Previous data showed the development of tolerance to a variety of pharmacological effects
of plant and synthetic cannabinoids when administered chronically. This tolerance
phenomenon has been related both to enhancement of cannabinoid metabolism and, in
particular, to down-regulation of brain CB1 cannabinoid receptors, although this has been
only demonstrated in extrapyramidal areas. In the present study, we have tested, by using
autoradiographic analysis of CB1 receptor binding combined with analysis of CB1 receptor …