犬

Although it is well known that eccrine sweat glands are found in the skin of foot pads of the dog, functional activity of the glands is still unknown. In this paper, by means of microspectrophotometry, the authors studied cytological changes of these glands induced by the pharmacological stimuli. The results obtained are as follows: 1) Eccrine sweating is responsible for the cholinergic agents as well as the adrenergic ones likely the results of the case in the apocrine glands previously reported. Of the two agents the former is especially sensitive. The minimum effective concentration of the cholinergic agents required to produce partial sweating is as low as 10^-12. 2) Sweating is easily observed by the naked eye when injected the agents intradermally in the skin of the foot pads. On the contrary of the fact that the orifices of human eccrine ducts open on the surface of the epidermal ridge, the ducts of the dog open through the epidermal furrows of the skin. 3) Marked cytological changes have been found in the eccrine sweat glands following the pharmacological stimuli such as systematic variation of mitochondria, secretion granules and PAS positive materials in dark and clear cells. Especially, many secretion vacuoles are appeared in the cytoplasm of clear cells after the intradermal injection of acetylcholine. 4) Cyclic changes of PAS positive materials contained in the gland cells have been observed microspectrophotometrically following the intradermal injection of sudorific agents. The amounts of mucopolysaccharides in dark cells increase temporarily just after the injection but 2 hours later they decrease to the minimum. On the other hand, the amounts of glycogen contained in clear cells decrease acutely soon after the injection and 2 hours later they seem to increase slightly. From morphological and physiological point of view, these phenomena suggest that two cell types are differentiated into quite different types respectively. 5) It has been supposed that physiological significance of the eccrine glands in the dog will be the mechanical defense from the circumstances by its secretory fluid including a large amounts of mucopolysaccharides.