The action of some isoquinoline derivatives / by P.P. Laidlaw.
- Laidlaw, Patrick Playfair, 1881-1940.
- Date:
- [1911?]
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.
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![mO-l’HKMlCAJ. JOURNAL iiitiict miimiiial. as friveii by various authors (Falk, Marfori, von liunjre. Ronsso, etc.) aio inucli tlie saiue as the above. A few experiments were made witli cotarnine, and essentially the same clinical picture was seen with toxic doses; but cotarnine appeared to be le.ss toxic. Doses of lot) m<,nn. of cotarnine were found to be fatal for guinea-pigs of about TOO grams, but 100 mgm. doses were not. The heart beat also did not appear to be (|uite as well maintained during the later stages of poisoning by this substance. ()n the central nervous system these three alkaloids exert a depressant action, and cause death by respiratorv failure. 1 he failure of the respiration is of central origin, since there is no evidence of any well-marked peripheral action by these three substances (see later). 1 he vasruJnr xifstem. A series of exjieriments were performed with a view to determine the action of 0 :7-dimethoxy 2-methyl 3;4-dihydro- i.so-{juinolinium chloride on the vascular system. These were for the most part performed upon pithed cats, but a number were also performed upon anaestheti.sed animals. Chloroform, ether, paraldehyde and ether, and urethane, were the anaesthetics employed. The main features of the results obtained upon cats were confirmed upon rabbits. When a dose of 10 mgm. of the new alkaloid is injected into the l)lood stream of a ])ithed cat, and the blood pressure is recorded by a mercury manometer from the carotid artery, there is noticeable a rise of l)lood pre.ssure. At the same time as the blood pressure rises the heart beat becomes slower and the o.scil hit ions of the mercury manometer increase in size. With larger doses, 20 mgm., the .same action is ob.servable, but both are slightly more marked. Considerable variation is met with in the height of the rise of blood jiressure. It is never very large, and rarely exceeds 40 mm. of mercury with doses of 10-20 mgm. Fig. 1 shows one of the smaller ri.ses of blood pressure; others will be seen in other figures. The rise in blood pre.ssure is the result of two factors—(1) slight vaso constriction, (2) increased cardiac output. The rise of blood pressure being partly accounted for by increased cardiac activity, and being never very large, it will be obvious that the vaso-coustriction must be slight. It was found, indeed, that the vaso- constriction was not easy to demonstrate. Inspection of the viscera during the administration of a full dose of the alkaloid appeared to show that .some constriction of the arterioles occurred, but it was never incontestable except in the case of the highly vascular organs, such as the uterus of a virgin rabbit. In this instance](https://iiif.wellcomecollection.org/image/b22432838_0016.jp2/full/800%2C/0/default.jpg)
