA receptor activation can induce rhythmical XII N activity different from respiration in an isolated mammalian CNS. This preparation will be useful for the investigation of neural mechanisms underlying the central generation of food ingestive movements.