RESUMO
Fetal alcohol syndrome (FAS) is a developmental neuropathology resulting from in utero exposure to ethanol; many of ethanol's effects are likely to be mediated by the neurotransmitter gamma-aminobutyric acid (GABA). We studied modulation of the neurotransmitter receptor GABABR and its capacity for intracellular signal transduction under conditions of ethanol treatment (ET) and RNA interference to investigate a potential role for GABA signaling in FAS. ET increased GABAB1R protein levels, but decreased protein kinase A-alpha (PKA-alpha), calcium/calmodulin-dependent protein kinase II (CaMKII) and phosphorylation of cAMP-response element binding protein (p-CREB), in cultured hippocampal neurons harvested at gestation day 17.5. To elucidate GABAB1R response to ethanol, we observed the effects of a GABABR agonist and antagonist in pharmacotherapy for ethanol abuse. Baclofen increased GABABR, CaMKII and p-CREB levels, whereas phaclofen decreased GABABR, CaMKII and p-CREB levels except PKA-alpha. Furthermore, when GABAB1R was knocked down by siRNA treatment, CaMKII and p-CREB levels were reduced upon ET. We speculate that stimulation of GABAB1R activity by ET can modulate CaMKII and p-CREB signaling to detrimental effect on fetal brain development.