Morphine Perinatal Exposure Induces Long-Lasting Negative Emotional States in Adult Offspring Rodents.

Psychoactive substances during pregnancy and lactation is a key problem in contemporary society, causing social, economic, and health disturbance. In 2010, about 30 million people used opioid analgesics for non-therapeutic purposes, and the prevalence of opioids use during pregnancy ranged from 1% to 21%, representing a public health problem. This study aimed to evaluate the long-lasting neurobehavioral and nociceptive consequences in adult offspring rats and mice exposed to morphine during intrauterine/lactation periods. Pregnant rats and mice were exposed subcutaneously to morphine (10 mg/kg/day) during 42 consecutive days (from the first day of pregnancy until the last day of lactation). Offspring were weighed on post-natal days (PND) 1, 5, 10, 15, 20, 30, and 60, and behavioral tasks (experiment 1) or nociceptive responses (experiment 2) were assessed at 75 days of age (adult life). Morphine-exposed female rats displayed increased spontaneous locomotor activity. More importantly, both males and female rats perinatally exposed to morphine displayed anxiety- and depressive-like behaviors. Morphine-exposed mice presented alterations in the nociceptive responses on the writhing test. This study showed that sex difference plays a role in pain threshold and that deleterious effects of morphine during pre/perinatal periods are nonrepairable in adulthood, which highlights the long-lasting clinical consequences related to anxiety, depression, and nociceptive disorders in adulthood followed by intrauterine and lactation morphine exposure.

Heavy Chronic Ethanol Exposure From Adolescence to Adulthood Induces Cerebellar Neuronal Loss and Motor Function Damage in Female Rats.

Over the last years, heavy ethanol consumption by teenagers/younger adults has increased considerably among females. However, few studies have addressed the long-term impact on brain structures' morphology and function of chronic exposure to high ethanol doses from adolescence to adulthood in females. In line with this idea, in the current study we investigated whether heavy chronic ethanol exposure during adolescence to adulthood may induce motor impairments and morphological and cellular alterations in the cerebellum of female rats. Adolescent female Wistar rats (35 days old) were treated with distilled water or ethanol (6.5 g/kg/day, 22.5% w/v) during 55 days by gavage. At 90 days of age, motor function of animals was assessed using open field (OF), pole, beam walking and rotarod tests. Following completion of behavioral tests, morphological and immunohistochemical analyses of the cerebellum were performed. Chronic ethanol exposure impaired significantly motor performance of female rats, inducing spontaneous locomotor activity deficits, bradykinesia, incoordination and motor learning disruption. Moreover, histological analysis revealed that ethanol exposure induced atrophy and neuronal loss in the cerebellum. These findings indicate that heavy ethanol exposure during adolescence is associated with long-lasting cerebellar degeneration and motor impairments in female rats.

Repeated cycles of binge-like ethanol exposure induce immediate and delayed neurobehavioral changes and hippocampal dysfunction in adolescent female rats.

Binge-like ethanol intake (BEI) is a socioeconomical problem among adolescents and increasingly affects women. BEI can leave a long-term imprint in the brain, but it is unknown if its effect on cognition and anxiety is cumulative on repeated binge-ethanol episodes. We now submitted female Wistar rats to repeated cycles of binge-like ethanol treatment by intragastrically administering ethanol (3.0 g/kg/day, 20% w/v ethanol; 3 days on/4 days off) starting at postnatal day 35 (PND35). To investigate the short-term effects of BEI during adolescence, rats underwent 1 or 4 cycles of BEI, being evaluated at PND37 and PND58, respectively: both groups displayed anxiety-like behavior in the open field and elevated plus-maze tests, as well as short-term memory deficits in the object recognition task; this was associated with transient decreases of BDNF levels and increases of GFAP levels in the hippocampus. To evaluate the short- and long-lasting effects of BEI in adulthood, rats were subjected to 8 cycles of BEI and evaluated after 7.5 h (PND86) or after 14 days of ethanol withdrawal (PND100). This caused a persistent anxiogenic profile whereas recognition memory was impaired on the short-term, but not 14 days post-administration. The reduced BDNF level observed shortly after BEI recovered upon withdrawal, whereas increased GFAP immunoreactivity was persistent up to 14 days post-administration in adulthood. These findings show that repeated binge-like ethanol episodes from adolescence to adulthood in female rats cause consistent and long-term alterations of anxiety and hippocampal astrogliosis, whereas they trigger a recognition memory deficit paralleled by lower hippocampal BDNF levels, both recovering upon ethanol withdrawal.