The constitution of pseudo-muscarine ("synthetic muscarine") / by A.J. Ewins.
- Ewins, Arthur James.
- Date:
- [1914?]
Licence: In copyright
Credit: The constitution of pseudo-muscarine ("synthetic muscarine") / by A.J. Ewins. Source: Wellcome Collection.
4/12 page 210
![differences being that the synthetic base showed a powerful curare-like action which the natural base does not possess, and that the synthetic base did not constrict the mammalian pupil whereas natural muscarine does. The problem was still further complicated by the fact that the aldehyde corresponding to choline, the so-called “ betaine aldehyde ” which was first synthesised by Berlinerblau [1884] and later by E. Fischer [1893] (who proved its constitution by oxidising it to betaine), was found to differ considerably in its action from both the natural and “ synthetic ” muscarines. The problem was later re-investigated by Nothnagel [1894]. He obtained both natural and “ synthetic ” muscarine ; the former from Amanita muscaria, the latter by Schmiedeberg and Harnack’s method from choline. He too stated that so far as could be judged from the small amount of material available, the natural muscarine was chemically identical with the synthetic base, and confirmed Schmiedeberg and Harnack’s formula for the latter. He also repeated and confirmed Berlinerblau’s work. The physiological action of these bases was examined by Hans Meyer who confirmed Boehm’s observa¬ tions with regard to synthetic and natural muscarine and in addition pointed out further differences in their action. Briefly then it appeared that there were two chemically indistinguishable bases which possessed different physiological actions and for this no satis¬ factory explanation has as yet been put forward. Recently during an investigation into the nature of a muscarine-like base which is present in extracts of ergot, and was found to be acetyl-choline, as already described [Ewins, 1914], I had occasion to prepare some pseudo¬ muscarine for purposes of comparison and it occurred to me that, in view of the facts detailed above, confirmation of the constitution of this base was desirable, and that further examination might throw some light on the general problem. The preparation of the base gave no difficulty and a pure crystalline platinichloride was obtained, the base from which showed all the characteristic physiological effects1 of synthetic muscarine as described by Boehm [1885], Hans Meyer [v. Nothnagel, 1894] and Honda [1911]. The formula assigned by Schmiedeberg and Harnack to their platini¬ chloride and confirmed by Nothnagel was as follows: [Cl N (CH3)3CH2. CH (OH)2]2 PtCl4.2H20. The salt thus contained two molecules of water of crystallisation. It is to be noted, however, that these were not completely removed, except by heating to a temperature of 130-135°. 1 The physiological experiments involved in this investigation were in all cases carried out by Dr H. H. Dale.](https://iiif.wellcomecollection.org/image/b30620909_0004.jp2/full/800%2C/0/default.jpg)
