Abstract
Genetic regulation of acute tolerance to ethanol may be associated with ethanol consumption and other ethanol-related behaviors in rodents. We have used lines of mice, selectively bred for high and low acute functional tolerance (HAFT and LAFT, respectively) to ethanol-induced loss of balance to test this hypothesis. Replicate HAFT and LAFT lines differ in AFT to ethanol-induced loss of balance by 4.4- and 5-fold, respectively. Frequency distributions and mean AFT scores for those lines, F1, and backcrosses show a dominance for the HAFT phenotype. Time courses for acquisition and decay showed that AFT to ethanol-induced loss of balance developed rapidly, could be maintained up to 6 h with repeated doses, and decayed 6 h after peak tolerance and discontinuance of ethanol administration. The lines did not differ in initial sensitivity as measured by brain ethanol concentration at loss of balance, indicating that initial sensitivity and AFT to loss of balance were not coselected traits. Surprisingly, HAFT versus LAFT lines did not differ in development of AFT to loss of righting response, or hypothermia, indicating different mechanisms or neuronal systems mediate genetic influences on these measures. Voluntary ethanol consumption was low in both of the replicate lines, but HAFT lines consumed greater amounts of ethanol than LAFT lines. The HAFT and LAFT lines developed AFT to pentobarbital-induced loss of balance, however, there were no line differences in rates or extent of the AFT development. These results show that genetic regulation of AFT development is drug- as well as response-specific.
Footnotes
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Send reprint requests to: V. Gene Erwin, School of Pharmacy, University of Colorado Health Science Center, Box C238, 4200 East 9th Ave., Denver, CO 80262. E-mail:Gene.Erwin{at}UCHSC.edu
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↵1 This work was supported, in part, by U.S. Public Health Service Grants AA 03527, AA00093, and AA 07330.
- Abbreviations:
- AFT
- acute functional tolerance
- NP
- nonpreferring
- HAFT
- high acute functional tolerance
- LAFT
- low acute functional tolerance
- RI
- recombinant inbred
- BEC
- blood ethanol concentration
- BrECLB
- brain ethanol concentration at loss of balance
- CAFT
- control acute functional tolerance
- VEC
- voluntary ethanol consumption
- Received August 13, 1999.
- Accepted January 7, 2000.
- The American Society for Pharmacology and Experimental Therapeutics
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