Development of the pioneer sympathetic innervation into the dental pulp of the mouse mandibular first molar.
OBJECTIVE
Our goal was to study the development of pioneer sympathetic innervation of dental pulp of mouse mandibular first molar.


METHODS
We used double fluorescent immunohistochemistry with tyrosine hydroxylase (TH) and anti-medium-chain neurofilament (2H3) antibodies to detect sympathetic and sensory nerve fibres. Serial sections of whole teeth from postnatal days (PN) 0-14, trigeminal and sympathetic superior cervical ganglia of PN 15 mice were examined with confocal microscope.


RESULTS
There were two main findings. The unexpected finding was that 2H3 antibody was specific only for sensory nerve fibres and neurons and failed to stain either sympathetic nerve fibres or neurons. The main finding was that although both sympathetic and sensory nerve fibres were already seen near the tooth germ at the newborn stage, the pioneer sympathetic nerve fibres were first observed in the dental pulp only after the onset of root formation on day 9, in contrast to sensory nerve fibres which entered the tooth already on day 4.


CONCLUSIONS
Pioneer sympathetic innervation of dental pulp starts on postnatal day 9 and follows sensory innervation. This indicates differential developmental regulation of the initial sensory and sympathetic innervation of teeth and provides essential background data for further studies on the molecular regulation of pulp innervation.
Moe
Kyaw
K
Department of Biomedicine, Faculty of Medicine and Dentistry, University of Bergen, Jonas Lies vei 91, N-5009 Bergen, Norway.
Kettunen
Päivi
P
Kvinnsland
Inger Hals
IH
Luukko
Keijo
K
D000818:Animals; D000831:Animals, Newborn; D003782:Dental Pulp / Q000294:innervation*; D007150:Immunohistochemistry; D008334:Mandible / Q000294:innervation*; D051379:Mice; D008963:Molar / Q000294:innervation*; D009412:Nerve Fibers / Q000502:physiology*; D009414:Nerve Growth Factors / Q000502:physiology; D014083:Tooth Germ / Q000294:innervation*; D012668:Trigeminal Ganglion / Q000502:physiology*
D009414:Nerve Growth Factors