The somato-adrenal medullary reflexes in rats

In chloralose-urethane-anesthetized rats, the effects of somatic stimulation on the adrenal sympathetic efferent nerve activity as well as the adrenal catecholamine secretion were examined. Single shock of the thoracic thirteenth spinal afferent nerve evoked reflex discharges in the adrenal sympathetic efferent nerve. The spinal and supraspinal reflex components evoked by the myelinated and unmyelinated afferent stimulation were identified. The adrenal nerve activity was usually increased reflexly by pinching of the lower chest or upper abdominal skin area in the central nervous system (CNS)-intact animals. Secretion of adrenal epinephrine was noted to be increased reflexly by pinching the lower chest or upper abdominal skin in the central nervous system intact animals.