title: Characterization of a novel tyramine-gated chloride channel from Haemonchus contortus.
abstract: Tyramine (TA), a trace amine, is becoming accepted as a main stream neurotransmitter in invertebrates. Recent evidence indicates that part of the function of TA in nematodes involves a novel receptor (Cel-LGC-55) from the ligand-gated chloride channel class of ionotropic receptors. However, the role of TA or its receptors in the biology of nematode parasites is limited. Haemonchus contortus is a deadly parasitic worm which causes significant economic burden in the production of small ruminants in many parts of the world. In this study, we have cloned and characterized a novel LGCC from H. contortus which we have named Hco-LGC-55. This receptor subunit is a clear orthologue of Cel-LGC-55 and is able to form a homomeric chloride channel that is gated by tyramine, dopamine and octopamine. Semi-quantitative reverse transcription-polymerase chain reaction (sqRT-PCR) shows that this subunit is expressed in all life-cycle stages of the worm, but appears to have reduced mRNA expression in the adult male.
authors.affiliation: University of Ontario Institute of Technology, Faculty of Science, 2000 Simcoe Street North, Oshawa, ON, L1H 7K4 Canada.
authors.forename: Vijayaraghava T S
authors.initials: VT
authors.lastname: Rao
authors.forename: Michael V
authors.initials: MV
authors.lastname: Accardi
authors.forename: Salma Z
authors.initials: SZ
authors.lastname: Siddiqui
authors.forename: Robin N
authors.initials: RN
authors.lastname: Beech
authors.forename: Roger K
authors.initials: RK
authors.lastname: Prichard
authors.forename: Sean G
authors.initials: SG
authors.lastname: Forrester
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D018118:Chloride Channels / Q000235:genetics / Q000378:metabolism*; D016000:Cluster Analysis; D018509:DNA, Helminth / Q000737:chemistry / Q000235:genetics; D004298:Dopamine / Q000378:metabolism; D005260:Female; D020869:Gene Expression Profiling; D006189:Haemonchus / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009655:Octopamine / Q000378:metabolism; D010802:Phylogeny; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014439:Tyramine / Q000378:metabolism*
chemical_list: D018118:Chloride Channels; D018509:DNA, Helminth; D009655:Octopamine; D004298:Dopamine; D014439:Tyramine