5-HT, NO AND ASTROGLIA REALTIONSHIP IN PRENATAL ETHANOL EXPOSURE

EVRARD. SG; FERRARI, A; DUHALDE VEGA, M; TAGLIAFERRO, AP; BRUSCO, A

Orlando, FL. USA

Congreso; Society of Neuroscience 32º Annual Meeting; 2002

Serotonin (5HT), S-100b protein and nitric oxide (NO) are involved in brain development. We analyzed the expression of these molecules in a model of prenatal ethanol exposure (PEE). Female Wistar rats were orally exposed to ethanol 6.6% (v/v) ad libitum for 6 weeks before breeding and during gestation. Rat mothers continued receiving ethanol until pups reached 21-days-old. Control group received water. Offspring brains were processed by immunocytochemistry using antibodies directed to 5HT, 5HT transporter (5HT-T), 200 kDa neurofilaments (Nf200), neuronal NO synthase (nNOS), GFAP, or S-100b. Mesencephalic raphe nuclei and three brain target areas of 5-HT fibers were studied by image analysis. 5HT fibers sprouting was higher in layers V-VI of frontal cortex (FC) and in hippocampal CA1 area (H) than in striatum (S) which is in accordance with 5HT expression in raphe nuclei, where those fibers have their origin. In parallel, there was an increase in intracellular S-100b expression in reactive astrocytes of FC and H but not in S, while Nf200 expression was increased only in S and H but not in CF; nNOS expression was increased in FC and S but was not detectable in H. This differential expression evidenced variations in nerve tracts stabilization, astrogliosis and neuromodulators overexpression. These results were possibly due to the central role played by 5HT1A astroglial receptor in S-100b release and, direct or indirectly, in nNOS expression. The relationship among 5HT, S-100b and NO could be pharmacologically altered by means of 5HT1A modulation in order to minimize damage induced by PEE in offspring brains.