HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Summary Full Text Full Text (PDF) All Versions of this Article: fj.06-6264fjev1 20/14/2606    most recent Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Qian, H. Articles by Robertson, A. P. Search for Related Content PubMed PubMed Citation Articles by Qian, H. Articles by Robertson, A. P.

Pharmacology of N-, L-, and B-subtypes of nematode nAChR resolved at the single-channel level in Ascaris suum

Department of Biomedical Sciences, Iowa State University, Ames, Iowa, USA

²Correspondence: Department of Biomedical Sciences, #2008, College of Veterinary Medicine, Iowa State University, Ames, Iowa 50011-1250. E-mail: rjmartin{at}iastate.edu

ABSTRACT

Pharmacological experiments on Ascaris suum have demonstrated the presence of three (N-, L-, and B-) subtypes of cholinergic receptor mediating contraction of body wall muscle in parasitic nematodes (1) . In the present study, these ionotropic acetylcholine (ACh) receptors (nAChRs) were activated by levamisole and bephenium under patch-clamp conditions and competitively antagonized by paraherquamide and 2-desoxoparaherquamide. A number of recordings exhibited three separate current amplitude levels, indicating the presence of small, intermediate, and large conductance subtypes of receptor. The mean conductance of the small conductance subtype, G₂₅, was 22 ± 1 pS; the intermediate conductance channel, G₃₅, was 33 ± 1 pS; and the large conductance channel, G₄₅, was 45 ± 1 pS. The small channel was not antagonized significantly by paraherquamide and was identified as the N-subtype. The intermediate channel was preferentially activated by levamisole rather than bephenium and antagonized by paraherquamide: the intermediate channel was identified as the L-subtype. The large conductance channel was preferentially activated by bephenium, antagonized more by 2-desoxoparaherquamde than by paraherquamide and was identified as the B-subtype. These observations reveal that the three channel subtypes have different selectivity for cholinergic anthelmintics. The different selectivity of these compounds should be considered when dealing with drug resistant infections.—Qian, H., Martin, R. J., and Robertson, A. P. Pharmacology of N-, L-, and B-subtypes of nematode nAChR resolved at the single-chain level in Ascaris Suum.

This article has been cited by other articles:

				H. Qian, A. P. Robertson, J. A. Powell-Coffman, and R. J. Martin Levamisole resistance resolved at the single-channel level in Caenorhabditis elegans FASEB J, September 1, 2008; 22(9): 3247 - 3254. [Abstract] [Full Text] [PDF]

				H. A. Aloysius, M. V. S. Elipe, B. H. Arison, T. D. Faidley, B. F. Michael, T. A. Blizzard, D. R. Thompson, W. L. Shoop, and R. A. Tschirret-Guth Comparative Disposition and Metabolism of Paraherquamide in Sheep, Gerbils, and Dogs Drug Metab. Dispos., August 1, 2008; 36(8): 1659 - 1669. [Abstract] [Full Text] [PDF]