The long-term objectives of this research program are to define the extent to which the dental pulp regulates the development, maintenance, and repair of its innervation and to elucidate the mechanisms for this regulation. The underlying hypothesis is that nerve growth factor (NGF) or other neuronotrophic factors act as mediators by which dental tissues influence the neurons which innervate them. In recent years, the dependence of peripheral sympathetic and sensory neurons on such factors from other target tissues has been demonstrated.
The specific aims of the proposed studies are (1) to determine whether those sympathetic and sensory neurons which innervate the dental pulp are dependent on NGF during the developmental period when the innervation to the pulp is established and (2) to determine whether reinnervation of the pulp following nerve injury is dependent on availability of NGF. The question of NGF dependence of neurons innervating the pulp will be addressed by assessing the consequences of NGF deprivation on the development and recovery from injury of intradental innervation of the rat molar. A condition of NGF deprivation will be accomplished using the well-established autoimmune model. Rats deprived of endogenous NGF in utero and neonatally will be anatomically evaluated for deficits in (1) neuron populations in the trigeminal and superior cervical ganglia and (2) in myelinated and unmyelinated nerve fiber numbers in the first mandibular molar, inferior alveolar nerve, and mental nerve. The proposed studies will further distinguish between immediate and permanent effects of NGF deprivation and effects of prenatal versus postnatal NGF deprivation. The possibility that NGF dependence is restricted to specific sub-populations of neurons innervating the pulp will also be explored. The possibility of an essential role of NGF in repair of dental nerve injury will be tested by evaluating recovery from inferior alveolar nerve section in mature animals deprived of endogenous NGF. These studies will advance understanding of the complex interactions between dental tissues and the neurons that innervate them.

Agency
National Institute of Health (NIH)
Institute
National Institute of Dental & Craniofacial Research (NIDCR)
Type
Research Project (R01)
Project #
5R01DE009137-02
Application #
3222963
Study Section
Neurology B Subcommittee 2 (NEUB)
Project Start
1991-02-01
Project End
1994-01-31
Budget Start
1992-02-01
Budget End
1993-01-31
Support Year
2
Fiscal Year
1992
Total Cost
Indirect Cost
Name
University of Mississippi Medical Center
Department
Type
Schools of Medicine
DUNS #
928824473
City
Jackson
State
MS
Country
United States
Zip Code
39216
Yang, Hong; Bernanke, Jayne M; Naftel, John P (2006) Immunocytochemical evidence that most sensory neurons of the rat molar pulp express receptors for both glial cell line-derived neurotrophic factor and nerve growth factor. Arch Oral Biol 51:69-78
Pan, Yan; Wheeler, Esther F; Bernanke, Jayne M et al. (2003) A model experimental system for monitoring changes in sensory neuron phenotype evoked by tooth injury. J Neurosci Methods 126:99-109
Pan, M; Naftel, J P; Wheeler, E F (2000) Effects of deprivation of neonatal nerve growth factor on the expression of neurotrophin receptors and brain-derived neurotrophic factor by dental pulp afferents of the adult rat. Arch Oral Biol 45:387-99
Naftel, J P; Richards, L P; Pan, M et al. (1999) Course and composition of the nerves that supply the mandibular teeth of the rat. Anat Rec 256:433-47
Wheeler, E F; Naftel, J P; Pan, M et al. (1998) Neurotrophin receptor expression is induced in a subpopulation of trigeminal neurons that label by retrograde transport of NGF or fluoro-gold following tooth injury. Brain Res Mol Brain Res 61:23-38
Qian, X B; Naftel, J P (1996) Effects of neonatal exposure to anti-nerve growth factor on the number and size distribution of trigeminal neurones projecting to the molar dental pulp in rats. Arch Oral Biol 41:359-67
Naftel, J P; Qian, X B; Bernanke, J M (1994) Effects of postnatal anti-nerve growth factor serum exposure on development of apical nerves of the rat molar. Brain Res Dev Brain Res 80:54-62
Naftel, J P; Bernanke, J M; Qian, X B (1994) Quantitative study of the apical nerve fibers of adult and juvenile rat molars. Anat Rec 238:507-16
Qian, X B; Naftel, J P (1994) The effects of anti-nerve growth factor on retrograde labelling of superior cervical ganglion neurones projecting to the molar pulp in the rat. Arch Oral Biol 39:1041-7