title: Pharmacological and signalling properties of a D2-like dopamine receptor (Dop3) in Tribolium castaneum.
abstract: Dopamine is an important neurotransmitter in the central nervous system of vertebrates and invertebrates. Despite their evolutionary distance, striking parallels exist between deuterostomian and protostomian dopaminergic systems. In both, signalling is achieved via a complement of functionally distinct dopamine receptors. In this study, we investigated the sequence, pharmacology and tissue distribution of a D2-like dopamine receptor from the red flour beetle Tribolium castaneum (TricaDop3) and compared it with related G protein-coupled receptors in other invertebrate species. The TricaDop3 receptor-encoding cDNA shows considerable sequence similarity with members of the Dop3 receptor class. Real time qRT-PCR showed high expression in both the central brain and the optic lobes, consistent with the role of dopamine as neurotransmitter. Activation of TricaDop3 expressed in mammalian cells increased intracellular Ca(2+) signalling and decreased NKH-477 (a forskolin analogue)-stimulated cyclic AMP levels in a dose-dependent manner. We studied the pharmacological profile of the TricaDop3 receptor and demonstrated that the synthetic vertebrate dopamine receptor agonists, 2 - amino- 6,7 - dihydroxy - 1,2,3,4 - tetrahydronaphthalene hydrobromide (6,7-ADTN) and bromocriptine acted as agonists. Methysergide was the most potent of the antagonists tested and showed competitive inhibition in the presence of dopamine. This study offers important information on the Dop3 receptor from Tribolium castaneum that will facilitate functional analyses of dopamine receptors in insects and other invertebrates.
authors.affiliation: Department of Animal Physiology and Neurobiology, Zoological Institute, KU Leuven, Naamsestraat 59, 3000 Leuven, Belgium; Department of Zoology, University of Otago, 340 Great King Street, Dunedin, New Zealand. Electronic address: heleen.verlinden@bio.kuleuven.be.
authors.forename: Heleen
authors.initials: H
authors.lastname: Verlinden
authors.affiliation: Department of Animal Physiology and Neurobiology, Zoological Institute, KU Leuven, Naamsestraat 59, 3000 Leuven, Belgium.
authors.forename: Rut
authors.initials: R
authors.lastname: Vleugels
authors.affiliation: Department of Animal Physiology and Neurobiology, Zoological Institute, KU Leuven, Naamsestraat 59, 3000 Leuven, Belgium.
authors.forename: Rik
authors.initials: R
authors.lastname: Verdonck
authors.affiliation: Department of Zoology, University of Otago, 340 Great King Street, Dunedin, New Zealand.
authors.forename: Elodie
authors.initials: E
authors.lastname: Urlacher
authors.affiliation: Department of Animal Physiology and Neurobiology, Zoological Institute, KU Leuven, Naamsestraat 59, 3000 Leuven, Belgium.
authors.forename: Jozef
authors.initials: J
authors.lastname: Vanden Broeck
authors.affiliation: Department of Zoology, University of Otago, 340 Great King Street, Dunedin, New Zealand.
authors.forename: Alison
authors.initials: A
authors.lastname: Mercer
mesh_terms: D000818:Animals; D016466:CHO Cells; D003412:Cricetulus; D000242:Cyclic AMP / Q000378:metabolism; D018491:Dopamine Agonists / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000494:pharmacology; D057809:HEK293 Cells; D006801:Humans; D008969:Molecular Sequence Data; D060888:Real-Time Polymerase Chain Reaction; D011954:Receptors, Dopamine / Q000032:analysis / Q000378:metabolism*; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism; D020539:Sequence Analysis, Protein; D015398:Signal Transduction; D014231:Tribolium / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism*
chemical_list: D018491:Dopamine Agonists; D018492:Dopamine Antagonists; D011954:Receptors, Dopamine; D043562:Receptors, G-Protein-Coupled; D000242:Cyclic AMP
keywords: Amine; Dopamine; Evolution; G protein-coupled receptor (GPCR); Insect; Pharmacology; Signalling