Stereospecific interaction between alcohol and opiates mediated by the mu high-affinity binding receptor

Experiment 1 revealed that preexposure to morphine blocked ethanol-induced CTA, and that conversely, preexposure to ethanol blocked morphine-induced CTA. In experiment 2, naloxazone injected 4.5 hr before the preexposure drug significantly reversed the interaction between morphine and ethanol. The results of Experiment 3 showed that preexposure to levorphanol blocked both morphine- and ethanol-induced CTAs while dextrorphan at the same dose did not affect the CTAs. These findings are discussed in terms of the involvement of the opiate receptors and their ligands in opiate-ethanol interaction.