To visualize adrenergic and cholinergic nerve endings under electron microscope.
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.
- 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.
Autonomic nerves are present in the odontoblast/predentin border and in the predentin.