抄録
Histochemical localization of cholinesterase (ChE) activity in the baroreceptors of the carotid sinuses of the mouse, rat and cat was studied by light and electron microscopy. ChE-positive sites were identified by light microscopy as brownly-stained small plaques both in the mouse and in the rat, or as intensely-stained large plaques or bands in the cat, extending from the transitional zones between the adventitia and media as far as the outer half of the media. By electron microscopy it was evident that the reaction products were deposited in spaces between the axon terminals and the surrounding Schwann cells as well as on the acellular materials around the Schwann cells, including the Schwann cell basement membrane. Enzyme activity was also noted in the cisternae of the rough endoplasmic reticulum as well as in the nuclear envelope of some Schwann cells associated with the axon terminals. It is thought that ChE is synthesized and released by Schwann cells that are associated with the axon terminal. Inhibitor experiments showed that the enzyme noted in the baroreceptors was non-specific ChE as in the case of other mechanoreceptors such as Meissner and Pacinian corpuscles. The fact that the baroreceptor of the carotid sinus has such an intense ChE activity indicates that this enzyme has some important and specific roles in the functions and the maintenance of the receptor.
