LONG-TERM BEHAVIORAL-EFFECTS OF PERINATAL EXPOSURE TO DELTA(9)-TETRAHYDROCANNABINOL IN RATS - POSSIBLE ROLE OF PITUITARY-ADRENAL AXIS

This work evaluated motor behaviors in adult male and female rats expo sed to delta(9)-tetrahydrocannabinol (THC, 5 mg/kg) during gestation a nd lactation. The possibility that perinatal THC exposure induces sens itization to other drugs of abuse has also been addressed by evaluatin g morphine place preference conditioning (MPP) in the adult offspring. Maternal exposure to THC resulted in long-term effects on motor behav iors such as rearing, grooming and sniffing, in the adult offsprings o f both sexes. Additionally, female offspring exposed to THC showed gre ater locomotor activity than controls, when measured using an actimete r. THC-exposed males exhibited an increased exploratory behavior in a plus-maze paradigm. When the adult animals were tested for MPP, THC-ex posed offspring of both sexes exhibited an enhanced sensitivity to the rewarding effects of a moderate dose of morphine (350 mu g/kg), an ef fect which was more marked in the males. These results showed that per inatal exposure to this psychoactive cannabinoid affected motor behavi ors in the adult, suggesting a psychomotor activation very similar to that observed after gestational exposure to other drugs of abuse. A po ssible role of a THC-induced hypothalamus-pituitary-adrenal (HPA) axis activation was also evaluated in the present study. THC-exposed femal es exhibited higher levels of both corticotropin releasing factor (CRF -41) in the medial basal hypothalamus (MBH) and plasma corticosterone, whereas THC-exposed males showed the lower levels of both endocrine p arameters. Since glucocorticoids are important modulators of both brai n development, and adult brain function, these results indicate a poss ible role of HPA axis disturbances in the mediation of the behavioral effects described after perinatal THC exposure.