Effects of chronic ethanol consumption on G proteins in brain areas associated with the nigrostriatal and mesolimbic dopamine systems

• Published in: Alcoholism, clinical and experimental research Vol. 17; no. 6; p. 1247
• Main Authors: Pellegrino, S M, Woods, J M, Druse, M J
• Format: Journal Article
• Language: English
• Published: England 01.12.1993
• Subjects: Alcoholism - genetics; Alcoholism - pathology; Animals; Blotting, Western; Calcium Channels - drug effects; Calcium Channels - physiology; Corpus Striatum - drug effects; Corpus Striatum - pathology; Dopamine - physiology; Ethanol - pharmacokinetics; GTP-Binding Proteins - genetics; Limbic System - drug effects; Limbic System - pathology; Male; Mesencephalon - drug effects; Mesencephalon - pathology; Neural Pathways - drug effects; Neural Pathways - pathology; Potassium Channels - drug effects; Potassium Channels - physiology; Rats; Rats, Inbred F344; RNA, Messenger - genetics; Substantia Nigra - drug effects; Substantia Nigra - pathology
• ISSN: 0145-6008
• DOI: 10.1111/j.1530-0277.1993.tb05237.x

This study examined the effects of chronic ethanol consumption on the content of G proteins in brain areas associated with the nigrostriatal and mesolimbic dopamine systems of male Fischer 344 rats, aged 3, 5, or 13 months at the time of killing. In addition, G protein mRNA was assessed in 3-month-old rats. G proteins were examined in ethanol-fed rats because a number of studies have implicated these proteins with both the acute and chronic effects of ethanol. Brain areas associated with the nigrostriatal and mesolimbic dopamine systems were examined because of the evidence that these systems are sensitive to ethanol. The brain areas examined include the substantia nigra (SN), striatum (ST), globus pallidus (GP), frontal cortex (FCX), nucleus accumbens (NA), ventral tegmental area (VTA), and ventral pallidum (VP). These experiments demonstrated that the 3-month-old rats that consumed a 6.6% (v/v) ethanol-containing liquid diet for 4 weeks had a significant (approximately 30-40%) increase in the mRNA content of Gi3 alpha in the FCX, VTA, and VP, and a significant (approximately 20%) decrease of that for G0 alpha in the SN. Nonetheless, the content of the G0 alpha protein subunit was not altered. In addition, there were no significant differences in the content of the proteins detected by antibodies to Gs alpha, G0 alpha, Gi1 alpha/Gi2 alpha, and G0 alpha/Gi3 alpha in the FCX, NA, and ST of similarly treated older rats (5 and 13 months). The content of mRNA for the other G proteins examined in the seven brain areas of 3-month-old rats was unaffected by chronic ethanol exposure.