Sleep disorders and the memory processing at ethanol administration

Abstract

The sleep wakefulness cycle (SWC) generally is sensitive to a variety of pharmacological and non-pharmacological impact, therefore, can be considered as valid model to study the effects of various substances, including ethanol (ET). ET,
in various doses, may change excitability of nervous circles, which are involved in regulation of sleep-wakefulness cycle
and learning and memory trace consolidation. The aim of the present study was to investigate effects of the various doses of 25% ET solution on the acquisition of the active avoidance reaction, memory trace processing and the sleep wakefulness cycle (SWC) in rats. Experiments conducted on inbred adult rats (weight 180-250 gr. N=50). The following
methods used: 1. Stereotaxic, for implantation of electrodes in the brain, oculomotor and cervical muscles; 2. Polygraph
registration of the SWC; 3. Passive avoidance test used for study of possibility of memory consolidation; 4. Active
avoidance test for study of possibility learning processes (daily 20 trials during 20 days until achievement the learning
criterion).5. Animals were injected intraperitonealy of 25% ET (1 ml/kg, 2 ml/kg, 4.5 ml/kg) solution during 20 days. 6.
The obtained date treated statistically and significance of the observed changes evaluated according to the Student’s tcriterion. Low doses of ET (0.5-1 ml/kg), facilitated elaboration of the avoidance reaction on the light compared with
control intact group (p<0.03). Middle doses (2-2.5 ml/kg) inhibited of the acquisition of the avoidance. High doses (3-4.5
ml/kg) of ET completely blocked implementation of the elaborated reaction of avoidance (p<0.03). Consolidation of
memory trace was not disturbed at administration of the low doses of ET. High doses (3-4.5 ml/kg) of ET blocked normal course of the phases and stages of SWC. The EEG wave’s amplitude noticeably depressed. Recovery of the SWC
structure observed after several days.