Acute effect of ethanol on firing patterns of Purkinje cells in the rat cerebellar slice preparation

This study examined the acute effects of ethanol (EtOH) on the firing patte rns of Purkinje cells (PCs) using an intracellular recording in slice prepa ration of rat cerebellum. The experiments were performed in sagittal cerebe llar slices (400 mum) of adult Sprague-Dawley rats (80-100g). Ethanol was a pplied by a bath superfusion with a known concentration expressed as the pe rcentage of solution by volume (v/v) at 0.1, 0.5, 1, 2, and 4%. The result of the Chi-square test illustrated that the firing patterns were altered si gnificantly after EtOH (p = 0.007). However, the firing patterns that were altered by EtOH application were not affected by EtOH concentration (p = 0. 1296). Among the 54 PCs tested, 30 PCs did not display any spontaneous firi ng activity and 24 PCs displayed spontaneous spike activity, either spiking in the simple manner (n = 14) or cyclicly oscillating (n = 10). In the pre sence of EtOH, 31 PCs were quiet, 22 PCs exhibited simple spiking activity and 1 PC continued to oscillate. Most PCs that displayed spontaneous activi ty before EtOH application progressively slowed their spike activity after EtOH superfusion. Especially, it was evident that 9 out of 10 oscillating P Cs stopped their regular cyclic activity. In addition, 9 out of 14 PCs that displayed simple spike activity ceased to fire after EtOH application. Ele ven out of 30 quiet PCs began to fire irregularly after EtOH application an d this phenomenon usually occurred with membrane depolarization. EtOH induc ed spontaneous activity in 36.7% (11/30) of the quiescent PCs. In conclusio n, there was differential EtOH sensitivity in the vitro slice preparation. EtOH depressed the endogenously generated spontaneous activity, especially the oscillatory firing activity. In contrast, the silent PCs were excited a fter EtOH application. Since this differential sensitivity persists in the presence of tetrodotoxin (TTX), it is suggested that this differential sens itivity is peculiar to the PCs.