Ethanol impairs memory by reducing the synaptic connection of the hippocampal spatial neurons

Ethanol has undesirable effects on memory and synaptic communication. However, its impact on the learned spatial memory is unclear. We investigated the damaging effects of ethanol on place neurons of rat’s hippocampal CA1. Sixty four male Wistar rats (250 g) were administered high (1-8 g/kg) or low (0.05-0.1 g/kg) doses of ethanol intraperitoneally (i.p.) and tested (10 min) for the novelty-seeking behavior using the place conditioning box. Sniffing, rearing, grooming, and compartment entering was compared between the first and the last stage, during which the animals had accessibility to the whole device. During the acquisition phase, the rats daily received ethanol (i.p.) and confined in one side of the device for 40 min. The control group solely received saline (1 ml/kg, i.p.). The achievements were analyzed by ANOVA under α = 0.05. The ethanol-acquired animals with the high doses did not recall the information of the familiarization day and displayed a high tendency toward the non-confined side of the box. The rats also showed a reduction in place neuron synaptic strands. Ethanol disrupts spatial memory and also diminishes CA1 place neuron’s fibers.