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