Relations between muscimol, quinuclidinyl benzilate and nicotine binding sites in brain after very long treatment with ethanol in rats

Abstract

Rats were treated with ethanol in the drinking fluid 2 × 1 h daily for 83 weeks. [ 3H]Muscimol, [ 3H]quinuclidinyl benzilate ([ 3H]QNB) and [ 3H]nicotine binding was measured in selected brain areas 7, 14 and 21 days after withdrawal of ethanol. A significant increase (P < 0.05) when compared to controls was found on day 7 in both [ 3H]-QNB binding in the cortex and high affinity [ 3H]muscimol binding in the cerebellum. Furthermore, on day 7 of abstinence there was a positive correlation in number of binding sites between [ 3H]muscimol (high affinity sites; cerebellum) and [ 3H]QNB (cortex) while a negative correlation was found between [ 3H]muscimol (low affinity sites; cerebellum) and [ 3H]nicotine (cortex). The first correlation might indicate a relation between increased excitation (QNB) and increased inhibition (muscimol) in two brain areas.