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A Role for Transglutaminase in Neurotransmitter Release by Rat Brain Synaptosomes
Author(s) -
Pastuszko Anna,
Wilson David F.,
Erecińska Maria
Publication year - 1986
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1986.tb12996.x
Subject(s) - neurotransmitter , tissue transglutaminase , synaptosome , chemistry , neuroscience , biochemistry , biology , enzyme , central nervous system
Rat brain synaptosomes exhibit calcium‐dependent transglutaminase activity. This activity, measured in detergent‐treated or sonicated preparations, was six‐ to sevenfold lower than that in the liver. The synaptosomal transglutaminase was inhibited by various amines and α‐difluoromethylornithine, compounds known to inhibit activity of this enzyme in other tissues. The inhibitors of transglutaminase induced release of catecholamines, but not of γ‐aminobutyric acid, from synaptosomes both under basal and K + ‐stimulated conditions. The concentrations of the agents that caused stimulation of catecholamine release were approximately the same as those that inhibited the activity of transglutaminase. Stimulation of release was largely reduced by the withdrawal of calcium from the incubation medium. Inhibitors of transglutaminase had little effect either on the uptakes of neurotransmitters or the amounts of deaminated products of catecholamine degradation released into the medium. It is suggested that a synaptosomal transglutaminase is involved in suppressing vesicular release of catecholamines by resting (nondepolarized) neurons and that this action may also be a part of negative feedback control which prevents excessive transmitter release at the synapse during increased neuronal activity.