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THE UPTAKE, METABOLISM AND RELEASE OF HOMOCHOLINE: STUDIES WITH RAT BRAIN SYNAPTOSOMES AND CAT SUPERIOR CERVICAL GANGLION
Author(s) -
COLLIER B.,
LOVAT S.,
ILSON D.,
BARKER L. A.,
MITTAG T. W.
Publication year - 1977
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.1471-4159.1977.tb07752.x
Subject(s) - superior cervical ganglion , choline acetyltransferase , stimulation , acetylation , acetylcholine , cervical ganglia , chemistry , cholinergic , choline , free nerve ending , ganglion , in vitro , synaptosome , biophysics , biochemistry , anatomy , endocrinology , biology , gene
— The accumulation of [ 3 H]homocholine (3‐trimethylamino‐propan‐1‐01) by isolated synaptosomes prepared from rat brain was resolved kinetically into a high ( K T = 3.0 μM) and a low ( K T = 14.5 μM) affinity system. Although homocholine was not acetylated by solubilized choline acetyltransferase, 64% of the homocholine accumulated by intact synaptosomes via the high affinity uptake process was acetylated. Homocholine was also acetylated in the superior cervical ganglion of the cat, and the amount of acetylhomocholine formed was increased (12‐fold) by preganglionic nerve stimulation. In ganglia, acetylhomocholine was available for release by preganglionic nerve impulses, and its release was Ca 2+ ‐dependent, It is concluded that homocholine can form a cholinergic false transmitter, and that the substrate specificity of choline acetyltransferase in vitro might be different from that in situ.