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Determination of Endogenous Acetylcholine Release in Freely Moving Rats by Transstriatal Dialysis Coupled to a Radioenzymatic Assay: Effect of Drugs
Author(s) -
Consolo Silvana,
Wu Chun Fu,
Fiorentini Francesco,
Ladinsky Herbert,
Vezzani Annamaria
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.tb05686.x
Subject(s) - acetylcholine , physostigmine , chemistry , microdialysis , oxotremorine , choline , endogeny , endocrinology , atropine , cholinergic , medicine , acetylcholinesterase , extracellular , muscarinic acetylcholine receptor , biochemistry , biology , enzyme , receptor
The technique of intracerebral dialysis in combination with a sensitive and specific radioenzymatic method was used for recovery and quantification of endogenous extracellular acetylcholine from the striata of freely moving rats. A thin dialysis tube was inserted transversally through the caudate nuclei, and the tube was perfused with Ringer solution, pH 6.1, at a constant rate of 2 μl min −1 . The perfusates were collected at 10‐min intervals. In the presence of 1 and 10 μ M physostigmine, acetylcholine release was 4.5 ± 0.02 and 7.3 ± 0.3 pmol/10 min, respectively (not corrected for recovery). The latter concentration of the acetylcholinesterase inhibitor was used in all experiments. Under basal conditions, acetylcholine output was stable over at least 4 h. A depolarizing K + concentration produced a sharp, reversible 87% increase in acetylcholine output. Both the basal and K + ‐stimulated release were Ca 2+ dependent. The choline uptake inhibitor hemicholinium‐3 (20 μg intracerebroventricularly) reduced striatal acetylcholine output to 35% of the basal value within 90 min. Scopolamine (0.34 mg/kg s.c.) provoked a sharp enhancement of acetylcholine release of ∼63% over basal values, whereas oxotremorine (0.53 mg/kg i.p.) transiently reduced acetylcholine release by 54%. These results indicate the physiological and pharmacological suitability of transstriatal dialysis for monitoring endogenous acetylcholine release.