Perinatal cannabinoid exposure modifies the sociosexual approach behavior and the mesolimbic dopaminergic activity of adult male rats

In the present work, we attempted to study whether hashish exposure during perinatal development affects sociosexual approach behavior in adult rats. To this end, we subjected adult female and male rats that had been perinatally exposed to hashish extracts to a sociosexual approach behavior test, completed with a dark-light emergence test and with a social interaction test. It was found that adult males perinatally exposed to hashish extracts exhibited marked changes in the behavioral patterns executed in the sociosexual approach behavior test; these changes did not exist in females. Thus, control males first visited the incentive male and took longer to visit the incentive female, whereas hashish-exposed males followed the opposite pattern. Moreover, hashish-exposed males spent more time in the vicinity of the incentive female, whereas they decreased their frequency of visits to, and the time spent in, the male incentive area. This behavior was observed early on, during the first third of the test, but became normalized and even inverted later on during the last two-thirds. Additionally, in the social interaction test, the normal reduction in the time spent in active social interaction following the exposure to a neophobic situation (high light levels) in controls did not occur in hashish-exposed males, although these exhibited a response in the dark-light emergence test similar to that of their corresponding controls. No changes were seen in spontaneous locomotor activity in both tests. These behavioral alterations observed in hashish-exposed males were paralleled by a significant decrease in L-3,4-dihydroxyphenylacetic acid contents in the limbic forebrain; this suggests a decreased activity of mesolimbic dopaminergic neurons. No effects were seen in females. Collectively, these results show that in the rat, perinatal cannabinoid exposure affects the sociosexual approach behavior and the mesolimbic dopaminergic activity in adulthood, although the effects were sexually dimorphic because they only appeared in the males.