Background and purpose: Cannabidiol (CBD) is a non‐psychotomimetic compound fromCannabis sativawhich induces anxiolytic‐ and antipsychotic‐like effects in rodents. These effects could be mediated by facilitation of the endocannabinoid system or by the activation of 5‐HT_1Areceptors. As either of these mechanisms could promote adaptation to inescapable stress, the aim of the present work was to test the hypothesis that CBD would attenuate the autonomic and behavioural consequences of restraint stress (RS). We also investigated if the responses to CBD depended on activation of 5‐HT_1Areceptors.Experimental approach: Male Wistar rats received i.p. injections of vehicle or CBD (1, 10 or 20 mg kg⁻¹) and 30 min later were submitted to 60 min of restraint where their cardiovascular responses were recorded. The protocol of the second experiment was similar to the first one except that animals received i.p. injections of the 5‐HT_1Areceptor antagonist WAY100635 (0.1 mg kg⁻¹) before CBD treatment and exposure to restraint. 24 h later they were also tested in the elevated plus‐maze (EPM), an animal model of anxiety.Key results: Exposure to RS increased blood pressure and heart rate and induced an anxiogenic response in the EPM 24 h later. These effects were attenuated by CBD. WAY100635 by itself did not change the cardiovascular and anxiogenic response to RS, but blocked the effects of CBD.Conclusion and implications: The results suggest that CBD can attenuate acute autonomic responses to stress and its delayed emotional consequences by facilitating 5‐HT_1Areceptor‐mediated neurotransmission.

Background/Aims: Fluoxetine (FLX) has been widely prescribed for depression during pregnancy and/or lactation. Since serotonin is a neurotrophic factor, the use of FLX by mothers could disrupt brain development resulting in behavioral alterations in their progeny. This study evaluated the effects of developmental FLX exposure on anxiety, depression, aggressivity and pain sensitivity of male and female mice pups. Methods: Swiss dams were treated daily, by gavage, with 7.5 mg/kg of FLX during pregnancy and lactation. Pups were submitted to open-field, forced swimming, elevated plus-maze, intruder-resident and hot plate tests at adolescence and adulthood. Results and Conclusion: In male pups, exposure to FLX decreased ambulation at postnatal day (PND) 40 and tended (p = 0.07) to increase the latency to the first attack in the intruder-resident test at PND 70, suggesting decreased impulsivity. In female pups, FLX exposure increased immobility time in the forced swimming test at both PND 30 and 70, which is interpreted as depressive-like behavior. In conclusion, our results suggest that maternal exposure to FLX during pregnancy and lactation results in enduring behavioral alterations in male and female pups throughout life.

The ventral portion of the medial prefrontal cortex (vMPFC) has been related to the expression of contextual fear conditioning. This study investigate