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Continuous Determination by a Chemiluminescent Method of Acetylcholine Release and Compartmentation in Torpedo Electric Organ Synaptosomes
Author(s) -
Israël Maurice,
Lesbats Bernard
Publication year - 1981
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.1471-4159.1981.tb06317.x
Subject(s) - torpedo , electric organ , acetylcholine , chemiluminescence , chemistry , biochemistry , chromatography , biology , acetylcholine receptor , pharmacology , receptor
The detection of acetylcholine (ACh) with a chemiluminescent procedure enables one to follow continuously the release of transmitter from stimulated synaptosomes and to study the compartmentation of ACh in resting and active nerve terminals. A compartment of ACh liberated almost entirely by a single freezing and thawing could be directly measured and compared with a compartment of ACh resistant to several cycles of freezing and thawing but liberated by a detergent (60–70% of the total). It is the compartment liberated by freezing and thawing that is reduced when synaptosomes are stimulated. Up to half the total synaptosomal ACh content is readily releasable provided the calcium entry is maintained, or if a strong releasing agent such as the venom of Glycera convoluta is used. In addition, it is shown that synaptosomes contain only negligible amounts of choline, and that the proportion of the two ACh compartments is not influenced by changing extracellular calcium just before their determination.