An Ion Channel Locus for the Protein Kinase C Potentiation of Transmitter Glutamate Release from Guinea Pig Cerebrocortical Synaptosomes
- 5 October 1991
- journal article
- Published by Wiley in Journal of Neurochemistry
- Vol. 57 (4) , 1398-1404
- https://doi.org/10.1111/j.1471-4159.1991.tb08306.x
Abstract
The mechanism by which protein kinase C (PKC) activates transmitter release from guinea pig cerebrocortical synaptosomes was investigated by employing parallel fluorescent assays of glutamate release, cytoplasmic free Ca2+, and plasma membrane potential. 4β-Phorbol dibutyrate (4β- PDBu) enhances the Ca2+-dependent, 4-aminopyridine (4AP)-evoked release of glutamate from synaptosomes, the 4AP-evoked elevation of cytoplasmic free Ca2+, and the 4AP- evoked depolarization of the plasma membrane. 4β-PDBu itself causes a slow depolarization, which may underlie the small effect of 4β-PDBu on spontaneous, KCI-evoked, and Ca2+-independent/4AP-evoked glutamate release. Because 4AP (but not KCI) generates spontaneous, tetrodotoxin-sensitive action potentials in synaptosomes, a major locus of presynaptic PKC action is to enhance these action potentials, perhaps by inhibiting delayed rectifier K+ channels.Keywords
This publication has 49 references indexed in Scilit:
- Differential release of amino acids, neuropeptides, and catecholamines from isolated nerve terminalsNeuron, 1991
- Dendrotoxin and charybdotoxin increase the cytosolic concentration of free Ca2+ in cerebrocortical synaptosomes: An effect not shared by apaminFEBS Letters, 1989
- Phorbol-12,13-dibutyrate antagonizes while forskolin potentiates the presynaptic autoreceptor-mediated inhibition of [3H]-5-hydroxytryptamine release in rat hypothalamic slicesSynapse, 1989
- Activators of protein kinase C and phenylephrine depolarize the astrocyte membrane by reducing the K+ permeabilityNeuroscience Letters, 1988
- The pharmacology of potassium channels and their therapeutic potentialTrends in Pharmacological Sciences, 1988
- Characterization of the Exocytotic Release of Glutamate from Guinea‐Pig Cerebral Cortical SynaptosomesJournal of Neurochemistry, 1987
- The role of protein kinase C in the regulation of ion channels and neurotransmitter releaseTrends in Neurosciences, 1987
- Acetylcholine release from guinea pig caudate slices evoked by phorbol ester and calciumFEBS Letters, 1986
- Dependence of cytoplasmic calcium transients on the membrane potential in isolated nerve endings of the guinea pigBiochimica et Biophysica Acta (BBA) - Biomembranes, 1985
- The phorbol ester TPA increases the affinity of exocytosis for calcium in ‘leaky’ adrenal medullary cellsFEBS Letters, 1983