Opioid system of the brain and ethanol.
Influence of blocking of opioid receptors with concomitant intraperitoneal injections of Naloxone (20 mg/kg) (non-selective antagonist of opioid system) on the outcomes of anesthetic dose of ethanol (4,25 ml /kg 25% solution) was investigated in the rats. The sleep-wakefulness cycle (SWC) was used as a model for identification of the effects. Alterations of the SWC structure adequately reflect the neuro-chemical changes, which may develop during pharmacological and non-pharmacological impact. Administration of anesthetic dose of ethanol evoked considerable modification of spontaneous EEG activity of the neocortex. The EEG activity was depressed and full inhibition of spinal reflexes and somatic muscular relaxation did occur. During EEG depression regular SWC did not develop. All phases of SWC were reduced. The disturbances of SWC, such as decrease of slow wave sleep and paradoxical sleep duration and increase of wakefulness, remained for several days. At concomitant administration of Naloxone and ethanol, duration of EEG depression decreased significantly. Generation of normal SWC was observed on the same experimental day. However, it should be noted that complete abolishment of ethanol effects by Naloxone was not observed. The results obtained suggest that Naloxone partially blocks ethanol depressogenic effects and duration of this effect is mediated by GABA-ergic system of the brain.
I. Beritashvili Institute of Physiology, Tbilisi, Georgia.
M
M
Gogichadze
M
M
Mgaloblishvili-Nemsadze
N
N
Oniani
N
N
Emukhvary
T
T
Basishvili
D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000503:physiopathology; D004569:Electroencephalography; D000431:Ethanol / Q000633:toxicity*; D009270:Naloxone / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D011957:Receptors, Opioid / Q000502:physiology*; D012890:Sleep / Q000187:drug effects*; D014851:Wakefulness / Q000187:drug effects*
D009292:Narcotic Antagonists; D011957:Receptors, Opioid; D009270:Naloxone; D000431:Ethanol