To visualize adrenergic and cholinergic nerve endings under electron microscope

By Inoue H, Kurosaka Y, Abe K

Date: 01/1992
Journal: JOE

Purpose:

To visualize adrenergic and cholinergic nerve endings under electron microscope.

Materials/Methods:

N = 20 canines from 10 dogs.

Canines extracted. Apical ¼ horizontally sectioned. Both apical half & coronal half of roots were sectioned longitudinally. One half was observed under electron microscope & the other decalcified.

  • Adrenergic nerves: sympathetic nervous system; neurotransmitters are epi, noradrenaline, dopamine.
  • Histo = uniform, electron dense granular vesicles.
  • Cholinergic nerves: parasympathetic nervous system; neurotransmitter is acetylcholine.
  • Histo = not electron dense agranular vesicles that are scarcely denser than cytoplasm.

Results:

  • Autonomic nerves rarely present in odontoblast layer, predentin, and dentin. More often found in close proximity.
  • Adrenergic nerve endings present close to odontoblast/predentin border, in dentinal tubules, & predentin.
  • Cholinergic nerve endings rarely present in the odontoblast layer or predentin.
  • Prominent degranulation associated with collagen formation.

Clinical Significance:

Autonomic nerves are present in the odontoblast/predentin border and in the predentin.