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Effects of In Vitro Anoxia and Low pH on Acetylcholine Release by Rat Brain Synaptosomes
Author(s) -
SanchezPrieto Jose,
Harvey Stephen A. K.,
Clark John B.
Publication year - 1987
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.1471-4159.1987.tb05658.x
Subject(s) - acetylcholine , in vitro , chemistry , synaptosome , biophysics , pharmacology , biochemistry , neuroscience , biology
Acetylcholine and choline release from rat brain synaptosomes have been measured using a chemilumines‐cent technique under a variety of conditions set up to mimic anoxic insult, including conditions of low pH (6.2) and the presence of lactate plus pyruvate as substrate. Lactate plus pyruvate as substrate consistently gave higher respiration rates than glucose alone, but with either substrate (glucose or lactate plus pyruvate) the omission of Ca 2+ caused an increase in respiration whereas a low pH caused a decreased respiration. Acetylcholine release under control conditions (glucose, pH 7.4) was Ca 2+ ‐dependent, stimulated by high K + concentrations, and decreased significantly during anoxia but recovered fully after a period of postanoxic oxygen‐ation. Low pH (6.2) suppressed K + stimulation of acetylcholine release, and after a period of anoxia at low pH the recovery of acetylcholine release was only partial. With lactate plus pyruvate as substrate, the effects of anoxia and/or low pH on acetylcholine release and its subsequent recovery were exacerbated. Choline release from synaptosomes, however, was not affected by anoxic/ionic conditions in the same way as acetylcholine release. At low pH (6.2) there was a marked reduction in choline release both under aerobic and anoxic conditions. These results suggest that acetylcholine release per se from the nerve is very sensitive to anoxic insult and that the low pH occurring during anoxia may be an important contributory factor.