title: Dopamine D3 (auto) receptors inhibit dopamine release in the frontal cortex of freely moving rats in vivo.
abstract: In freely moving rats, the novel, selective dopamine (DA) D3 receptor agonist PD 128,907 dose-dependently [effective dose (ED25) = 0.07 mg/kg, s.c.] reduced dialysate levels of DA in the frontal cortex, a structure innervated by the ventral tegmental area (VTA). This action of PD 128,907 (0.16 mg/kg, s.c.) was abolished by a selective DA D3 receptor antagonist S 14297 (1.25 mg/kg, s.c.), which alone did not modify levels of DA. In contrast to S 14297, its inactive distomer, S 17777, did not modify the actions of PD 128,907. In addition, PD 128,907 dose-dependently and potently inhibited the firing rate of VTA-localized neurons in anesthetized rats (ED50 = 0.001 mg/kg, i.v.). S 14297, but not S 17777, completely reversed the actions of PD 128,907 (0.005 mg/kg, i.v.) with a 50% inhibitory dose of 0.03 mg/kg, i.v. and did not itself significantly modify the firing rate. In conclusion, these data provide the first direct evidence that DA D3 (auto) receptors modulate (inhibit) the release of DA in the frontal cortex.
authors.affiliation: Psychopharmacology Department, Centre de Recherches de Croissy, Croissy-sur-Seine, France.
authors.forename: A
authors.initials: A
authors.lastname: Gobert
authors.forename: F
authors.initials: F
authors.lastname: Lejeune
authors.forename: J M
authors.initials: JM
authors.lastname: Rivet
authors.forename: L
authors.initials: L
authors.lastname: Cistarelli
authors.forename: M J
authors.initials: MJ
authors.lastname: Millan
mesh_terms: D015081:2-Naphthylamine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001578:Benzopyrans / Q000494:pharmacology; D004298:Dopamine / Q000378:metabolism*; D018491:Dopamine Agonists / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004594:Electrophysiology; D005625:Frontal Lobe / Q000378:metabolism*; D005663:Furans / Q000494:pharmacology; D008297:Male; D017551:Microdialysis; D010078:Oxazines / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D017448:Receptors, Dopamine D2 / Q000502:physiology*; D050637:Receptors, Dopamine D3; D013681:Tegmentum Mesencephali / Q000187:drug effects / Q000502:physiology
chemical_list: D001578:Benzopyrans; D018491:Dopamine Agonists; D018492:Dopamine Antagonists; C493595:Drd3 protein, rat; D005663:Furans; D010078:Oxazines; D017448:Receptors, Dopamine D2; D050637:Receptors, Dopamine D3; C062458:3,4,4a,10b-tetrahydro-4-propyl-2H,5H-(1)benzopyrano(4,3-b)-1,4-oxazin-9-ol; C090812:7-(N,N-dipropylamino)-5,6,7,8-tetrahydronaphtho(2,3-b)dihydro-2,3-furan; D015081:2-Naphthylamine; D004298:Dopamine