Effect of Triton X-100 on tegument and muscle in Schistosoma mansoni.

Short periods of in vitro incubation of Schistosoma mansoni with low concentrations of the nonionic detergent Triton X-100 caused marked changes in the physiological and morphological status of the parasite. Less than 15 min of exposure to 1 mM Triton at 37 C led to irreversible destruction of the tegument, relaxation and depolarization of the muscle, and loss of response to electrical stimulation, to 60 mM K+-HBS, or to 10(-6) M praziquantel. A 5-min incubation in 100 microM Triton X-100 caused no gross structural damage, changes in tegumental or E2 electrical potential, or decrease in response to praziquantel, but markedly inhibited the ability of 60 mM K+-HBS or electrical stimulation to cause muscle contraction. Radioactive calcium influx measurements indicated that a 5-min exposure to 100 microM Triton X-100 may be uncoupling membrane depolarization from development of muscle tension by interfering pharmacologically with calcium channels. Longer incubations (15 min) in the presence of 100 microM Triton X-100 caused transitional physiological changes suggesting that the mode of action of the detergent was passing from a specific, pharmacological mode to a nonspecific disruptive action.