Haemonchus contortus: Characterization of a Glutamate Binding Site in Unselected and Ivermectin-Selected Larvae and Adults
Authors: Paiement J.-P.; Prichard R.K.; Ribeiro P.
Source: Experimental Parasitology, Volume 92, Number 1, May 1999 , pp. 32-39(8)
Publisher: Academic Press
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Abstract:
Paiement, J.-P., Prichard, R. K., and Ribeiro, P. 1999. Haemonchus contortus: Characterization of a glutamate binding site in unselected and Ivermectin-selected larvae and adults. Experimental Parasitology92, 32–39. A specific ivermectin-sensitive, glutamate binding site has been identified in the parasitic nematode Haemonchus contortus. Glutamate binding in H. contortus was saturable and occurred in a single class of high-affinity binding sites which appeared to have pharmacological properties different from those of mammalian glutamate receptors. Adult and larval forms of H. contortus had dramatically different glutamate binding kinetics, the larvae showing nearly up to 200-fold higher Bmax values and up to 9-fold increases in Kd values compared to adults. Treatment of adult H. contortus with the anthelmintic, ivermectin, decreased the Bmax value for glutamate binding in the susceptible strain but not in the resistant parasites. Furthermore, selection for ivermectin resistance was associated with a significant increase in Bmax for glutamate binding in adults and a similarly significant increase in glutamate binding affinity in larvae. These results suggest that the H. contortus glutamate binding site identified in this study may be involved in the phenomenon of ivermectin resistance. Copyright 1999 Academic Press.
Language: English
Document Type: Research article
Affiliations: Institute of Parasitology, McGill University, 21 111 Lakeshore Road, Ste-Anne-de-Bellevue, Quebec, H9X 3V9, Canada:
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