THE EFFECT OF ETHANOL ON THE ACTIVITY OF HIPPOCAMPAL NEURONS
Malkov A.E., Teplova V.V.
Institute of theoretical and experimental biophysics RAS, Pushchino, Moscow region, Russia
Excessive consumption ofalcoholcauses the developmentof some seriousdiseases, including brain damagefrom mildcognitive impairmenttoexpressalcoholicencephalopathy.Research on the effectsof alcoholon cognitiveactivity of man andexperimental animalsrevealed aviolation of spatialmemory and attentionin the development ofhepatic encephalopathy.
However, the mechanismsof the hippocampus damage,the brain structureresponsible formemory formation,remain unknown. The effect of acute and chronic alcohol intoxication on the activity of hippocampal neurons in vivo and the excitability of neurons in brain slices was studied. It was found that, in animals with acute alcohol intoxication, an abrupt enhancement of rhythmic processes in the hippocampus occurs, indicating the impairment of the processing of stimuli from hippocampal sensory and neocortical inputs and the loss of the ability to adequately process the information. It was shown that, the intensity of hippocampal oscillations in rats with chronic alcohol intoxication significantly decreases even after one month of alcohol intake, which indicates the impairment of the cognitive function of the hippocampus. In chronic alcoholic rats, the electrical and sensory stimulation caused a depression of the hippocampal activity. On hippocampal slices of rat subjected to acute and chronic alcohol intoxication, evidence for the changes in both background and stimulation-induced activity of CA1 field pyramidal neurons was obtained. In addition, changes in the excitability threshold after the application of glutamate and picrotoxin were observed. In the neuronal activity of rats with acute alcohol intoxication, no significant differences from the control were observed. In the hippocampus of rats with chronic alcohol intoxication, a decrease in the frequency of volley discharges of neurons and an increase in the latent period of responses to electrical stimulation were observed. It was found that brain neurons of alcoholic rats are more strongly activated by the action of glutamate. In all alcohol intoxication models, glutamate increased the latent period. The data obtained indicate that, during the development of chronic alcohol intoxication, morphofunctional changes occur in the hippocampus, which lead to a decrease in the excitability of this structure and the impairment of the ability to adequately respond to external stimuli.ThisworkwassupportedbyRFBRgrant№ 11-04-01798-a.