The physiological action of choline and neurine / F.W. Mott.

  • Frederick Walker Mott
Date:
1899
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Licence: Public Domain Mark

Credit: The physiological action of choline and neurine / F.W. Mott. Source: Wellcome Collection.

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

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    of 0‘06 gram causes arrest of the respiration, which, however, is resumed after a time. There can be very little doubt that the choline described by these two investi- gators consisted very largely of neurine. V. Cervello* * * § made a more complete investigation of the two alkaloids; he recognised that the neurine of commerce contains both substances; he investigated the action of each ; and states that both act in precisely the same way, but that neurine is the more powerful of the two. Using commercial neurine, he found that the fatal dose in frogs was 3 or 4 milli- grams ; the most marked symptoms are dilatation of the pupil and paralysis. In rabbits the fatal dose was 5 centigrams injected subcutaneously ; it produces saliva- tion and gradual paralysis. In dogs weighing 6 kilograms, 30 centigrams was the fatal dose. In Mammals death is due to cessation of the respiration, which is caused by the curare-like action of the drug on the voluntary muscles.! In dogs the intravascular injection of 0‘02 gram causes the heart to become slower and irregular, a rise of blood-pressure, and an increase in the depth and rate of respiration. After several injections artificial respiration is necessary to keep the animal alive. Previous cutting of both pneumogastric nerves does not modify this action. Cervello’s general conclusion is that the chief effect of the poison is on the respiration, and that the vascular changes are mainly secondary to this. He, how- ever, found on the frog’s heart (both in situ and isolated) that the poison acts like muscarine, and the stoppage of the heart so produced is antagonised by atropine. Moreover, he states that the antagonism, as in the case of muscarine and atropine, is a unilateral one. From experiments on salivary secretion he also concludes that neurine and atropine are antagonistic in their action on the glandular system. He states that neurine is eliminated from the body by the urine. In the course of an investigation on the effects of suprarenal extract, Schafer and Oliver| investigated the action of neurine on arterial blood-pressure, since some observers were inclined to believe that the active princqffe in suprarenal extract is neurine. They describe a preliminary fall of pressure, and a subsequent rise. This is what we have found, though in most cases the rise has been greater than in the tracing reproduced by Schafer and Oliver in their paper. Schafer and Moore,§ in a paper on the contractibility of the sjfieen, found that an extract of dried brain substance made with boiling water or saline solution, pro- duces a fall of blood-pressure and great increase in the extent of the rhythmic splenic movements. From the similar result which we have found to follow the * ‘Arch. Ital. de Biol.,’ 1886, vol. 7, pp. 172 and 232. t MORIGGIA (‘Atti della R. Acad, dei Lineei,’ ser. 3; Trans., 8, livr. 10, p. 232) on insufficient grounds denies this curare-like action. \ ‘ Journ. of Physiology,’ 1895, vol. 18, p. 266. § Ibid, 1896, vol. 20, p. 26.
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