CHANGES IN THE TROPHIC FACTOR S-100ƒÒ AFTER SEROTONERGIC SYSTEM ALTERATION.

EVRARD, SG; TAGLIAFERRO AP,; RAMOS AJ,; DUHALDE VEGA M,; RUBIO, MD; BRUSCO, A

Hong Kong, China

Congreso; ISN and APSN Joint Meeting.; 2003

   Serotonin (5HT) plays an important role during central nervous system (CNS) development. 5HT actions seems to be mediated by the astroglial trophic factor S-100b released after astrocytic 5HT1A receptors stimulation. Parachloroamphetamine (PCA) and ethanol (EtOH) are drugs that alter the serotonergic system. We studied the developmental effects of these drugs on intracellular S-100b by administering them to Wistar rats. PCA (15 mg/kg each dose) were subcutaneously injected twice on P3 and P4 (P0 = birth day). EtOH 6.6% (v/v) in drinking water was given to females 6 weeks prior and during gestation until P0. The brains of the two sets of rat pups were immunocytochemically processed with anti-S100b antibodies on P5, P12, P20, P30 and P60 for the PCA-exposed pups and on the same days (except P12) for the EtOH-exposed pups. Intracellular astrocytic S-100b in hippocampal CA1 area (Hipp) and in the striatum (Strt) were evaluated by means of its relative optical density (ROD) using computer-assisted image analysis. In the PCA-exposed pups, S-100b ROD were increased on P5 and P12, returning to normal levels on P20 in Hipp and on P30 in Strt. In the EtOH-exposed rats, S-100b ROD were increased in both areas on all the studied postnatal ages. It is interesting that two different drugs, acting by two different mechanisms of action and in two different CNS developmental periods, alters the expression of the intracellular S-100b in a similar way. The altered intracellular expression of S-100b may be involved in the alterations of the CNS development described after the administration of these drugs.