Reflex changes in sympatho-adrenal medullary functions in response to various thermal cutaneous stimulations in anesthetized rats.

The effects of various thermal stimulations of restricted skin areas with a thermal probe on the adrenal sympathetic efferent nerve activity and catecholamine (CA) secretion rates from the adrenal medulla were studied in alpha-chloralose-urethane anesthetized rats. Both cold and warm stimulations of abdominal skin either below 10 degrees C or above 43 degrees C produced reflex increases in nerve activity as well as CA secretion rates, whereas stimulations between 13 degrees C and 40 degrees C were ineffective in producing significant changes in these variables. The stimulation of chest and abdominal skin areas was more effective in producing adrenal sympathetic nerve responses than that of the shoulder, thigh or scrotum skin.