. The Journal of laboratory and clinical medicine . PHARMACOLOGICAL ACTION OF QUINIDINE 327 been supposed that qninidine paralyzes the inhibitory endings of the vagiin the heart. This action has been described as being similar to, but milderthan, that of atropine. In Fig. 16 the records of the auricular and ventricularcontractions are shown. The animal had previously been given 100 milli-grams of qninidine in small repeated doses. At the time when this tracingwas made the blood pressure had been reduced to a very low level by theqninidine and we feared to give another dose of the drug because
. The Journal of laboratory and clinical medicine . PHARMACOLOGICAL ACTION OF QUINIDINE 327 been supposed that qninidine paralyzes the inhibitory endings of the vagiin the heart. This action has been described as being similar to, but milderthan, that of atropine. In Fig. 16 the records of the auricular and ventricularcontractions are shown. The animal had previously been given 100 milli-grams of qninidine in small repeated doses. At the time when this tracingwas made the blood pressure had been reduced to a very low level by theqninidine and we feared to give another dose of the drug because it wouldprobably stop the heart (the animal was getting artificial respiration). Ourobject was to give the qninidine all possil)le opportunity to act on the vagi. l<ig. 16. endings and then to determine by electrical stimulation of the nerve in thecervical region whether inhibition of the heart could still be produced. Atthe point indicated in the left of the tracing the right vagus nerve was stimu-lated and a prompt complete inhibition of the heart was produced. Thislasted longer in the auricle than in the ventricle, which presently brokethrough the inhibition, but still showed its effects while the stimulation wascontinued. Following this, and while the inhibitory effect was still wellmarked in the auricle, an injection of 1 milligram of atropine was given byway of the femoral vein and this promptly stopped the lingering inhibitoryeffects in the auricle which responded by a marked increase in both rate andamplitude of its beat. Following this the right vagus nerve was again stim- 328 THE JOURNAL OF LABORATORY AXD CLINICAL MEDICINE iilated, but no inhibitory effects were produced on the heart. We concludefrom this (and other similar experim
Size: 1466px × 1705px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubject, booksubjectmedicine
