title: Endocytosis promotes rapid dopaminergic signaling.
abstract: D(1) dopamine receptors are primary mediators of dopaminergic signaling in the CNS. These receptors internalize rapidly following agonist-induced activation, but the functional significance of this process is unknown. We investigated D(1) receptor endocytosis and signaling in HEK293 cells and cultured striatal neurons using real-time fluorescence imaging and cAMP biosensor technology. Agonist-induced activation of D(1) receptors promoted endocytosis of receptors with a time course overlapping that of acute cAMP accumulation. Inhibiting receptor endocytosis blunted acute D(1) receptor-mediated signaling in both dissociated cells and striatal slice preparations. Although endocytic inhibition markedly attenuated acute cAMP accumulation, inhibiting the subsequent recycling of receptors had no effect. Further, D(1) receptors localized in close proximity to endomembrane-associated trimeric G protein and adenylyl cyclase immediately after endocytosis. Together, these results suggest a previously unanticipated role of endocytosis, and the early endocytic pathway, in supporting rapid dopaminergic neurotransmission.
authors.affiliation: Department of Psychiatry and Department of Cellular and Molecular Pharmacology, University of California at San Francisco, San Francisco, CA 94158, USA.
authors.forename: Sarah J
authors.initials: SJ
authors.lastname: Kotowski
authors.forename: F Woodward
authors.initials: FW
authors.lastname: Hopf
authors.forename: Taban
authors.initials: T
authors.lastname: Seif
authors.forename: Antonello
authors.initials: A
authors.lastname: Bonci
authors.forename: Mark
authors.initials: M
authors.lastname: von Zastrow
mesh_terms: D000200:Action Potentials / Q000187:drug effects / Q000235:genetics; D000262:Adenylyl Cyclases / Q000494:pharmacology; D000818:Animals; D001552:Benzazepines / Q000494:pharmacology; D002352:Carrier Proteins / Q000037:antagonists & inhibitors / Q000235:genetics; D002478:Cells, Cultured; D003342:Corpus Striatum / Q000166:cytology; D000242:Cyclic AMP / Q000494:pharmacology; D004298:Dopamine / Q000378:metabolism* / Q000494:pharmacology; D018491:Dopamine Agonists / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004622:Embryo, Mammalian; D004705:Endocytosis / Q000187:drug effects / Q000502:physiology*; D005434:Flow Cytometry / Q000379:methods; D020662:Guanine Nucleotide Exchange Factors / Q000378:metabolism; D006801:Humans; D006835:Hydrazones / Q000494:pharmacology; D008856:Microscopy, Fluorescence / Q000379:methods; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D021381:Protein Transport / Q000187:drug effects; D034741:RNA, Small Interfering / Q000494:pharmacology; D051381:Rats; D017447:Receptors, Dopamine D1 / Q000235:genetics; D015398:Signal Transduction / Q000502:physiology*; D013997:Time Factors; D014162:Transfection / Q000379:methods
chemical_list: D001552:Benzazepines; D002352:Carrier Proteins; D018491:Dopamine Agonists; C406447:EHD3 protein, human; D020662:Guanine Nucleotide Exchange Factors; D006835:Hydrazones; C511794:N'-(3,4-dihydroxybenzylidene)-3-hydroxy-2-naphthahydrazide; C116122:RAPGEF3 protein, human; D034741:RNA, Small Interfering; D017447:Receptors, Dopamine D1; C067113:SK&F 81297; D000242:Cyclic AMP; D000262:Adenylyl Cyclases; D004298:Dopamine