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Reserpine Pretreatment Prevents Increases in Extracellular Striatal Dopamine Following L‐DOPA Administration in Rats with Nigrostriatal Denervation
Author(s) -
Kannari Kazuya,
Tanaka Hiroyasu,
Maeda Tetsuya,
Tomiyama Masahiko,
Suda Toshihiro,
Matsunaga Muneo
Publication year - 2000
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.1471-4159.2000.0740263.x
Subject(s) - reserpine , extracellular , microdialysis , dopaminergic , striatum , dopamine , medicine , endocrinology , denervation , chemistry , nigrostriatal pathway , substantia nigra , biology , biochemistry
The influence of L‐DOPA and reserpine on extracellular dopamine (DA) levels in the striatum of intact and dopaminergic denervated rats was studied using the brain microdialysis technique. In intact rats, reserpine (5 mg/kg s.c.) reduced extracellular DA levels to 4% of basal values. L‐DOPA (50 mg/kg i.p.) had no effect on extracellular DA levels in reserpine‐pretreated rats. In rats with 6‐hydroxydopamine‐induced lesion of the nigrostriatal dopaminergic system, basal levels of extracellular DA were low but markedly increased by L‐DOPA (50 mg/kg i.p.). In 6‐hydroxydopamine‐lesioned rats, pretreatment with reserpine (5 mg/kg s.c.) diminished L‐DOPA (50 mg/kg i.p.)‐induced increases in extracellular DA levels to 16% of those obtained in denervated animals not pretreated with reserpine ( p < 0.01). These results suggest that in the intact striatum, extracellular DA stems mainly from vesicular storage sites and that in the striatum with dopaminergic denervation, a large part of the L‐DOPA‐derived extracellular DA is also derived from a vesicular pool that is released by an exocytosis mechanism.