Relative efficacy of the opioid antagonist, naltrexone, on the initiation and promotion phases of rat mammary carcinogenesis. Inhibition of morphine tolerance and dependence by diazepam and its relation to m-opioid receptors in the rat brain and spinal cord. Naltrexone administration decreases ad libitum smoking behavior. The effect of chronic administration of nicotine on antinociception, opioid receptor binding and met-enkephalin levels in rats. The effect of GM1 gangliosides.
Glutamate receptors participate in the nicotine-induced change of met enkephalin in striatum.