The action of some isoquinoline derivatives / by P.P. Laidlaw.

  • Laidlaw, Patrick Playfair, 1881-1940.
Date:
[1911?]
Catalogue details

Licence: In copyright

Credit: The action of some isoquinoline derivatives / by P.P. Laidlaw. 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.

    18/34 (page 258)
    Jiefore administration of the alkaloid the output in 10 seconds= 1,431 v and afterwards the output in 10 seconds = 1,73G v. In other words, the output per minute is increased by a little more than one-fifth. Fi^s. 7 and 8 show the effect of hydrastinine on the isolated heart and on the cardiac output respectively. Measurements from the cardiometer record show : — Rate before drug .\verage oiitpiit per beat Rate after drug .Average output per beat 42 lioate in 10 seconds. 14 V. 37 beats in 10 seconds. 10 V. Output per 10 seconds before drug ... .‘iS8 v. Output per 10 seconds after drug 703 v. In other words, tire output ])er minute is increased by a little less than one-fifth. In this respeci also hydrastinine has a very similar action to that of the new alkaloid. Cotarnine, on the other hand, does not produce the same effect. The heai't becomes slower, but the output remains the .same, or mav even be diminished (marked decrease in force of heart beat or output per beat is unusual). Fijr. 9 shows a fairly typical result. In this tracing before the administration of the drug the average I'ate of heart per 10 seconds was 32, the average out])ut ])er beat 12 v.—hence output per 10 seconds = 384 v. .\t the maximal etfect of the drug (20 mgm. intravenously, 2^ kilos, cat )— The average rate of heart per 10 .seconds was 29 5. The average output per beat was 11 v. Hence output per 10 .seconds = 324 v. Ill other words, the output from the heart under the influence of cotarnine is diminished by about one-fifth. It is clear that the fall in blood-pressure induced by cotarnine is of cardiac origin. Vaso dilatation may play a part, but if so it must be very slight. The fall of blood-pressure induced by cotarnine preparations is recorded by Heinz^ to be of cardiac origin. Kehrer also attributed the fall to diminished cardiac activity. Neither appears to have demonstrated the point succe.ssfully. however. 'I’he elfects of hydrastinine and cotarnine