“The antagonism of neuroleptics of various groups (chlorpromazine, chlorprothixene, clopenthixol, clozapine, flupenthixol, fluphenazine, haloperidol, levomepromazine, mepazine, perazine, perphenazine, pimozide, prochlorperazine, promazine, spiperone, thiopromazine, thioridazine, trifluperazine, trifluperidol, triflupromazine) towards L-5-hydroxytryptophan (5-HTP ) was assessed on the basis of inhibition of characteristic head-twitches.”