Abstract
Dihydroergotamine and methysergide have been found to alter motility in Schistosoma mansoni. Both agents have a stimulatory effect at some concentrations and a depressant effect at others. Inhibition is best shown when worms are maximally stimulated by means of serotonin. Stimulation by methysergide is very weak, but dihydroergotamine produces significant increases in motility rates. The pattern of response to dihydroergotamine deviates from a simple partial agonist model in a way that suggests that receptor desensitization occurs. Measurements of the effects on lactate production of methysergide were also made. These suggest that in schistosomes motility and lactate production are directly coupled. The simple nervous system of a schistosome has features which may make it a useful model for the study of other drugs. The nervous system may also be an effective point of attack for antischistosomal agents.
Footnotes
- Received May 21, 1973.
- Accepted November 14, 1973.
- © 1974 by The Williams & Wilkins Co.
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