Coagulation Not Hastened by Splanchnic Stimulation if the Adrenal Glands are Absent
The manner in which splanchnic stimulation produces its effects is indicated in the following experiments:
Nov. 28.—A cat was etherized, and through the orbit the central nervous system was destroyed to the midthorax. The blood vessels of the left adrenal gland were then quickly tied and the gland removed. The readings for a half hour before the left splanchnic nerve was stimulated averaged seven minutes, then—
| 4.38 to .40 | Stimulation of left splanchnic (glandless). | |
| .42 | 7 | minutes |
| .50 | 7 | “ |
| 5.02 to .04 | Stimulation of right splanchnic. | |
| .06 | 4 | minutes |
| .10 | 7 | “ |
| .18 | 7 | “ |
| .26 | 7 | “ |
Dec. 4.—A cat was etherized and pithed through the orbit to the neck region. The right and left splanchnic nerves were tied and cut in the thorax. The left adrenal gland was then carefully removed. These operations consumed about a half-hour. The following records show the effect of stimulating the left and right splanchnic nerves:
| 4.10 | 5 | minutes |
| .16 | 4.5 | “ |
| .25 to .28 | Stimulation of left splanchnic (glandless). | |
| .30 | 4.5 | minutes |
| .35 | 4.5 | “ |
| .40 | 7.5 | “ |
| .49 to .51 | Stimulation of right splanchnic. | |
| .55 | 4.5 | minutes |
| 5.00 | 2.5 | “ |
| .14 | 6 | “ |
| .23 to .25 | Stimulation of right splanchnic. | |
| .26 | 6 | minutes |
| .33 | 4.5 | “ |
| .38 | 3.5 | “ |
| .43 | 4.5 | “ |
| .49 | 5 | “ |
| .55 | 6 | “ |
The results in this experiment are represented graphically in [Fig. 31].
Figure 31.—Results of stimulating the left splanchnic nerves, 4:25-:28, after removal of the left adrenal gland; and of stimulating the right splanchnic nerves, 4:49-:51 and 5:23-:25, with right adrenal gland present.
Elliott’s evidence that in the cat the splanchnic innervation of the adrenals is not crossed has already been mentioned. If the gland is removed on one side, therefore, stimulation of the nerves on that side causes no discharge from the opposite gland. As the above experiments clearly show, splanchnic stimulation on the glandless side results in no shortening of the coagulation time; whereas, in the same animals, stimulation of the nerves on the other side (still connected with the adrenal gland) produces a sharp hastening of the clotting process.
The splanchnics innervate the intestines and liver even though the adrenal gland is removed. The foregoing experiments indicate that the nerve impulses delivered to these organs do not influence them in any direct manner to accelerate the speed of coagulation. Indeed, in one of the experiments (Dec. 4, see [Fig. 31]) a high reading about ten minutes after splanchnic stimulation on the glandless side suggests the possibility of an opposite effect. Direct stimulation of the hepatic nerves on one occasion was followed by a change of the clotting time from 4.5, 5, 4.5, 4.5 minutes during twenty-five minutes before stimulation to 4.5, 7, and 6 minutes during twenty minutes after stimulation.
Since with the adrenals present stimulation of hepatic nerves induces alteration of glycogen in the liver and quick increase of blood sugar,[2] just as splanchnic stimulation does, the failure of the blood to clot faster after stimulation of the hepatic nerves confirms the evidence already offered that faster clotting when adrenin is increased in the blood is not due to a larger amount of sugar present (see [p. 159]).
The liver and intestines cannot be made to shorten clotting time by stimulation of their nerves, but, as has already been shown (see [p. 157]), neither can adrenin act by itself to hasten the clotting process. Apparently the effect is produced by coöperation between the adrenals and the liver (and possibly also the intestines). Somewhat similar coöperation is noted in the organization of sugar metabolism; splanchnic stimulation in the absence of the adrenal glands does not increase blood sugar,[3] and in the absence of the liver adrenin is without influence.[4]
The variations of effect noted after splanchnic stimulation can be accounted for by variations in the adrenin content of the glands. Elliott[5] found, as previously stated, that animals newly brought into strange surroundings may have a considerably reduced amount of adrenin in their adrenals. The animals used in our experiments had been for varying lengths of time in an animal house in which barking dogs were also kept, and were therefore subject to influences which would be likely to discharge the glands.
The evidence that stimulation of splanchnic nerves, with accompanying increase of adrenal secretion, results in more rapid clotting of blood is especially interesting in relation to the experiments previously described, which showed that in pain and emotional excitement there is an increased secretion of adrenin into the blood. Does the adrenin thus liberated have any effect on the rate of coagulation? The observations here recorded were made in order to obtain an answer to that question.