Responses of isolated bronchial muscle to ganglionically active drugs / by D.F. Hawkins and W.D.M. Paton.

  • Hawkins, D. F. (Denis Frank)
Date:
[1958?]
Catalogue details

Licence: In copyright

Credit: Responses of isolated bronchial muscle to ganglionically active drugs / by D.F. Hawkins and W.D.M. Paton. Source: Wellcome Collection.

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    [Reprinted from the Journal of Physiology, 1958, Yol. 144, No. 2, p. 193.] PRINTED IN GREAT BRITAIN J. Physiol. (1958) 144, 193-219 RESPONSES OF ISOLATED BRONCHIAL MUSCLE TO GANGLIONICALLY ACTIVE DRUGS By D. F. HAWKINS* and W. D. M. PATONt From the Department of Pharmacology, University College London, and University College Hospital Medical School, London, W.C. 1 (Received 9 December 1957) It is generally accepted that the efferent innervation of the bronchial mus¬ culature is by branches from the vagus nerve and from the thoracic sympathetic trunk, entering the lung at its hilum (Macklin, 1929). The trachea is thought to have a similar supply. The existence of ganglion cells in the lung, distributed along the branches of the bronchial tree, has been known since the time of Remak (1844). The autonomic innervation appears to follow the usual pattern, in that the vagus fibres entering the lung are preganglionic and form synapses with Remak’s ganglia within the lung; processes from these cells end on the smooth muscle cells in the walls of the bronchi. The sympathetic supply consists of post-ganglionic fibres which end directly on the smooth muscle of the bronchi. Although it is usually held that the vagus nerve mediates bronchoconstric- tion and the sympathetic supply bronchodilatation, there is evidence that this simple picture is not completely correct. For instance, some workers have observed that under certain conditions excitation of the vagus, instead of producing the usual bronchoconstriction, may elicit bronchodilatation. There is little doubt that some of the earlier workers in fact stimulated not the vagus alone, but the vagosympathetic trunk. Further differences of opinion may have arisen from failure to realize the difficulty of demonstrating broncho¬ dilatation in a preparation which has little tone under the experimental conditions. Dixon & Brodie (1903), who were aware of both these difficulties, concluded that the vagus nerve itself contained both bronchodilator and bronchoconstrictor fibres. This conclusion has subsequently been confirmed in guinea-pigs, cats, dogs and rabbits, the bronchodilator action of the vagus being more readily demonstrable after a dose of some bronchoconstrictor drug. Since the vagal bronchomotor fibres have been shown to end on the * Present address: Department of Pharmacology, Harvard Medical School, Boston, U.S.A. ■j* Present address: Department of Pharmacology, Royal College of Surgeons, London, W.C. 2. 13 PHYSIO. CXLIV