Influência da infusão contínua e central de agonista CB1 sobre o comportamento materno de ratas lactantes e consequências comportamentais nos descendentes

Abstract

It has been demonstrated that systemic administration of cannabinoids in lactating rodents affect maternal behavior. Therefore, the objective was to determine what changes, specifically, in maternal care caused by chronic infusion of central CB1 receptor agonist (WIN 55,212-2) at doses of 10 and 100nmol. Analyses of maternal behavior were performed in 4 sessions daily (3 during the light phase and 1 during the dark phase) of 72 minutes each, being recorded from 3 in 3 minutes totaling 25 observations per session (so 100 daily observations) . The result of the analysis, during infusion of the drug, indicated decreased time to licking and consequent increase in the time that the rat is feeding. Even after the period of drug infusion (7 days), the total maternal behavior remained decreased. How interference occurred during the neonatal period that cause variations in maternal care may persist and influence the phenotype of the offspring, were evaluated possible changes in anxiety and fear responses in the offspring when in adulthood. Therefore, males and females puppies (when completed 8 weeks of life), were tested in the open-field, elevated plus maze and fear conditioning to context. The results show that male offspring have lower latency to display the first freezing in this fear test. Moreover, the females showed only elevated blood pressure when subjected to the same test. Together, the results suggest that cannabinoids decrease maternal care in lactating rats, mainly licking, and even after cessation of drug infusion, the reduction of total maternal behavior remains. This decrease in maternal care reflected mainly in male offspring, increasing responses related to fear.