The significance of the supra-renal capsules in the action of certain alkaloids / by H.H. Dale and P.P. Laidlaw.

  • Henry Hallett Dale
Date:
[1912]
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Licence: Public Domain Mark

Credit: The significance of the supra-renal capsules in the action of certain alkaloids / by H.H. Dale and P.P. Laidlaw. Source: Wellcome Collection.

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    the methods of Can non and de la Paz1, and of Hoskins2, with isolated portions of rabbit’s intestine, or our own method with the isolated uterus of the non-pregnant cat. Hirudin blood has, indeed, a small degree of this motor action on plain muscle, but far less than fresh serum. We find the non-pregnant cat’s isolated uterus a highly sensitive indicator of adrenine action. The effect, being inhibition, cannot be confused with that of other substances in the blood or serum which increase the tone of plain muscle. It shares this advantage with the rabbit’s intestine, used by Cannon and his co-workers and by Hoskins. It has, in addition, the advantage, that varying submaximal doses of adrenine cause relaxation of varying rate and completeness ; so that by finding a dose of adrenine which produces, on a given uterus, relaxation of the same speed and depth as a certain dose of blood; one can form a tolerably accurate estimate of the proportion of adrenine in the blood. As a general method it has the disadvantage that non-pregnant female cats are at times difficult to obtain, and that not all of them have uteri of the desirable high sensitiveness to adrenine. For our present investiga¬ tion, however, it was the obvious choice. We suspended a horn of the uterus in. warm oxygenated Ringer’s solution in the usual manner, using a small cylindrical bath holding 20 c.c., with the usual arrangements for changing the Ringer’s solution without disturbing the organ or interrupting the record seriously. Addition to the bath of jugular blood, in any volume, if it produced any effect at all, caused only a small increase of tone. Normal blood from the supra-renal veins, on the other hand, always showed evidence of containing adrenine. The proportion present varied with the rate of outflow, being considerably greater when the flow was slow (pure supra-renal blood) than when it was rapid (small tributary veins discovered post-mortem). We performed five experiments in all, using a loop of rabbit’s intestine as indicator in one. In every experiment there was a markedly supernormal proportion of adrenine in blood from the supra-renal vein collected after an injection of pilocarpine. In most cases, however, the rate of flow was much slower, owing to the cardiac inhibition. Allowance had to be made for this; for, if it were assumed that the supra-renal glands formed and secreted adrenine at constant rate, the mere retardation of the circulation would increase the content of the venous blood in inverse proportion to the rate of outflow. It was 1 Amer. Journ. of Physiol, xxviii. p. 64. 1911. 2 Journ. of Pharm, and exper. Therap. hi. p. 93. 1911.
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