Effects of chronic ethanol consumption on G proteins in brain areas associated with the nigrostriatal and mesolimbic dopamine systems.
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.
Pellegrino
S M
SM
Department of Molecular and Cellular Biochemistry, Loyola University of Chicago, Stritch School of Medicine, Maywood, IL 60153.
Woods
J M
JM
Druse
M J
MJ
D000437:Alcoholism / Q000235:genetics* / Q000473:pathology; D000818:Animals; D015153:Blotting, Western; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology; D003342:Corpus Striatum / Q000187:drug effects / Q000473:pathology*; D004298:Dopamine / Q000502:physiology*; D000431:Ethanol / Q000493:pharmacokinetics; D019204:GTP-Binding Proteins / Q000235:genetics*; D008032:Limbic System / Q000187:drug effects / Q000473:pathology*; D008297:Male; D008636:Mesencephalon / Q000187:drug effects / Q000473:pathology*; D009434:Neural Pathways / Q000187:drug effects / Q000473:pathology; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics*; D051381:Rats; D011916:Rats, Inbred F344; D013378:Substantia Nigra / Q000187:drug effects / Q000473:pathology*
D015220:Calcium Channels; D015221:Potassium Channels; D012333:RNA, Messenger; D000431:Ethanol; D019204:GTP-Binding Proteins; D004298:Dopamine