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THE UPTAKE AND RELEASE OF [ 3 H]‐2‐AMINO‐6,7‐DIHYDROXY1,2,3,4‐TETRAHYDRONAPHTHALENE (ADTN) BY STRIATAL NERVE TERMINALS
Author(s) -
DAVIS A.,
ROBERTS P.J.,
WOODRUFF G.N.
Publication year - 1978
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1978.tb07788.x
Subject(s) - nomifensine , benztropine , dopamine , striatum , dopaminergic , chemistry , neurotransmitter , reserpine , calcium , pharmacology , amphetamine , biophysics , biochemistry , endocrinology , biology , receptor , organic chemistry
1 A study has been made of the uptake and release of [G‐ 3 H]‐2‐amino 6,7‐dihydroxy‐1, 2,3,4‐tetra‐hydronaphthalene (ADTN) by crude striatal synaptosomes of the rat. 2 Uptake was rapid, temperature‐dependent and could be suppressed by a variety of metabolic inhibitors. 3 The Michaelis‐Menten kinetics indicated the presence of two distinct transport systems in the striatum which were of much higher capacity than those found in the cerebellum, which lacks dopaminergic innervation. 4 Uptake of [ 3 H]‐ADTN was strongly inhibited by dopamine and the two potent dopamine‐uptake inhibitors, benztropine and nomifensine, but only weakly by imipramine and amphetamine (the latter in non‐reserpine‐treated animals). 5 Accumulated [ 3 H]‐ADTN could be released from striatal slices by elevated K + . A similar release was evoked upon the addition of the ionophore, A23187. 6 The most potent releaser of [ 3 H]‐ADTN was (+)‐amphetamine. This effect occurred at concentrations inactive against ADTN uptake. The neuroleptic ris‐flupenthixol produced an inhibition of the spontaneous release. 7 It is concluded that [ 3 H]‐ADTN is accumulated preferentially into areas of the rat brain rich in dopamine. The pharmacological specificity of the uptake suggests that it is a good substrate for the dopamine carrier. Following uptake, [ 3 H]‐ADTN may be released by K + and a calcium ionophore, which raises the possibility that ADTN might act as a false transmitter.