SKIN D.C POTENTIALS AND ENDOSOMATIC GALVANIC SKIN REACTION IN CAT

D.c. potential recordings have been made on different skin areas in cats. A negative d.c. potential exists on the volar, hairless skin areas of the paws. This "basal potential" persists even though the limb is denervated, decreases reversibily when the arterial blood circulation is arrested for a short time in the limb, but disappears when the animal is sacrificed. A d.c. potential change is also induced by intravenously administered succinylcholine. It is not limited to the skin but seems to arise in the striated muscles. The endosomatic galvanic skin reaction, GSR, induced after a period of rest by a single electrical shock to the distal stump of the dissected sciantic nerve, includes both a fast, negative and a slow, most often positive component. The amplitude of the negative component does not change during the above-mentioned d.c. changes. By repetitive stimuli the slow components fuse and cause a change in the basal potential. The amplitude of the fast component increases often simultaneously, but these two potential changes seem to be independent. The nature of the mechanisms maintaining and changing the basal potential and the relationships between the basal potential and the GSR are discussed.