Response of adrenal efferent nerve activity to noxious stimulation of the skin.

The effect of pinching the various segmental skin areas (neck, forepaw, lower chest, abdomen, thigh, hindpaw) on adrenal sympathetic efferent nerve activity which contributes to secretion of adrenal medullary hormones was examined in anesthetized rats. In the spinal cord-intact animal, pinching the lower chest, abdomen, forepaw or hindpaw produced a large reflex increase in efferent nerve activity. The response to pinching neck or thigh was small. In the spinalized animal, pinching the lower chest or abdomen produced a great response, but pinching the other skin areas including forepaw, hindpaw, neck, thigh produced little response. It is suggested that the potent segmental organization of the cutaneo-adrenal nerve reflex within the spinal cord is modified into a generalized pattern by the supraspinal structure.