Phosphorylation of B‐50 (GAP43) Is Correlated with Neurotransmitter Release in Rat Hippocampal Slices
作者:
L. V. Dekker,
P. N. E. Graan,
D. H. G. Versteeg,
A. B. Oestreicher,
W. H. Gispen,
期刊:
Journal of Neurochemistry
(WILEY Available online 1989)
卷期:
Volume 52,
issue 1
页码: 24-30
ISSN:0022-3042
年代: 1989
DOI:10.1111/j.1471-4159.1989.tb10893.x
出版商: Blackwell Publishing Ltd
关键词: B‐50/GAP43;Hippocampal slices;Neurotransmitter release;Protein kinase C;Protein phosphorylation
数据来源: WILEY
摘要:
Abstract:Recent studies have demonstrated that phorbol diesters enhance the release of various neurotransmitters. It is generally accepted that activation of protein kinase C (PKC) is the mechanism by which phorbol diesters act on neurotransmitter release. The action of PKC in neurotransmitter release is very likely mediated by phosphorylation of substrate proteins localized in the presynaptic nerve terminal. An important presynaptic substrate of PKC is B‐50. To investigate whether B‐50 mediates the actions of PKC in neurotransmitter release, we have studied B‐50 phosphorylation in intact rat hippocampal slices under conditions that stimulate or inhibit PKC and neurotransmitter release. The slices were labelled with [32P]orthophosphate. After treatment, the slices were homogenized, B‐50 was immunoprecipitated from the slice homogenate, and the incorporation of32P into B‐50 was determined. Chemical depolarization (30 μMK+) and the presence of phorbol diesters, conditions that stimulate neurotransmitter release, separately and in combination, also enhance B‐50 phosphorylation. Polymyxin B, an inhibitor of PKC and neurotransmitter release, decreases concentration dependently the depolarization‐induced stimulation of B‐50 phosphorylation. The effects of depolarization are not detectable at low extracellular Ca2+concentrations. It is concluded that in rat hippocampal slices B‐50 may mediate the action of PKC in neurot
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