Audiogenic seizures potentiate hippocampal neuronal loss in ethanol-dependent rats

Abstract

Objective: Audiogenic seizure (AS) susceptibility is observed following withdrawal from chronic ethanol treatment in rodents. This is the first study to investigate and compare the effects of ethanol withdrawal on the hippocampal formation in AS appeared and nonappeared animals. Material and Methods: Adult male Wistar rats (225-320 g) were used. Ethanol was given to rats in a modified liquid diet for twenty days. Daily ethanol consumption was in a range of 10.35 +/- 1.25 to 15.20 +/- 0.79 g/kg during the exposure to ethanol (7.2%). At the end of exposure to a 7.2% ethanol-containing liquid diet, ethanol was withdrawn and withdrawal signs were recorded or rated. Increased stereotyped behavior, wet dog shakes, agitation, tail-stiffness and abnormal posture and gait appeared during ethanol withdrawal in dependent rats. AS was also induced in 5 of 11 of ethanol dependent rats. Following audiogenic stimuli, rats were decapitated and their brains were removed. Neuron counts from pyramidal cell layers in CA1 and CA2-3 regions of the hippocampus were obtained from control rats and ethanoldependent rats with and without audiogenic seizure. Results: Significant neuronal losses were found in CA1 and CA2-3 regions of the hippocampal formation in the ethanol-dependent group. Neuronal loses in AS appeared group were significantly more than in AS non-appeared group. Conclusions: ASs during ethanol withdrawal significantly potentiated neuronal degeneration in all subdivisions of the CA area of the hippocampal formation in rats. Thus, prevention of seizures in alcoholic individuals may be important for protection from excessive neuronal damage in the hippocampus.