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Tomosky TK, Bennett JL, Bueding E.
“Tryptaminergic and Dopaminergic Responses of Schistosoma mansoni”.
J.Pharmacol.Exp.Ther.. 1974;190(2):260-71.
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Abstract
The pharmacological manipulation of motor activity of Sichistosoma mansoni was studied. Adult schistosomes were removed from mice veins and placed in 750rse serum with or without added drug. The motor activity (frequency of body contractions)-and body length were noted in response to drug solutions of 10 6 to 10-3 M. Motor activity was enhanced by acute application of 5-hydroxy tryptamine (5-HT), atropine and mecamylamine. The action of these agents was antagonized by BOL, MCE and dihydroergotamine but not by LSD. Incubation with reserpine. chlorimipramine, reserpine and chlorimipramine, protryptyline, d-amphetamine, 4- a-dimethyl-m-tyramine, tryptamine, N-methyl-5-HT and N,N dimethyl 5-HT depleted 5-HT levels and was associated with increased motor activity. The latter was inhibited by BOL and MCE. Depletion of 5-HT in worms by pretreatment with reserpine and chlorimipramine abolished the rise in motor activity except after tryptamine, 5-HT, N-methyl-, and N,N-dimethyl-5-HT. Structure-activity relationships of 5-HT analogs (see below) were studied. Several modifications reduced the compounds potencies but 5 and 6 hydroxylation were the most effective in abolishin motor enhancing effects Incubation of paired males with dopamine (DA), noradrenaline (NE), apomorphine (AP) or adrenaline (E) increased the length of the worms, Clonidine, isoprenaline, octopamine and dibutyryl cyclic AMP did not alter the worms' lengths. At high concentrations, DA and AP produced shortening of the worms. Single and paired males differed in their sensitivity to the effects of neostigmine, carbachol and 5-HT, but not metrifonate, dichlorvos and arecoline. The response of the worms to DA, NE, AP and E was partially antagonised by phenoxybenzamine, butoxamine9 phentolamine, propranolol, pronethaloland, dichloroisoprenaline, but not by dibenamine, yohimbine, practolol or LB-46 (Sandoz). The effects of DA, NE, AP and E were blocked by d'hydroergotamine, d'hydro ergocristine, spiroperidol, haloperidol, pimozide and ergonovine. Male worms from single sex infections differed in their lengthening responses from male-female pairs.
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