DIFFERENT LEVELS OF [H-3] MK-801 BINDING IN LONG-SLEEP AND SHORT-SLEEP LINES OF MICE

The long-sleep (LS) and short-sleep (SS) lines of mice were selectivel y bred for differential sensitivity to the hypnotic effects of ethanol . Several studies suggest that excitatory amino acid receptor systems are involved in these genetically determined differences in sensitivit y to ethanol. The experiments described in this article examine furthe r the potential role of NMDA excitatory amino acid receptors in geneti cally determined differences in hypnotic sensitivity to ethanol by mea suring [H-3]MK-801 binding in eight brain regions of LS and SS lines o f mice. Significantly greater levels of binding were found in SS hippo campus and striatum. Binding levels in the remaining brain regions rev ealed no significant between-line differences. Affinity differences be tween regions were seen but no between-line differences in affinity we re found in any brain region. These findings lend support to the hypot hesis that differences in NMDA receptor systems are part of the geneti cally determined biochemistry that produces differential hypnotic sens itivity to ethanol in LS and SS mice.