Abstract
The experiments here reported deal with a series of studies on the analysis of the vasomotor response in asphyxia. The first of this series had particular reference to the part played by the splanchnic constrictor fibers in the response. The second series was concerned with the relation of the activity of these fibers to the secretion of adrenalin. The procedure throughout was the infliction of a complete but temporary anemia on the entire brain, according to the technique of Stewart et al., 1 by clamping off the arterial circulation of the head. Occlusion in these experiments was used essentially as a constant and powerful stimulus for setting off a vasomotor response which was known to be aroused by the medullary centers. The experiments were all done on cats. Certain additional controls had to be obtained for the work on the adrenals which will be described below. These experiments were undertaken in connection with the studies on the functional organization of the nervous system carried on by Professor F. H. Pike and his collaborators.
THE SPLANCHNIC EFFECT
The evidence on the particular nervous channels involved in the vasomotor response to asphyxia was obtained by testing the response after the infliction of given nervous lesions. The response was found to depend almost entirely on the constrictor fibers of the splanchnic nerves. No lesion of the extrinsic cardiac nerves significantly altered the response to occlusion. Injection of curare, with the elimination of the pressor effect produced indirectly by the skeletal innervation also did not modify the response appreciably. However, section of the splanchnic nerves immediately below the diaphragm abolished all vasomotor response to asphyxia.
It was possible to work out the pathway of the splanchnic fibers with more precision.
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