Abstract
In anesthetized immobilized rats, pallidal unit activities were recorded extracellularly through glass microelectrodes. Spontaneous activities were converted to an interspike interval histogram and an autocorrelogram by a medical computer and a correlator. Following pentylenetetrazol injection (20 mg/kg i.v.), burst discharges increased remarkably and the bursts tended to synchronize with repetitive spikes in electrocorticogram. Following administration of liocaine (5 mg/kg i.v.) the bursts increased by pentylenetetrazol were facilitated in approximately 70% neurons, whereas pentobarbital showed obvious reduction of the bursts in 80% neurons, although both drugs reduced the firing rate. Facilitation of burst discharges was also observed with high doses of lidocaine alone. These results indicate that lidocaine, as compared with pentobarbital, may block more easily inhibitory rather than excitatory neurons.
