Spontaneous activity in the perinatal trigeminal nucleus of the rat

THE role of electrical activity in establishing appropriate connections in the trigeminal pathway remains controversial. We report here a novel observ ation of spontaneous activity in the perinatal trigeminal sensory nucleus b etween embryonic day (E) 16 to postnatal day (P) 8. Most of these spontaneo us bursts had the same polarity and were of comparable amplitude to the tri geminal nerve-evoked response. This synchronized activity was abolished by bicuculline or kynurenic acid. Recording from the teased trigeminal root du ring the spontaneous bursts also showed a corresponding afferent depolariza tion. We speculate that the GABAergic depolarization of pre- and postsynapt ic cells may contribute to the generation of the spontaneous activity and i ts propagation throughout the trigeminal sensory pathway, even in the absen ce of activity initiated from peripheral sensory receptors. (C) 1999 Lippin cott Williams & Wilkins.