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The Inactivation of γ‐Aminobutyric Acid Transaminase in Dissociated Neuronal Cultures from Spinal Cord
Author(s) -
Rando Robert R.,
Bangerter Faan Wen,
Farb David H.
Publication year - 1981
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.1471-4159.1981.tb01690.x
Subject(s) - gaba transaminase , aminobutyric acid , glutamate receptor , neurotransmitter , glutamate decarboxylase , biochemistry , enzyme , biology , transaminase , inhibitory postsynaptic potential , gabaergic , gamma aminobutyric acid , chemistry , neuroscience , receptor
Abstract: It had previously been shown that dissociated cell cultures from chick embryo spinal cord have a high affinity uptake system for the neurotransmitter γ‐aminobutyric acid (GABA) and make functional inhibitory synaptic contacts as determined by electrophysiology (Farb et al., 1979). It is shown here that these cultures can synthesize GABA from added glutamate in a glutamate decarboxylase‐dependent reaction. Furthermore, these cultures have a functional GABA transaminase that degrades the neurotransmitter. This enzyme can be specifically and irreversibly blocked with gabaculine. A 15 min incubation with 10 −6 M‐gabaculine completely inactivates the enzyme. The inactivation of the enzyme leads to an increase in GABA levels. Long‐term incubation (16 days) of gabaculine in the medium does not appear to alter high affinity GABA transport, suggesting that the drug is not toxic to cells capable of accumulating GABA.