BLOOD-VESSELS AND NERVE-FIBERS IN RAT INCISOR PULP - IMMUNOELECTRON MICROSCOPIC OBSERVATION WITH ANTI-SUBSTANCE-P ANTIBODY

The distribution of nerve fibers with special reference to their posit ional relationship with blood vessels in the pulp of the rat mandibula r incisor was investigated by light and electron microscopic immunohis tochemistry using polyclonal anti-substance P antibody. In the center of the pulp, numerous immunoreactive nerve fibers with varicosites wer e found along larger blood vessels. In the periphery of the pulp, ther e were two layers of capillary plexus; an odontoblastic and a subodont oblastic. Many nerve fibers, showing varicosities, were located in the subodontoblastic region, and some revealed a close association with p ericytes of capillaries of the subodontoblastic plexus. A few nerve fi bers entered the odontoblast layer, but no nerve fibers were seen to b e associated with the odontoblastic capillary plexus. The results sugg est that the local regulation of blood flow takes place not only in la rger blood vessels but also in the capillaries of the rat incisor pulp .