Experimental Studies of the Effect of the Electrical Stimulation of the Spinal Cord on the Electrocardiograms

Abstract

The causal relations between various neuroses and the distribution of subclinical adhesive arachnoiditis cerebrospinalis have been extensively studied by Maekawa and his students. The neurocirculatory asthenia (N.C.A.), a type of neurosis, is frequently associated with abnormal electrocardiograms. It is also known that the stimulation of the peripheral sympathetic nerve produces electrocardiograms of insufficiency pattern. In this paper the author tried to elucidate the possible role of the spinal sympathetic nervous system supplying the heart in the pathogenesis of N.C.A. by studying the effect of the electrical stimulation of the spinal cord in dogs on the electrocardiograms. Methods After adult dogs were laminectomized under anesthesia, a pair of concentric electrodes was inserted into the spinal cord, and the electrical stimulation was applied at 4 to 15 volts for about 5 to 15 seconds. Electrocardiograms were recorded before, during and after the electrical stimulation. Results and Discussion In 30 of 36 tested animals the electrical stimulation of the spinal cord produced electrocardiographic changes in ST and T waves. Although changes could be produced either with the upper thoracic cord or lower thoracic cord stimulation, electrocardiographic changes were more frequent in incidence and severe in degree with the former mode of the stimulation than with the latter. A still stronger effect could be produced when the two areas were stimulated simultaneously. The maximum effect was obtained at 2.5 mm depth of the insertion of the stimulating electrode; in this case the tip of the electrode was located near the lateral horn of the spinal cord. Although the electrical stimulation of the spinal cord produced an elevation of the blood pressure concomitantly with the electrocardiographic changes, the observed electrocardiographic changes were not possibly reactions secondary to the elevation of the blood pressure. Altered electrocardiograms and elevated blood pressure are probably two distinct manifestations of a single reaction process of the organism to the stimulation, i.e., the coronary vasoconstriction on the one hand, and generallized peripheral vasoconstriction on the other.