Localization of premotoneurons for an NMDA-induced repetitive rhythmical activity to TMNs

Abstract

The localization or characteristics of the premotoneurons for trigeminal rhythmical activity have not been clarified. We investigated the localization of premotoneurons generating an NMDA-induced repetitive rhythmical activity to trigeminal motoneurons (TMNs). The minimal circuitry for this rhythmical activity was determined using a fragmented slice preparation of the isolated brain stem from neonatal rats (0-3 days old). We recorded rhythmical neural activities from TMNs using whole and fragmented brainstem slices preparation including the trigeminal motor nucleus in the presence of the excitatory amino acid agonist NMA and the GABAA receptor antagonist, bicuculline methiodide (BIC). TMNs receive projections from premotoneurons for an NMDA-induced rhythmical activity, which can be located in the area 300 microm surrounding the trigeminal motor nucleus. NMA (20 microM) and BIC (10 microM) induced repetitive rhythmical activities on TMNs.