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Relations Between the Extracellular Concentrations of Choline and Acetylcholine in Rat Striatum
Author(s) -
Ikarashi Yasushi,
Takahashi Akira,
Ishimaru Hirohisa,
Arai Tadashi,
Maruyama Yuji
Publication year - 1997
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 - 10.1046/j.1471-4159.1997.69031246.x
Subject(s) - acetylcholine , microdialysis , sulpiride , extracellular , chemistry , striatum , atropine , cholinergic , muscarinic antagonist , antagonist , endocrinology , medicine , choline , muscarinic acetylcholine receptor , pharmacology , dopamine , biology , biochemistry , receptor
Changes in extracellular levels of acetylcholine (ACh) and choline (Ch) in the striatum of rats were examined by in vivo microdialysis after intraperitoneal injections of drugs. A dopamine D 2 antagonist, sulpiride (20 mg/kg), and a muscarinic antagonist, atropine (3.5 mg/kg), increased ACh levels and decreased Ch levels. On the contrary, the D 2 agonist (±)‐2‐( N ‐phenylethyl‐ N ‐propyl)amino‐5‐hydroxytetralin (N‐434; 5 mg/kg) and an anesthetic, pentobarbital (50 mg/kg), decreased ACh levels and increased Ch levels. Perfusion of 10 µ M hemicholinium‐3 (HC‐3), a Ch uptake inhibitor, through the striatum induced a complete inhibition of ACh release and increased Ch levels in all drug‐treated groups. The degree of relative increase in the level of Ch induced by HC‐3 differed among the drug‐pretreated groups; compared with the control group, the relative increase was larger in the sulpiride‐ and atropine‐treated groups and smaller in the N‐434 and pentobarbital‐treated groups. Thus, we demonstrated reciprocal relations between extracellular concentrations of Ch and ACh after treatments by drugs. The data suggest that in the striatum, which is rich in cholinergic innervation, the extracellular Ch concentration is to a large extent determined by activity of the cholinergic transmission reflected in high‐affinity choline uptake.