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Discussion Of Stimulation George C. Taplin, M. D., D. O.
Dr. Cherry makes the point that functional activity can be increased by mechanical stimulation and decreased by mechanical inhibition without correcting the causative lesions back of the functional error. I wish to emphasize this statement because I have found it to be true in many clinical experiences. About three years ago I was called to an adjoining state to my own to see an aged woman who was dying of chronic nephritis complicated with aortic incompetence and mitral regurgitation. She was under the constant care of her family physician and two eminent specialists, one from New York City, and one from Boston. When I was called, her physicians had summoned the family to her side. She had been unconscious for several days, and for twenty-four hours previous to my arrival no urine had been secreted. Occasional attacks of heart failure had been overcome by the powerful heart stimulant, nitro-glycerine, and the administration of oxygen gas. I do not think there was the least possibility of saving or of rallying her for any great length of time. The case was too far advanced. However stimulation frequently applied to the renal center revived the action of the kidneys, and in the subsequent attacks of heart failure, when the fingers would become livid and the pulse imperceptible, stimulation of the cardiac center would bring back the heart action quicker than nitro-glycerine had previously done. The pulse would again be felt and the extremities regain normal color. I did all that I could for her and watched her practically without intermission for nearly four days, during which time I stimulated the cardiac center through a dozen or more such crises. I told the relatives frankly that the ultimate result could be but one thing; that I was powerless to do more than I was doing. The family physician was a long-standing friend of the patient, and some of her relatives felt that she would prefer him at her bedside at the last. This proposal I willingly agreed to. I think this process could have been continued for some time longer before all power of reaction to stimuli would have been gone. I think if the patient had been seen a few months earlier the prognosis would have been vastly better even though she was past 70 years of age. A few hours after my departure she passed away in one of these attacks. I mention this case rather than some of more favorable termination, on account of the immediately visible evidence of the effects of stimulation upon the heart and kidneys. Dr. Cherry has cited an example of restoring equilibrium by stimulation and inhibition, thus curing a case in which no lesion existed other than misplacement of fluid tissues. This is just as truly the correction of a lesion, therefore osteopathic, as the setting of a bone, or the adjustment of a ligament. Other cases may be cited where stimulation and inhibition may produce correction; for example, the removal of intestinal obstruction by stimulation, or the checking of diarrhea by inhibition. There is one statement in Dr. Cherry's paper with which I, at the present time, do not agree. That is in reference to vaso-dilators. I do not believe that they exist as such. I see no need of them, and no adequate mechanical principle by which they might work. In general the automatic functions are stimulated in proportion to the activity of their cerebro-spinal connection. The vasomotor centers are sympathetic nerve centers controlling the muscles in the blood vessel walls. When a vaso-motor center is stimulated these muscles in the area controlled by the center contract, with consequent constriction of the blood vessels. When the center is less active these muscles relax and dilation occurs in response to blood pressure. We do not need a special mechanism to relax our voluntary muscles. When the motor nerve diminishes its stimulus, the muscle relaxes by such combined forces as gravity, its own elasticity and the elasticity of surrounding structures. So in the vascular system, the muscles in the vessel walls contract or relax in proportion to the vaso-motor stimulus. The blood pressure and elasticity is ample to produce proportionate dilation immediately, when the vaso-motor center allows the slightest relaxation of the vascular muscles. When we reduce cerebral congestion by inhibitory treatment in the suboccipital region it is not by inhibition of the vasodilators, but by inhibition of the cerebro-spinal connections to the superior cervical sympathetic, which has the vaso-motor mechanism for the head, having ascended from the vasomotor centers in the dorsal cord. The inhibition of the cerebro-spinal activity allows a proportionate increase in the sympathetic action consequently vasoconstriction results in the vessels of the head. The physiological congestion of the digestive tract during active digestion is not due to stimulation of the vasodilators, but to stimulation of pneumogastric, thereby decreasing vasoconstriction. The synchronous increase in the sympathetic activity of the gastrointestinal muscular and secretive functions is brought about by the vaso-dilation above referred to. This vaso-dilation increases the local venosity of the blood which chemically stimulates Auerbach's and Meissner's plexi in the intestinal walls. Uterine congestion from exposure of the feet to cold and dampness is not due to stimulation of vasodilators but to stimulation of cerebro-spinal nerves which centers in the lumbar enlargement of the cord associated with the motors to the uterus. This cerebro-spinal stimulation as previously stated and illustrated causes inhibition of the vaso-motor center, thus allowing dilation to the part controlled. Now to return to the general subject. Machines have what
are called dead centers, that is, positions of the machinery from
which it is impossible to start motion. There are doubtless
dead centers in the human machinery. I think it is theoretically
possible to adjust the mechanism of the body and at the same time
not start the machinery. It would be like winding a clock
and not giving the pendulum motion. I do not expect to illustrate
this clinically. However, since the subject is given me to
champion, I wish to present its widest possibilities. If any
here wish to illustrate to themselves, by a simple way the efficacy
of stimulation let them irritate the mucous membrane of the nose
with a feather. They will be rewarded by an emphatic demonstration
of stimulation - a sneeze. This is a very ordinary but nevertheless
effective proof because so slight a stimulation is necessary and
so, violent a physiological response is obtained. |