[Beta]-iminazolylethylamine : a depressor constituent of intestinal mucosa / by G. Barger and H.H. Dale.

  • Barger, George, 1878-1939.
Date:
[1911]
Catalogue details

Licence: In copyright

Credit: [Beta]-iminazolylethylamine : a depressor constituent of intestinal mucosa / by G. Barger and H.H. Dale. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

    4/10 (page 500)
    P. P. Laidlaw1, described the action of /S-iminazolylethylamine and drew attention to the fact that it produced all the effects attributed to “ vaso-dilatin ” with the exception of that on the coagulability of the blood. Further experiment, of which the details will be published later, has confirmed the absence of effect on coagulability, but has revealed a further point of similarity in that /S-iminazolylethylamine increases the flow of lymph from the thoracic duct. Since the purest preparation of “ vaso-dilatin ” yet obtained by the Lemberg laboratory produced, in a dose of 3 6 mgms., a fall of blood-pressure which, so far as Modrakowski’s3 experiments are comparable with our own, would correspond to a much smaller dose of iminazolylethylamine, it seemed desirable to investigate the possibility that the latter substance might be a constituent of “vaso-dilatin.” As in Dale and Laidlaw’s paper we shall, for the sake of brevity, refer to the base as /3-I. Having found that all the extracts and preparations in question produce the characteristic action on the non-pregnant uterus of the cat and guinea-pig, we used the response of the latter as a physiological indicator in tracing the active substance. Since intestinal extracts were especially active in producing the vaso-dilator fall of blood-pressure and contraction of the guinea-pig’s uterus, we took such an extract for investigation. We were not immediately concerned with the specific effect of secretin on pancreatic secretion, but with the associated depressor action. The highly depressant extract of ox-gut with its comparatively small effect on the flow of pancreatic juice, was, therefore, quite suitable for our purpose. Small intestines of the ox, fresh from the slaughter-house, were washed through by a stream of water and placed in cold storage at — 2° C. Next day the mucous membrane was scraped off and ground with sand. Enough dilute hydrochloric acid was added to make the concentration of the semi-fluid mass equal to 0T °/0 HC1. It was boiled, nearly neutralised, and filtered at the pump. In this way, 750 c.c. of extract were obtained from each kilo of “ scrapings.” The extract was concentrated, and 20°/o tannin was added to it until the precipitate flocculated. The solution then filtered clear; with excess of tannin this was not so. The filtrate was further treated according to Kutscher’s method and the silver precipitate produced by adding excess of baryta in the presence of silver nitrate was^ollected (precipitates Ag. II and Ag. III). From this the bases were regenerated and extracted with hot absolute alcohol. On evaporation of the alcohol 1 This Journal, xli. p. 318. 1910. 3 Loc. cit.