Ethanol's effect on intracellular signal pathways in prenatal rat cortical neurons is GABA_B1 dependent

Abstract

To confirm the modulation role of GABA(B) on ethanol' effects, we studied the effects of ethanol on the neuronal intracellular signals, protein kinase A (PKA) and cAMP-response element binding protein (CREB), by using a system where GABA(B1) receptors were specifically knocked down in the in vitro cultivated cortical neurons. The results showed that the PKA alpha subunit was increased with ethanol treatment, and could be further increased by administering baclofen and phaclofen. By contrast, baclofen and/or phaclofen could decrease ethanol's up-regulation effects on PKA alpha subunit expression in primary cultured cortical neurons in which the GABA(B1) receptor was specifically knocked down using GABA(B1) receptor RNA interference. Furthermore, these effects could lead to changes of phospho (p)-CREB expression, which showed the same expression pattern as PKA. Finally, we observed changes of GABA(B1), PKA, and p-CREB distribution within the same neuronal cells. These results showed that the GABA(B) receptors are critical to ethanol's cellular effects, which occur via modulating the PKA and CREB transcription pathway, and may be an underlying cause of ethanol's effects.

Neuroprotective effect of vitamin C against the ethanol and nicotine modulation of GABAB receptor and PKA‐α expression in prenatal rat brain

“…1 and 2, lanes 4, 5, 8, and 9). These results are consistent with our previous reports that baclofen and phaclofen's effect was time-dependent and showed different effects upon 30-min and 1-h treatment, and baclofen-induced significant increasing effects were observed under normal conditions for short-term exposure on both GABA B1 and GABA B2 R expressions (Lee et al, 2007(Lee et al, , 2008.…”

Ethanol Neurotoxicity in the Developing Cerebellum: Underlying Mechanisms and Implications

“…Oxidative damage of mitochondria releases cytochrome C and activates caspase pathways, which lead to cell death. Various in vitro , as well as in vivo , data suggest that prenatal and postnatal ethanol induces elevated level of oxidative stress either by generation of free radicals (ROS/RNS) or disruption of antioxidative defense mechanisms and, thereby, promotes apoptotic cell death in the cerebellum of rodent brains [5,22,23,24,25,26,27,28,29]. Ethanol exposure to in vitro cultures of cortical neurons [26] and fetal rhombencephalic neurons [30] generates ROS and induces mitochondrial membrane depolarization and apoptosis (Figure 2).…”

In vivo and in vitro ethanol exposure in prenatal rat brain: GABAB receptor modulation on dopamine D1 receptor and protein kinase A

“…Genetic manipulation of the cAMP-PKA pathway modulates ethanol intake and sensitivity to its sedative effects (Thiele et al, 2000;Wand et al, 2001). The GABA B R is also coupled to regulation of cAMP-PKA signaling system and can activate the G-protein upon ethanol treatment (Lee et al, 2007). The activation of GABA B R potentiates the corticotrophin-releasing hormone stimulation of AC activity through the b/g subunits of the pertussis toxin (PTX)-sensitive G protein G(i)/G(o) in the rat frontal cortex (Onali and Olianas, 2001).…”