The long term objectives of this research are to understand the bases of recovery of function in the spinal cord following partial devervation. The relationship of latent synapses to recovery of function will be studied by comparing response to cutaneous and nerve stimulation in normal and deafferented animals. The role of collateral sprouting in mediating increased responses to high threshold stimuli following lesions will be assessed by HRP labelling of individual high-threshold afferents in normal and partially deafferented animals. The hypothesis that some loss and recovery of function following lesions can be accounted for by a transient failure of synaptic transmission will be tested by recording electrical properties of dorsal horn neurons related to excitability. Analysis will be carried out using populations of nerve cells whose properties have been well characterized in normal animals, namely, the cells of origin of the spinocervical tract, and high-threshold A-delta mechanoreceptive afferent fibers. The methods to be used include intra- and extracellular electrophysiological recording from spinocervical tract neurons following acute and chronic dorsal root and peripheral nerve lesions in cats. Responses to both mechanical stimulation of the skin and electrical stimulation of nerves will be evaluated. The effects of acute injury will be compared with those of reversible conduction block of nerves and dorsal roots. These studies are related to the health goals of preventing disability following peripheral nerve or spinal injury, and rehabilitating individuals with chronic spinal cord or peripheral nerve lesions.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS019523-06
Application #
3399599
Study Section
Neurology A Study Section (NEUA)
Project Start
1982-09-01
Project End
1988-09-24
Budget Start
1987-09-01
Budget End
1988-09-24
Support Year
6
Fiscal Year
1987
Total Cost
Indirect Cost
Name
Good Samaritan Hosp & Medical Center(Prtlnd,OR)
Department
Type
DUNS #
City
Portland
State
OR
Country
United States
Zip Code
97210
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Gladfelter, W E; Millecchia, R J; Pubols, L M et al. (1993) Crossed receptive field components and crossed dendrites in cat sacrocaudal dorsal horn. J Comp Neurol 336:96-105
Pubols, L M; Bernau, N A; Kane, L A et al. (1992) Distribution of 5-HT1 binding sites in cat spinal cord. Neurosci Lett 142:111-4
Millecchia, R J; Pubols, L M; Sonty, R V et al. (1991) Influence of map scale on primary afferent terminal field geometry in cat dorsal horn. J Neurophysiol 66:696-704
Pubols, L M; Simone, D A; Bernau, N A et al. (1991) Anesthetic blockade of the dorsolateral funiculus enhances evoked activity of spinal cord dorsal horn neurons. J Neurophysiol 66:140-52
Pubols, L M (1990) Characteristics of dorsal horn neurons expressing subliminal responses to sural nerve stimulation. Somatosens Mot Res 7:137-51
Pubols, L M; Bowen, D C (1988) Lack of central sprouting of primary afferent fibers after ricin deafferentation. J Comp Neurol 275:282-7
Pubols, L M; Foglesong, M E (1988) Acute and chronic effects of the neurolytic agent ricin on dorsal root ganglia, spinal cord, and nerves. J Comp Neurol 275:271-81
Pubols, L M; Hirata, H; Brown, P B (1988) Temporally dependent changes in response properties of dorsal horn neurons after dorsolateral funiculus lesions. J Neurophysiol 60:1253-67
Pubols, L M; Foglesong, M E; Vahle-Hinz, C (1986) Electrical stimulation reveals relatively ineffective sural nerve projections to dorsal horn neurons in the cat. Brain Res 371:109-22