On the action of ergotoxine : with special reference to the existence of sympathetic vasodilators / by H.H. Dale.

  • Dale, Henry Hallett, 1875-1968.
Date:
1913
Catalogue details

Licence: In copyright

Credit: On the action of ergotoxine : with special reference to the existence of sympathetic vasodilators / by 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.

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    splanchnic nerves, after an adequate dose of ergotoxine, will cause a vasodilator fall of pressure, even when the supra-renal glands are extirpated. On the other hand, iD accordance with the general experi- ence, to which I have alluded elsewhere1, that adrenine exaggerates inhibitor sympathetic effects as compared with motor effects, it is to be expected that the vasodilator effect will be relatively smaller, and more difficult to separate from the normally predominant vasoconstrictor effect, with splanchnic stimulation than with adrenine. Exp. 2. (Cf. Fig. 2.) A cat was prepared as before and, in addition, the left supra-renal gland was removed completely, and the left splanch- nic nerves isolated below the diaphragm, cut, and made ready for peripheral stimulation, the exposed viscera being protected by pads Fig. 2. Pithed cat: carotid blood-pressure. Left supra-renal extirpated. Effects of three stimulations of left splanchnic nerves, and of adrenine, after 10 mgms. of ergotoxine. soaked in hot saline solution. An initial control stimulation caused a pure rise of blood-pressure. Two doses, each of 5 mgms. of ergotoxine phosphate, were then given intravenously. The result of three stimula- tions of the left splanchnic nerves, with increasing strength of stimulus, as the pressure fell after the second injection of ergotoxine, is shown in Fig. 2. An injection of 0T mgm. of adrenine is interposed, for comparison of the effect. It will be seen that each splanchnic stimu- lation causes a fall of blood-pressure, quite definite, but very small in com- parison with that produced by a moderate dose of adrenine. I have performed this experiment four times, and with uniform result. There can be no question of an effect on the contralateral supra-renal gland, as in two of the experiments both Avere extirpated. The effect can only be ascribed to a direct vasodilator effect of the