Abstract: Objective To observe the changes of adenylate cyclase(AC) on cerebral regions related to morphine dependence in rats and investigate the relationship between the enzymological changes and the mechanism of morphine dependence. Methods The technique of enzyme-histochemistry was used to detect the variations of AC of special seven cerebral regions including frontalis cortex, lenticula, corpus amygdaloideun, substantia nigra, hippocampus, periaqueductal gray and locus coerleus in morphine dependent rats. The enzymological changes were observed by optical microscope. Changes of gray degree of these cerebral regions were also observed by using the image analysis system. Results Compared with those in control group, the contents of AC in morphine dependent groups were increased. Conclusion The contents of AC are increase in those regions. The mechanism of morphine dependence close related to the increasing of AC. The correlation of the mechanism of morphine dependence and up-regulation of AC/cAMP-PKA system is discussed.

Key words: morphine-dependence, cerebral regions related to morphine-dependence, adenylate cyclase