BEHAVIORAL CONSEQUENCES OF MATERNAL EXPOSURE TO NATURAL CANNABINOIDS IN RATS

Cannabis sativa preparations (hashish, marijuana) are the most widely used illicit drugs during pregnancy in Western countries. The possible long-term consequences for the child of in utero exposure to cannabis derivatives are still poorly understood. Animal models of perinatal c annabinoid exposure provide vide a useful tool for examining the devel opmental effects df cannabinoids. Behavioral consequences of maternal exposure to either cannabis preparations or to its main psychoactive c omponent, Delta(9)-tetrahydrocannabiriol (THC) in rat models are revie wed in this paper. Maternal exposure to cannabinoids, resulted in alte ration in the pattern; of ontogeny of spontaneous locomotor and explor atory behavior in the offspring. Adult animals exposed during gestatio nal and lactational periods exhibited persistent alterations in the be havioral responses to novelty, social interactions, sexual orientation and sexual behavior. They also showed a lack of habituation and react ivity to different illumination conditions. Adult offspring of both se xes also displayed a characteristic increase in spontaneous and water- induced grooming behavior. Some of the effects were dependent on the s ex of the animals being studied, and the dose of cannabinoid administe red to the mother during gestational and lactational periods. Maternal exposure to lowe doses of THC sensitized the adult offspring of both sexes to the reinforcing effects of morphine, as measured on a conditi oned place preference paradigm. The existence of sexual dimorphisms on the developmental effects of cannabinoids, the role of sex steroids, glucocorticoids, and pituitary hormones, the possible participation of cortical projecting monoaminergic systems, and the mediation of the r ecently described cannabinoid receptors are also analyzed. The informa tion obtained in animal studies is compared to the few data available on the long-term behavioral and cognitive effects on in utero exposure to cannabis in humans.