During development mammals demonstrate a transition from suckling to chewing behavior for the ingestion of nutrients. These behaviors and the transition between them are essential for normal development and survival. Two critical components comprising the neural circuitry responsible for oral-motor behaviors are trigeminal motoneurons and mesencephalic trigeminal neurons. Insight regarding oral-motor development will be gained by correlating the development of terminals innervating trigeminal motoneurons and mesencephalic trigeminal neurons with the development of neurotransmitter receptor complexes utilized to modulate the activity of these neurons. This study will be the first to characterize oral-motor development using chemical neuroanatomical techniques. This will be accomplished by correlating changes in the glutamatergic and GABAergic innervation of trigeminal motoneurons and mesencephalic trigeminal neurons with the ontogeny of NMDA, AMPA, and GABAa receptors in these neurons during early postnatal development. Three different experimental protocols will be performed on rats at postnatal day 1, 5, 15, and 25 as these ages represent critical periods in oral-motor development. In the first set of experiments, a polyclonal antibody against glutamate and a polyclonal antibody against glutamate decarboxylase (GAD) will be used to label glutamatergic and GABAergic terminals throughout the trigeminal motor nucleus and mesencephalic trigeminal nucleus. In the second set of experiments, receptor immunohistochemistry using antibodies against NMDA, AMPA, and GABAa subunits will be used to describe the temporal and spatial expression of NMDA, AMPA, and GABAa receptors in trigeminal motoneurons and mesencephalic trigeminal neurons. Finally, quantitative receptor autoradiography using [3H]MK-801, [3H]AMPA, and [3H]muscimol will be used to determine density changes of NMDA, AMPA and GABAa receptors respectively. The results from these studies will provide insight into the role of glutamate and GABA in controlling neonatal trigeminal motoneuron and mesencephalic trigeminal neuron activity in order to further understand the development and function of early oral-motor circuits.

Agency
National Institute of Health (NIH)
Institute
National Institute of Dental & Craniofacial Research (NIDCR)
Type
Small Research Grants (R03)
Project #
5R03DE012029-02
Application #
2882725
Study Section
NIDCR Special Grants Review Committee (DSR)
Project Start
1998-02-15
Project End
2001-02-14
Budget Start
1999-02-15
Budget End
2001-02-14
Support Year
2
Fiscal Year
1999
Total Cost
Indirect Cost
Name
University of Southern California
Department
Miscellaneous
Type
Schools of Medicine
DUNS #
041544081
City
Los Angeles
State
CA
Country
United States
Zip Code
90089
Turman Jr, J E; Rich, R A; Chandler, S H (2001) GABA(A) receptor beta2/beta3 subunit and GAD67 immunoreactivity in the trigeminal motor nucleus during early postnatal development. Brain Res Dev Brain Res 130:155-8
Turman Jr, J E; Hiyama, L; Castillo, M et al. (2001) Expression of group I and II metabotropic glutamate receptors in trigeminal neurons during postnatal development. Dev Neurosci 23:41-54
Turman Jr, J E; MacDonald, A S; Pawl, K E et al. (2000) AMPA receptor subunit expression in trigeminal neurons during postnatal development. J Comp Neurol 427:109-23
Turman Jr, J E; Ajdari, J; Chandler, S H (1999) NMDA receptor NR1 and NR2A/B subunit expression in trigeminal neurons during early postnatal development. J Comp Neurol 409:237-49