. The preparation of a muscle strip of Ascaris lumbricoides for the study of the effect of drugs in vitro is described. . Stimulant drugs which are classified as nicotine‐like in mammalian pharmacology increased the isometric tension of this preparation. These drugs were, in descending order of potency: dimethylphenylpiperazinium, nicotine, acetylcholine, carbachol, decamethonium and pyridine‐2‐aldoxime methiodide. . Muscarine‐like drugs (oxotremorine, methacholine, pilocarpine) had no activity. . Potassium and barium ions stimulated the tissue, while the anti‐cholin‐esterases, dichlorvos and eserine, increased the resting tension of the preparation and potentiated the responses to acetylcholine. . Adrenaline neither stimulated the tissue nor affected the responses to nicotine‐like drugs. . The relative potency of several blocking agents which antagonize the responses to nicotine‐like drugs was assayed. These blocking agents were, in descending order of potency: mecamylamine, (+)‐tubocurarine, hexamethonium, atropine and piperazine. Acetylcholine, dimethylphenylpiperazinium and pyridine‐2‐aldoxime methiodide apparently act on a common receptor, for each blocking agent had a similar molar inhibitory concentration against these stimulants. . It is concluded that the cholinoceptor in muscle preparations of Ascaris lumbricoides is pharmacologically similar to that of the mammalian autonomic ganglion.

No abstract

No abstract

Using an earlier model of the favoured orientation of binding functions of angiotensin converting enzyme (ACE) inhibitors, it has been possible to postulate a new, 7,6‐bicyclic system, based on hexahydropyridazine, which might be expected to have high potency. Some members of this system which have been synthesised have been shown to be very active ACE inhibitors, in vitro and in vivo.