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Wednesday, October 26, 2011

Modulation by the GABAB receptor siRNA of ethanol-mediated PKA-α, CaMKII, and p-CREB intracellular signaling in prenatal rat hippocampal neurons



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 γ-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-α (PKA-α), 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-α.

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.


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