ENDOGENOUS CODEINE AND MORPHINE ARE STORED IN SPECIFIC BRAIN NEURONS

Codeine and morphine have been detected in mammalian brain by radioimm unoassay (RIA), and in brain and other tissues by gas-chromatography/m ass-spectrometry (GCMS) in different laboratories5.3. It has been also shown that rat liver can synthesize the skeleton of the morphine mole cule18, thus suggesting that this alkaloid, which is the prototype of mu-receptor agonists, plays a physiological role in brain. We report t he presence of morphine-like immunoreactive compounds inside the cell body, fibers and terminals of neurons in different brain areas. Moreov er, neurons localized in the same brain areas were capable of accumula ting and storing [H-3]morphine slowly infused intracerebroventricularl y (i.cv.) through an osmotic minipump.