Abstract
The stromuhr referred to in the preceding abstract was used in obtaining quantitative data regarding the portal circulation. The experiments so far performed have given an average flow of 1.56 c.c. per second in the splenic vein (weight of spleen 78 grams) and a flow of 1.05 c.c. per second in the mesenteric.
In the case of the spleen, the veins draining the pyloric end of the stomach and fatty tissue of this region were ligated. The stromuhr was then inserted centrally to the last branch draining this organ. The venous pressure was recorded centrally to the instrument. In the case of the mesenteric the stromuhr was inserted distally to the point of entrance of the vena gastrolienalis.
The nerves innervating the spleen and intestines were stimulated electrically while the blood flow in the veins was being measured. For the stimulation were selected first of all the entire bulk of the præ or post ganglionic fibers, and later on the most prominent fibers of the post-ganglionic paths.
On stimulation of the post-ganglionic fibers innervating the spleen (splenic plexus) vaso-constrictory effects of a very pronounced character were obtained. Immediately on stimulation the flow in the splenic vein showed an extraordinary increase which soon gave way to an equally pronounced decrease. The flow regained its normal value sometime after the cessation of the stimulation.
The primary increase in the flow is not due to a vaso-dilation of the splenic blood vessels, but to a squeezing out of the blood “resident” in the spleen. Not until this amount of blood has been expelled by the constricting blood-vessels, can the decrease become evident. Thus, it appears that constrictory effects are obtained from the first when the nerves aforesaid are stimulated.
Although I have tested the vaso-motor power of several of the fibers composing the plexus, I have succeeded in obtaining only vaso-constrictory results.
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