Nervous control of the lungs: broncho- and vaso motor responses of guinea-pig lungs, produced by drug injections and nerve stimulations

In isolated pertused lungs of the guinea-pig (1) Acetyl Choline raises the respiratory pressure and diminishes the venous oùtflow; both effects are abolished by Atropine. (2) In general stimulation of the peripheral and of the cervical vago- sympathetic nerves causes a similar rise of intrapulmonary pressure and a diminution in outflow. In exceptional cases the I.P.P. falls, an effect which may be due to concomitant stimulation of the cervical sympathetic nerves. (3) Adrenaline leads to a variety of responses: a rise of I.P.P. accompanied by a fall in V.A. being the most frequently found. Five out of the total of 14 responses were in favour of the independence of the vaso- and bronchomotor mechanisms. In one instance an I.Y.P. rise occurred together with an V.O. increase . (4) Stimulation of the peripheral end of the cut C .V. usually causes a rise in I .P. associated with a diminution in outflow. (5) Only 3 responses were obtained with stimulations of the peripheral ends of cut cervical sympatheti In one a rise in I.P.P. was obtained; the flow wa not recorded. In other two responses occurred after an administration of Ergotoxine - a fall in I.P.P. with no change or a questionable diminution of outflow are recorded. (6) Ergotoxine reverses the effects of stimulation of the cervical vagus converting an I.P.P. + V.O. to an I..P. - R.P.sl. +; as also the respiratory pressure rise to an I.P.P. fall when the entire G.V.S. is stimulated. (7) Examination of spontaneous variations shows that V.O. and I.P.P. changes may occur in an unassociated manner; and from this and all data from above observations it is concluded that the vasomotor and respiratory pressure mechanisms are often mechanically affecting each other, and are in fact entirely independent