A reversed action of the vagus on the mammalian heart / by H.H. Dale, P.P. Laidlaw, and C.T. Symons.

  • Henry Hallett Dale
Date:
[1910?]
Catalogue details

Licence: Public Domain Mark

Credit: A reversed action of the vagus on the mammalian heart / by H.H. Dale, P.P. Laidlaw, and C.T. Symons. Source: Wellcome Collection.

    5/24 (page 1)
    [Reprinted from the Journal of Physiology, Vol. XLI. No. 1, 1910.] A REVERSED ACTION OF THE VAGUS ON THE MAMMALIAN HEART. By H. H. DALE, P. P. L AIDE AW and C. T. SYMONS1. {From the Wellcome Physiological Research Laboratories.) Introductory. A cardio-accelerator action of the mammalian vagus has frequently been described, and in several instances has been regarded as indicating the presence in the vagus itself of true accelerator fibres. The earlier observations, such as those of Rutherford(1) (who, indeed, explained the phenomenon otherwise), of Boehm(2), or of Schiff(3), and the later experiments of Arloing(4), whether the accelerator action was revealed by the aid of drugs such as atropine or curare, or by degenerative section of the nerve, are alike open to explanation by the existence in the vagus of recurrent sympathetic fibres, arising from the stellate or the inferior cervical ganglion, joining the vagus by one of the communicating branches which unite it with the anterior limbs of the annulus, and looping back to their distribution in the cardiac branches. We have ourselves in one case, which will be mentioned later in more detail, obtained a result by means of degenerative section similar to those of Arloing, and susceptible of the same explanation. The phenomenon which is our main concern in this paper is of a different kind. It can be reproduced with regularity under given conditions, and we shall give evidence that it has no connexion with the true sympathetic system. Whether it is due to the presence in the vagus of fibres which are normally accelerator in function is still open to question. 1 The phenomenon with which this paper deals was first observed accidentally by Dale and Symons in 1907 and partly investigated: alter an interval the investigation was resumed and brought to its present stage by Dale and Laidlaw, For preliminary note see This Journal, xxxix. Froc. Fhys. Sac. p. xiii. 1909,