Uniformed Services University of the Health Sciences
4301 Jones Bridge Road
Bethesda, Maryland 20814
The research program in this laboratory is focused on plastic responses of motoneurons during development and regeneration. The major interest is to gain an understanding of developmentally-regulated substances that are re-expressed after nerve injury to adult motoneurons. Studies center on two different types of substances: those that are produced at high levels during ontogeny and either progressively decline to low levels or are not detectable in intact adult motoneurons. Developmental plasticity studies involve 1) defining profiles of gene expression and 2) determining the types of signal transfer mechanisms that regulate changes in the levels of expression of these substances during ontogeny. Experiments involve surgical and chemical manipulation of central (local neuropil environment around the motoneuron) and peripheral (injured nerve and its innervation target) developmental events to examine whether the down-regulation in intact motoneurons is coincident with a defined phase of glial/Schwann cell development and if it is controlled by events at the growing tip of the axon, the postsynaptic neuromuscular junction or presynaptic input to the motoneuron. The other phase of research is to investigate the role of these substances to changes in and around axotomized adult motoneurons that are considered germane to regeneration: whether the up-regulation of these substances influences anterograde (growing axonal tip at the injury site and reinnervation of the target site) and retrograde (glial reaction and afferent synaptic displacement) regenerative processes. Techniques utilized in carrying out this research program include general and stereotaxic surgery, neurotrophic factor or implants, immunocytochemistry, image analysis, the polymerase chain reaction, as well as horseradish peroxidase labeling and nerve stimulation to assay anatomic and functional reinnervation.
Walsh, D. W., Ho, V. B., Borke, R. C. And Rovira, M., Anomalous Course of the Common Carotid Arteries: CT and MR( A) Illustration, Angiology 49: 235-238, 1998.
Nash, H. H., Borke, R. C. and Anders, J. J. A New Method of Purification for Establishing Primary Cultures of Ensheathing Cells from the Adult Olfactory Bulb. Glia 34, 81-87, 2001.
Nash, H. H., Borke, R. C. and Anders, J. J. Ensheathing Cells and Methylprednisolone Promote Axonal Regeneration and Functional Recovery in the Lesioned Adult Rat Spinal Cord, In Press J. of Neuroscience, 2002.
Snyder, S.K., Byrnes, K.R., Borke, R.C., Sanchez, A. and Anders, J.J. Quantitation of Calcitonin Gene-Related Peptide mRNA and Neuronal Cell Death in Facial Motor Nuclei Following Axotomy and Low Power Laser Treatment, In Press, Lasers in Surgery and Medicine, 2002.