Acute and Chronic Maternal Separation: Alcohol Intake on Adolescent Rats

ACOSTA, GB; ODEON, MM

Cancún

Conferencia; ISN Satellite Conference: The brain in flux: genetic, physiologic and therapeutic perspectives on transporters in the CNS; 2013

ISN-ASN

There is increasing evidence that environmental factors, particularly stressful events experienced early in life, increase the risk of developing a psychiatric illness and/or a behavioural disorder in adulthood. Extracellular glutamate (Glu) concentrations are regulated by glia cells and neuronal transporters proteins. We evaluated the effects of acute and chronic maternal separation (AMS and CMS) plus cold stress on the expression and regulation of glutamate transporters (TGlu) in the developing and adult CNS. Rat pups subjected to MS were separated from their mother at postnatal day (PD) 2, 7 or 13 and were placed in separation cages for 1 h. Later were returned to the home cage with their mother. Glu uptake from frontal cortex (FC) and hippocampus (Hic) was studied. In the both groups, acute and chronic we detected an increment of Vmax and a decreased affinity. Western blott analysis was used to evaluate expression of TGlu subtypes, EACC and GLT1 in FC and Hic. In acute group there was a significant increase in GLT1 both at PD5 and at PD13 in FC, while in Hic there was only an increase at PD7 in this transporter. On the other hand, western blotting shown at PD13 acute group a significant reduction in EACC (neuronal) expression in FC, though the chronic group increased EACC expression at PD55. In Hic, acute treatment produced an increase in the neuronal transporter at all ages analyzed, while chronic treatment increased EACC expression both at PD55 and PD63, whereas at PD57 showed a significant decrease. These results demonstrate that adverse early life events have profound and persistent effects on brain function. We investigated the consequences of chronic early life manipulations and alcohol intake on GluT on adolescent rats. In CMS, the pups were separated from their mothers and exposed to cold stress for 1 h during 20 d. Then they were exposed to a voluntary ethanol intake for 7 days. We measured Glu uptake using time course, kinetic parameters on synaptosomes from FC and Hic. Along with immunoblotting we showed detectable levels of: EAAC and GLT-1 in different treatments and evaluated the plasmatic levels of corticosterone, catecholamines and transaminases enzymes. These results suggest that an exposure to CMS and alcohol after birth modify GluT activity and affect the hormones in hypothalamic-pituitary-adrenal (HPA) axis, which could be relevant to the function of GluT in the adult rat brain. In conclusion: the early postnatal period and the bonds between mother and infant seem particularly important in the development and shaping of normal stress response and emotional behaviour.