Functional Activity of the Eccrine Sweat Glands in the Toe-pads of the Dog.

The functional activity of the eccrine sweat glands in the toe-pads of non anesthetized dogs was investigated. Spontaneous sweating of central origin was found to be considerable in dogs in early months (within 1-3 months) of birth. This sweating was easily blocked by local administration of atropine, but not by dihydroergotamine, indicating a cholinergic nerve supply to the sweat glands. The responsiveness of the glands to local injections of adrenaline, nor -adrenaline, isopropylnoradrenaline, carbaminoylcholine, acetylcholine, mecholyl and pilocarpine was determined with the toe-pads in which the spontaneous sweating had been eliminated by blocking the peripheral nerves with procaine, using the band method. The axon reflex sweating was found to be elicited by local application of nicotine. The occurrence of this response was limited to the toe-pads which had been maintaining the ability to produce a considerable spontaneous sweating. The ability of producing spontaneous sweating and the responsinveness to the sudorific agents of the glands were reduced with advancing age. Further more, the responsiveness to the sudorific agents was found to decrease progres -sively following the denervation of the glands.