Effect of ethanol on neurotrophin-mediated cell survival and receptor expression in cultures of cortical neurons.
The interaction of ethanol and neurotrophin-mediated cell survival was examined in primary cultures of cortical neurons. Cells were obtained from rat fetuses on gestational day 16 and maintained in a medium supplemented with either 10% or 1.0% fetal calf serum (FCS). Exogenous nerve growth factor (NGF; 20 ng/ml), brain-derived neurotrophic factor (BDNF; 20 ng/ml) or neurotrophin 3 (NT-3; 20 ng/ml) was added to the cultures alone, or in combination with ethanol (400 mg/dl). The number of viable neurons was determined after a 48 h treatment with a growth factor and/or ethanol. The effects of ethanol on the expression of high affinity neurotrophin receptors (trkA, trkB, and trkC) and the low-affinity receptor (p75), were analyzed using Western immunoblots. In untreated cultures, 22.7% and 26.3% of the cells raised in a medium containing 10% and 1.0% FCS, respectively, were lost. Only NGF prevented the death of the cultured cortical neurons. Ethanol was toxic; it caused a 23.5% and 16.7% loss of cells (for cells grown in a medium containing 10% and 1.0% FCS, respectively) beyond that occurring 'naturally' in an untreated culture. Ethanol completely blocked the NGF-mediated cell survival. In general, BDNF and NT-3 did not offset the toxic effect of ethanol. Immunoblotting studies showed that the expression of p75 was significantly (p < 0.05) lower (40%) in ethanol-treated cultures, but ethanol did not affect trk expression. Thus, ethanol has specific effects upon NGF-mediated cell survival and the effects on the low affinity receptor imply that p75 specifically plays an important role in NGF signaling.
Seabold
G K
GK
Department of Psychiatry, University of Iowa College of Medicine, Iowa City 52242-1000, USA.
Luo
J
J
Miller
M W
MW
D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism; D002470:Cell Survival / Q000502:physiology; D002478:Cells, Cultured; D002492:Central Nervous System Depressants / Q000494:pharmacology*; D002540:Cerebral Cortex / Q000166:cytology*; D000431:Ethanol / Q000494:pharmacology*; D005260:Female; D005333:Fetus / Q000737:chemistry / Q000187:drug effects; D009414:Nerve Growth Factors / Q000378:metabolism*; D009474:Neurons / Q000737:chemistry / Q000166:cytology / Q000187:drug effects*; D018696:Neuroprotective Agents / Q000032:analysis; D020933:Neurotrophin 3; D011247:Pregnancy; D011518:Proto-Oncogene Proteins / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D020794:Receptor Protein-Tyrosine Kinases / Q000032:analysis; D020801:Receptor, Ciliary Neurotrophic Factor; D020800:Receptor, Nerve Growth Factor; D020917:Receptor, trkA; D020812:Receptor, trkC; D017475:Receptors, Nerve Growth Factor / Q000032:analysis
D019208:Brain-Derived Neurotrophic Factor; D002492:Central Nervous System Depressants; D009414:Nerve Growth Factors; D018696:Neuroprotective Agents; D020933:Neurotrophin 3; D011518:Proto-Oncogene Proteins; D020801:Receptor, Ciliary Neurotrophic Factor; D020800:Receptor, Nerve Growth Factor; D017475:Receptors, Nerve Growth Factor; D000431:Ethanol; D020794:Receptor Protein-Tyrosine Kinases; D020917:Receptor, trkA; D020812:Receptor, trkC