Effects of nonimmobilizers and halothane on Caenorhabditis elegans

We studied the effects of two nonimmobilizers, a transitional compound, and halothane on the nematode, Caenorhabditis elegans, by using reversible imm obility as an end point. By themselves, the nonimmobilizers did not immobil ize any of the four strains of animals tested. Toluene appears to be a tran sitional compound for all strains tested. The additive effects of the nonim mobilizers with halothane were also studied. Similar to results seen in stu dies of mice, the nonimmobilizers were antagonistic to halothane in the wil d type nematode. However, the nonimmobilizers did not affect the 50% effect ive concentrations of halothane for two other mutant strains. For halothane , the slopes of the dose response curves were smaller in more sensitive str ains compared with the wild type. As in mammals, nonimmobilizers antagonize the effects of halothane on the nematode, C. elegans. The variation in slo pes in the response to halothane in different strains is consistent with mu ltiple sites of action. These results support the use of C, elegans as a mo del for the study of anesthetics.