Characterization of levamisole binding sites in Trichinella spiralis.
Characterization of the levamisole receptor was performed with total extracts of Trichinella spiralis muscle larvae using binding assays with tritiated levamisole ([3H]LEV, 291 GBq/mmol). We detected a specific [3H]LEV binding activity with a dissociation constant (Kd) of 4.76 microM and a receptor density (Bmax) of 2.14 pmol/mg of protein. In inhibition studies, only dimethylphenylpiperazinium iodide (DMPP) and hexamethonium were found to be competitive inhibitors of the [3H]LEV binding with an inhibition constant (Ki) of 31.04 and 4.43 microM, respectively, whereas d-tubocurarine and alpha-bungarotoxine had no effect on [3H]LEV binding activity, and procaine and atropine potentiated the [3H]LEV-receptor binding. All these data support the idea that levamisole acts as a cholinergic agonist in T. spiralis.
Parasitology and Microbiology Department, Faculty of Pharmacy, University of Alcalá, Alcalá de Henares, Madrid, Spain. mpmjmg@microb.alcala.es
A
A
Jiménez-González
R M
RM
Ros-Moreno
M J
MJ
Moreno-Guzmán
F
F
Rodríguez-Caabeiro
D000818:Animals; D000969:Antinematodal Agents / Q000493:pharmacokinetics*; D001665:Binding Sites; D001667:Binding, Competitive; D004246:Dimethylphenylpiperazinium Iodide / Q000494:pharmacology; D007700:Kinetics; D007978:Levamisole / Q000493:pharmacokinetics*; D017160:Trichinella spiralis / Q000378:metabolism*; D014316:Tritium
D000969:Antinematodal Agents; D014316:Tritium; D007978:Levamisole; D004246:Dimethylphenylpiperazinium Iodide