Calcium homeostasis in cultured embryonic rat septohippocampal neurons is altered by ethanol and nerve growth factor before and during depolarization

Abstract

Ethanol and nerve growth factor (NGF) affect the survival of septohippocampal (SH) neurons. The effect of ethanol and NGF on calcium (Ca 2+) homeostasis in these neurons was investigated in this study. Changes in intracellular-free Ca 2+ concentration ([Ca 2+] i) were measured using indo-1 in cultured embryonic (E21) SH neurons before stimulation (basal) and during stimulation with 30 mM potassium cloride (KCl +). SH neurons were treated with 0, 100, 200, 400, or 800 mg% ethanol with NGF (+NGF) or without NGF (−NGF). NGF treatment decreased, while ethanol did not affect basal [Ca 2+] i. The combination of ethanol and NGF treatment led to increases in basal [Ca 2+] i. While [Ca 2+] i was lower during stimulation with KCl + following ethanol or NGF treatment, ethanol and NGF treatment together led to significantly greater increases or decreases in [Ca 2+] i compared to similarly treated NGF neurons. Responses of SH neurons were compared to those of medial septal (MS) neurons. Changes in [Ca 2+] i during treatment with ethanol and/or NGF were reduced in SH neurons compared with MS neurons. We conclude that changes in Ca 2+ homeostasis can occur in SH neurons in the presence of ethanol and/or NGF. The changes following ethanol treatment are enhanced by NGF. By altering Ca 2+ homeostasis, NGF may enhance the survival of SH neurons during ethanol-induced neurotoxicity.