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THE FORMATION OF CHOLINE AND OF ACETYLCHOLTNE BY BRAIN IN VITRO
Author(s) -
Collier B.,
Poon P.,
Salehmoghaddam S.
Publication year - 1972
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.1471-4159.1972.tb01252.x
Subject(s) - choline , acetylcholine , free nerve ending , incubation , synaptosome , chemistry , in vitro , brain tissue , biochemistry , incubation period , endocrinology , medicine , biology , anatomy
— Free choline and acetylcholine (ACh) in mouse or rat brain were assayed biologically. The subcellular distribution of ACh in brain slices that had been incubated in the presence of eserine was compared to that in control brain; during incubation, the ACh outside nerve endings increased four‐fold, the ACh released from synaptosomes by osmotic shock doubled but the ACh bound firmly within nerve endings did not increase. The two nerve ending stores of ACh were labelled to similar specific radioactivities when slices were incubated with [ 3 H]choline, but the specific radioactivity of the ACh formed was much lower than that of the added choline. Tissue incubated in the presence of eserine released choline and ACh into the medium and the tissue levels of both substances increased. Brain tissue exposed to Na + ‐free medium lost 84 per cent of its ACh and 66 per cent of its free choline; the amounts of both substances returned towards control values during subsequent incubation in a normal‐Na + medium (choline‐free). Both the ACh outside nerve endings and the ACh associated with synaptosomes were depleted when tissue was incubated in Na + ‐free medium.