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On the mechanism of d‐amphetamine‐induced changes in glutamate, ascorbic acid and uric acid release in the striatum of freely moving rats
Author(s) -
Miele Maddalena,
Mura Maria A,
Enrico Paolo,
Esposito Giovanni,
Serra Pier A,
Migheli Rossana,
Zangani Danilo,
Miele Egidio,
Desole Maria S
Publication year - 2000
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1038/sj.bjp.0703066
Subject(s) - amphetamine , ascorbic acid , striatum , pharmacology , mechanism (biology) , glutamate receptor , chemistry , uric acid , neuroscience , biochemistry , dopamine , medicine , biology , philosophy , receptor , food science , epistemology
The effects of systemic, intrastriatal or intranigral administration of d‐amphetamine on glutamate, aspartate, ascorbic acid (AA), uric acid, dopamine (DA), dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA) and 5‐hydroxyindoleacetic acid (5‐HIAA) concentrations in dialysates from the striatum of freely‐moving rats were evaluated using microdialysis. d‐Amphetamine (2 mg kg −1 ) given subcutaneously (s.c.) increased DA, AA and uric acid and decreased DOPAC+HVA, glutamate and aspartate dialysate concentrations over a 3 h period after d‐amphetamine. 5‐HIAA concentrations were unaffected. Individual changes in glutamate and AA dialysate concentrations were negatively correlated. d‐Amphetamine (0.2 m M ), given intrastriatally, increased DA and decreased DOPAC+HVA and aspartate dialysate concentrations, but failed to change those of glutamate, AA uric acid or 5‐HIAA, over a 2 h period after d‐amphetamine. Haloperidol (0.1 m M ), given intrastriatally, increased aspartate concentrations without affecting those of glutamate or AA. d‐Amphetamine (0.2 m M ), given intranigrally, increased AA and uric acid dialysate concentrations and decreased those of glutamate, aspartate and DA; DOPAC+HVA and 5‐HIAA concentrations were unaffected. These results suggest that d‐amphetamine‐induced increases in AA and uric acid and decreases in glutamate concentrations are triggered at nigral sites. The changes in aspartate levels may be evoked by at least two mechanisms: striatal (mediated by inhibitory dopaminergic receptors) and nigral (activation of amino acid carrier‐mediated uptake).British Journal of Pharmacology (2000) 129 , 582–588; doi: 10.1038/sj.bjp.0703066