Chronic ethanol consumption reduces [3H]inositol (1,4,5) trisphosphate specific binding in mouse cerebellar membrane fragments

3H]In(1,4,5)P3 specific binding was determined in membrane fragments from various brain regions of adult male C57/BL mice. 3H]In(1,4,5)P3 specific binding was at least 10 times higher in cerebellum than in either striatum, cerebral cortex, hippocampus, or midbrain. Ethanol added in vitro up to 500 mM to cerebellar membrane fragments of control mice had no significant effect on 3H]In(1,4,5)P3 specific binding. In contrast, the maximal number of binding sites (Bmax) for 3H]In(1,4,5)P3 was significantly decreased in cerebella from mice which had been rendered tolerant-dependent to ethanol. KD values for these mice were unchanged when compared to control values.