Innervation of blood vessels in the rat incisor pulp: A scanning electron microscopic and immunoelectron microscopic study

Abstract

Although two types of nerve endings have been proposed to innervate blood vessels in the dental pulp, the precise innervation pattern is not well understood. This is mainly due to the lack of information regarding the positional relationships of nerve fibers with blood vessels at the electron microscopic level.The rat incisor pulp was investigated by scanning electron microscopy (SEM) after connective tissue digestion and by transmission electron microscopy after immunohistochemical localization with polyclonal anti-PGP 9.5 antibody.SEM specimens revealed that unmyelinated nerve fibers passed through the tunica adventitia of the blood vessel in the center of the pulp and that these fibers then entered the tunica media of the smaller arterioles. The nerve fibers divided into many collaterals, and these terminated on the surface of smooth muscle cells and endothelial cells. The fibers extended toward smaller vessels. The terminal fibers then reached the subodontoblastic capillary plexus and terminated on pericytes, while the odontoblastic capillary plexus had no direct innervation. In the pulpal venules, nerve fibers were located adjacent to the pericytes and endothelial cells, and they extended toward postcapillary venules. The same results were confirmed by immunoelectron microscopy.The present study demonstrated that in the rat incisor pulp the microvasculature as well as larger vessels were directly innervated by free nerve endings, suggesting that the local regulation of blood flow could take place not only at larger vessels but also at the level of the microvasculature in this tissue. Anat.

Secretion of Shh by a Neurovascular Bundle Niche Supports Mesenchymal Stem Cell Homeostasis in the Adult Mouse Incisor

“…The mouse incisor is innervated by sensory and sympathetic nerves (Ishizuka and Hiura, 1992; Johansson et al, 1992; Tabata et al, 1998; Zhang et al, 1998) but is devoid of parasympathetic nerves (Olgart, 1996; Sasano et al, 1995). Nerve fibers accompanying the arteries are located within the periarterial region, which is similar to the tunica adventitia of free arteries.…”

Bovine circumvallate taste buds: Taste cell structure and immunoreactivity to α‐gustducin

“…The avidin‐biotin complex (ABC) visualization method was reported in our previous study (Tabata et al, 1998). Briefly, the circumvallate papillae were put into a solution containing 0.1% glutaraldehyde and 4% paraformaldehyde in a phosphate buffer for 4 h on ice.…”

A photochemical method for in vitro evaluation of fluid flow in human dentine

“…Bacteria can invade dentinal tubules, but do not invade dentine because of the outward movement of dentinal fluid that contains immunoglobulins. 21 Thus, coronal dentine may have weak defences against bacteria and noxious agents penetrating into dentinal tubules. Previous studies reported that a higher rate of dentinal fluid flow may induce a larger stress on mechanoreceptors, resulting in an elevated intradental nerve firing rate.…”