Effects of putative neurotransmitters on the motor activity of Spirometra mansonoides

5-Hydroxytryptamine (5-HT), epinephrine, and dopamine strongly stimulated the motor activity of larval Spirometra mansonoides. By contrast, a cholinomimetic agent, arecoline, paralyzed the worms. There was some pharmacological specificity among the agonists but not with various antagonists. Acetylcholinesterase activity was present in both larval and adult Spirometra.