Time course of nerve growth factor modulation of ethanol inhibition of Ca2+ currents in PC12 cells.
The effects of 25 mM ethanol on high voltage-activated (HVA) L-type Ca2+ channels in nerve growth factor (NGF)-treated, dibutyryl cyclic AMP (dbcAMP)-treated and undifferentiated (UND) PC12 cells were examined. Channels in NGF-treated cells became less sensitive to the effects of ethanol. The time course of the NGF-induced reduction in ethanol inhibition occurred in two phases. The first phase of reduced inhibition was observed after 2 h of NGF exposure and was complete after 5 h. The second phase of reduced inhibition developed over a period of 10-96 h and was reversible after removal of NGF. Exposure to dbcAMP for 2 h also caused a transient drop in ethanol inhibition, but the second phase of decreased ethanol sensitivity was absent. Thus, increased levels of cAMP do not appear to be involved in the longer-term effects of NGF on the decrease in ethanol inhibition of Ca2+ channels, whereas the effects observed at 2 h may involve cAMP.
Mullikin-Kilpatrick
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Department of Pharmacology, University of Massachusetts Medical Center, Worcester 01655.
Treistman
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D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology*; D002454:Cell Differentiation; D000242:Cyclic AMP / Q000502:physiology; D000431:Ethanol / Q000494:pharmacology*; D005071:Evoked Potentials / Q000187:drug effects; D007700:Kinetics; D009414:Nerve Growth Factors / Q000494:pharmacology*; D016716:PC12 Cells; D051381:Rats; D013997:Time Factors
D002121:Calcium Channel Blockers; D015220:Calcium Channels; D009414:Nerve Growth Factors; D000431:Ethanol; D003994:Bucladesine; D000242:Cyclic AMP