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GABA UPTAKE IN RAT CENTRAL NERVOUS SYSTEM: COMPARISON OF UPTAKE IN SLICES AND HOMOGENATES AND THE EFFECTS OF SOME INHIBITORS
Author(s) -
Iversen L. L.,
Johnston G. A. R.
Publication year - 1971
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.1471-4159.1971.tb09600.x
Subject(s) - cerebral cortex , glycine , amino acid , biochemistry , aminooxyacetic acid , chemistry , non competitive inhibition , synaptosome , biology , enzyme , in vitro , endocrinology
— Fifty‐two substances were tested as inhibitors of the uptake of [ 3 H]GABA in slices of rat cerebral cortex. Among GABA analogues tested, only the 2‐fluoro, 3‐hydroxy and 2‐amino compounds had affinities for the uptake mechanism comparable to that of GABA. [ 3 H]GABA uptake was also potently inhibited by p ‐chloromercuriphenylsulphonate, N ‐ethylmaleimide, chlorpromazine and haloperidol. No inhibitors were found to act in a competitive manner with respect to GABA. [ 3 H]GABA uptake was also examined in homogenates of cerebral cortex and other regions of CNS. There was a rapid uptake of [ 3 H]GABA into particles when homogenate samples were incubated with the labelled amino acid; this uptake had similar kinetic properties and inhibitor sensitivity to that observed in slices of intact tissue. Density gradient centrifugation experiments indicated that the particles responsible for the uptake of [ 3 H]GABA in homogenates were probably synaptosomes. Uptake of [ 3 H]GABA also occurred in slices and homogenates of rat spinal cord, and evidence was obtained by the simultaneous labelling of homogenates with [ 14 C]glycine and [ 3 H]GABA that these two amino acids were taken up by different nerve terminals in this region.