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Effects of Cannabinoids on Dopamine Release in the Corpus Striatum and the Nucleus Accumbens In Vitro
Author(s) -
Szabo Bela,
Müller Tobias,
Koch Helga
Publication year - 1999
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.1471-4159.1999.0731084.x
Subject(s) - nucleus accumbens , dopamine , chemistry , dopaminergic , neuroscience , striatum , cannabinoid , dopamine receptor d1 , quinpirole , ventral tegmental area , substantia nigra , dopamine receptor , cannabinoid receptor , agonist , medicine , endocrinology , receptor , biology , biochemistry
: Cannabinoid receptors are widely distributed in the nuclei of the extrapyramidal motor and mesolimbic reward systems ; their exact functions are, however, not known. The aim of the present study was to characterize the effects of cannabinoids on the electrically evoked release of endogenous dopamine in the corpus striatum and the nucleus accumbens. In rat brain slices dopamine release elicited by single electrical pulses was determined by fast cyclic voltammetry. Dopamine release was markedly inhibited by the OP 2 opioid receptor agonist U‐50488 and the D 2 /D 3 dopamine receptor agonist quinpirole, indicating that our method is suitable for studying presynaptic modulation of dopamine release. In contrast, the CB 1 /CB 2 cannabinoid receptor agonists WIN55212‐2 (10 ‐6 M ) and CP55940 (10 ‐6 ‐10 ‐5 M ) and the CB 1 cannabinoid receptor antagonist SR141716A (10 ‐6 M ) had no effect on the electrically evoked dopamine release in the corpus striatum and the nucleus accumbens. The lack of a presynaptic effect on terminals of nigrostriatal and mesolimbic dopaminergic neurons is in accord with the anatomical distribution of cannabinoid receptors : The perikarya of these neurons in the substantia nigra and the ventral tegmental area do not synthesize mRNA, and hence protein, for CB 1 and CB 2 cannabinoid receptors. It is therefore unlikely that presynaptic modulation of dopamine release in the corpus striatum and the nucleus accumbens plays a role in the extrapyramidal motor and rewarding effects of cannabinoids.