Ethanol preference is inversely correlated with ethanol-induced dopamine release in 2 substrains of C57BL/6 mice.
BACKGROUND
The C57BL/6 mouse model has been used extensively in alcohol drinking studies, yet significant differences in ethanol preference between substrains exist. Differences in ethanol-induced dopamine release in the ventral striatum could contribute to this variability in drinking behavior as dopamine has been implicated in the reinforcing properties of ethanol.


METHODS
A 2-bottle choice experiment investigated the difference in ethanol preference between C57BL/6J and C57BL/6NCrl animals. Microdialysis was used to determine dopamine release and ethanol clearance in these 2 substrains after intraperitoneal injections of 1.0, 2.0 and 3.0 g/kg ethanol or saline.


RESULTS
C57BL/6J mice exhibited significantly greater ethanol preference and less ethanol-stimulated dopamine release compared with C57BL/6NCrl mice. The intraperitoneal injections of ethanol caused a significant increase in dopamine in both substrains at all 3 doses with significant differences between substrains at the 2 highest alcohol doses. Saline injections had a significant effect on dopamine release when given in a volume equivalent to the 3 g/kg ethanol dose. Ethanol pharmacokinetics were similar in the 2 substrains at all 3 doses.


CONCLUSIONS
Ethanol-induced dopamine release in the ventral striatum may contribute to the differences in alcohol preference between C57BL/6J and C57BL/6NCrl mice.
Ramachandra
Vorani
V
University of Texas at Austin, Pharmacology-PHAR, Austin, Texas 78712, USA.
Phuc
Steven
S
Franco
Ana Crystal
AC
Gonzales
Rueben A
RA
D000428:Alcohol Drinking / Q000503:physiopathology; D000818:Animals; D001479:Basal Ganglia / Q000187:drug effects / Q000378:metabolism; D001522:Behavior, Animal / Q000187:drug effects* / Q000502:physiology; D002492:Central Nervous System Depressants / Q000494:pharmacology*; D004298:Dopamine / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D000431:Ethanol / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL
D002492:Central Nervous System Depressants; D000431:Ethanol; D004298:Dopamine