Effects of voluntary ethanol consumption on emotional state and stress responsiveness in socially isolated rats

• Published in: European neuropsychopharmacology Vol. 21; no. 5; pp. 414 - 425
• Main Authors: Pisu, Maria Giuseppina, Mostallino, Maria Cristina, Dore, Riccardo, Maciocco, Elisabetta, Secci, Pietro Paolo, Serra, Mariangela
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.05.2011
• Subjects: 3α-hydroxy-5α-pregnan-20-one; Alcohol Drinking - physiopathology; Analysis of Variance; Animals; Arc; BDNF; Brain-Derived Neurotrophic Factor - metabolism; Disease Models, Animal; Dose-Response Relationship, Drug; Drinking - drug effects; Electroshock - adverse effects; Emotions - drug effects; Ethanol; Ethanol - pharmacology; GABA A receptor; Internal Medicine; Male; Maze Learning - drug effects; Pregnanolone - metabolism; Psychiatry; Rats; Rats, Sprague-Dawley; Social isolation; Social Isolation - psychology; Stress, Psychological - physiopathology; 3α-hydroxy-5α-pregnan-20-one; Arc; Ethanol; GABA A receptor; Social isolation; BDNF
• ISSN: 0924-977X; 1873-7862
• DOI: 10.1016/j.euroneuro.2010.07.006

Abstract Social isolation of rats immediately after weaning is thought to represent an animal model of anxiety-like disorders. This mildly stressful condition reduces the cerebrocortical and plasma concentrations of 3α-hydroxy-5α-pregnan-20-one (3α,5α-TH PROG) as well as increases the sensitivity of rats to the effects of acute ethanol administration on the concentrations of this neuroactive steroid. We further investigated the effects of voluntary consumption of ethanol at concentrations increasing from 2.5 to 10% over 4 weeks of isolation. Isolated rats showed a reduced ethanol preference compared with group-housed animals. Ethanol consumption did not affect the isolation-induced down-regulation of BDNF or Arc, but it attenuated the increase in the cerebrocortical concentration of 3α,5α-TH PROG induced by foot-shock stress in both isolated and group-housed animals as well as increased the percentage of number of entries made by socially isolated rats into the open arms in the elevated plus-maze test. Ethanol consumption did not affect expression of the α4 subunit of the GABAA receptor in the hippocampus of group-housed or isolated rats, whereas it up-regulated the δ subunit throughout the hippocampus under both conditions. The results suggest that low consumption of ethanol may ameliorate some negative effects of social isolation on stress sensitivity and behavior.