[Mast cells of the outer coat of the arteries of the basis cerebri].

Labrocytes situated in the external tunica of the cat basis cerebri arteries have been studied by means of Falck's method and electron microscopically. It has been stated that dilated areas in islets of the mast cells, having ultrastructure peculiar for actively secreting formations, are situated at the distance of 80-100 nm from the smooth muscle cells of the middle tunica. Close structural and functional relations have been found to exist between the adventitial labrocytes and neural conductors of the arteries. Participation of the arterial mast cells in mechanisms of local selfregulation is supposed.