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Stimulation of group I mGlu receptors in the ventrotegmental area enhances extracellular dopamine in the rat medial prefrontal cortex
Author(s) -
Renoldi G.,
Calcagno E.,
Borsini F.,
Invernizzi R. W.
Publication year - 2007
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.1471-4159.2006.04317.x
Subject(s) - dopamine , agonist , metabotropic receptor , microdialysis , prefrontal cortex , receptor , chemistry , stimulation , glutamate receptor , extracellular , metabotropic glutamate receptor , medicine , neuroscience , endocrinology , pharmacology , biology , biochemistry , cognition
Group I mGlu receptors have been implicated in the control of brain dopamine release. However, the receptor subtype involved and the precise site of action have not been determined. In this study we show that (R,S)3,5‐dihydroxyphenylglycine (DHPG; 6 and 60 nmol ICV), a selective group I mGlu receptor agonist, raised extracellular dopamine respectively by 176% and 243% of basal values in the medial prefrontal cortex as assessed by in vivo microdialysis in conscious rats. (R,S)2‐chloro‐5‐hydroxyphenylglycine (60 nmol ICV), a selective mGlu5 receptor agonist, raised extracellular dopamine by 396% of basal values. Intra‐VTA DHPG (0.6–6 nmol) mimicked ICV injection whereas intracortical infusion (1–1000 µmol/L) had no effect. DHPG‐induced rise of extracellular dopamine was reversed by tetrodotoxin and by the selective mGlu1 and mGlu5 receptor antagonists 7(hydroxyimino)cyclopropa[b]chromen‐1a‐carboxylate (CPCCOEt) and 2‐methyl‐6‐(phenylethynyl)pyridine (MPEP) either ICV or into the ventrotegmental area (VTA), suggesting that neuronal release and both mGlu1 and mGlu5 receptors were involved. These results support the existence of functional mGlu1 and mGlu5 receptors in the VTA regulating the release of dopamine in the medial prefrontal cortex.