Publication
Title
Pharmacological characterization of the Haemonchus contortus GABA-gated chloride channel, Hco-UNC-49 : modulation by macrocyclic lactone anthelmintics and a receptor for piperazine
Author
Abstract
Invertebrate ligand-gated chloride channels are well recognized as important targets for several insecticides and anthlemintics. Hco-UNC-49 is a GABA-gated chloride channel from the parasitic nematode Haemonchus contortus and is an orthologue to the neuromuscular receptor (Cel-UNC-49) from the free-living nematode Caenorhabditis elegans. While the receptors from the two nematodes are similar in sequence, they exhibit different sensitivities to GABA which may reflect differences in in vivo function. The aim of the current study was to further characterize the pharmacology of the Hco-UNC-49 receptor by examining its sensitivity to various insecticides and anthelmintics using two-electrode voltage clamp. Specifically, the insecticides fipronil and picrotoxin appear to inhibit the channel in a similar manner. The IC50 of picrotoxin on the homomeric channel was 3.65 ± 0.64 μM and for the heteromeric channel was 134.56 ± 44.12 μM. On the other hand, dieldrin, a well-known insect GABA receptor blocker, had little effect on the UNC-49 channel. The anthelmintics ivermectin and moxidectin both moderately potentiated the activation of Hco-UNC-49 by GABA, while piperazine was able to directly activate both the Hco-UNC-49 homomeric and heteromeric channels with EC50 values of 6.23 ± 0.45 mM and 5.09 ± 0.32 mM, respectively. This piperazine current was reversibly blocked by picrotoxin which demonstrates that the anthelmintic specifically targets Hco-UNC-49. These results demonstrate that Hco-UNC-49 exhibits binding sites for several molecules including piperazine and macrocyclic lactone anthelmintics. In addition, this is the first report of the heterologous expression and subsequent characterization of a receptor for piperazine.
Language
English
Source (journal)
Veterinary parasitology. - Amsterdam
Publication
Amsterdam : 2012
ISSN
0304-4017
DOI
10.1016/J.VETPAR.2011.10.006
Volume/pages
185 :2-4 (2012) , p. 201-209
ISI
000302839700022
Pubmed ID
22075040
Full text (Publisher's DOI)
Full text (publisher's version - intranet only)
UAntwerpen
Publication type
Subject
External links
Web of Science
Record
Identifier
Creation 10.10.2023
Last edited 11.10.2023
To cite this reference