title: Comparative pharmacological characterization of D1-like dopamine receptors from Anopheles gambiae, Aedes aegypti and Culex quinquefasciatus suggests pleiotropic signaling in mosquito vector lineages.
abstract: BACKGROUND
  Small molecule antagonists of mosquito dopamine receptors (DARs) are under investigation as a new class of vector-selective insecticides. Antagonists that inhibit the D1-like DARs AaDOP2 and CqDOP2 from the mosquitoes Aedes aegypti L. and Culex quinquefasciatus Say, respectively, also cause larval mortality in bioassays. Here, we report on the orthologous DAR, AgDOP2, from the malaria mosquito Anopheles gambiae Giles that was cloned and pharmacologically characterized in HEK293 cells. Larval bioassays were then conducted to examine the potential of DAR antagonist insecticides against Anopheles vectors.
  
  
  RESULTS
  Previous in vitro cAMP accumulation assays demonstrated Gαs coupling for AaDOP2 and CqDOP2 and dose-dependent inhibition by DAR antagonists. We observed a negligible response of AgDOP2 in the cAMP assay, which prompted an investigation of alternative coupling for mosquito DARs. In an in vitro IP-One Gαq second messenger assay of calcium signaling, dopamine stimulation increased IP1 accumulation in AaDOP2-, CqDOP2- and AgDOP2-expressing cells, and DAR antagonists inhibited IP1 signaling in a dose-dependent manner. In larval bioassays, DAR antagonists caused considerable mortality of An. gambiae larvae within 24 h post-exposure.
  
  
  CONCLUSIONS
  In vitro data reveal pleiotropic coupling of AaDOP2 and CqDOP2 to Gαq and Gαs. In contrast, AgDOP2 appeared to selectively couple to Gαq signaling. In vitro antagonist studies revealed general conservation in pharmacology between mosquito DARs. In vivo data suggest potential for DAR antagonist insecticides against An. gambiae. Sequence conservation among the DOP2 receptors from 15 Anopheles species indicates utility of antagonists to control residual malaria transmission. AgDOP2 Gαq-dependent signaling could be exploited for An. gambiae control via pathway specific antagonists.
authors.affiliation: Department of Entomology, Purdue University, 901 W. State St., West Lafayette, IN, 47907-2089, USA. hillca@purdue.edu.
authors.forename: Catherine A
authors.initials: CA
authors.lastname: Hill
authors.affiliation: Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 575 Stadium Mall Drive, West Lafayette, IN, 47907-2091, USA.
authors.forename: Trevor
authors.initials: T
authors.lastname: Doyle
authors.affiliation: Department of Entomology, Purdue University, 901 W. State St., West Lafayette, IN, 47907-2089, USA.|Present address: Department of Agriculture, Nutrition, and Veterinary Science, University of Nevada, Reno, NV, 89557, USA.
authors.forename: Andrew B
authors.initials: AB
authors.lastname: Nuss
authors.affiliation: Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 575 Stadium Mall Drive, West Lafayette, IN, 47907-2091, USA.
authors.forename: Karin F K
authors.initials: KF
authors.lastname: Ejendal
authors.affiliation: Department of Entomology, Purdue University, 901 W. State St., West Lafayette, IN, 47907-2089, USA.|Present address: Department of Biotechnology, Monsanto Company, Chesterfield, MO, 63017, USA.
authors.forename: Jason M
authors.initials: JM
authors.lastname: Meyer
authors.affiliation: Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 575 Stadium Mall Drive, West Lafayette, IN, 47907-2091, USA.
authors.forename: Val J
authors.initials: VJ
authors.lastname: Watts
mesh_terms: D000330:Aedes / Q000502:physiology*; D000818:Animals; D000852:Anopheles / Q000502:physiology*; D002460:Cell Line; D003001:Cloning, Molecular; D003465:Culex / Q000502:physiology*; D018492:Dopamine Antagonists / Q000378:metabolism*; D004534:Egypt; D005714:Gambia; D006801:Humans; D011954:Receptors, Dopamine / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D018492:Dopamine Antagonists; D011954:Receptors, Dopamine
keywords: Anopheles gambiae; Antagonist; Dopamine; G protein-coupled receptor; Malaria mosquito; Novel insecticide; Signaling