The long-term objective of this research program is to understand the physiology of sympathetically dependent pain, such as that in reflex sympathetic dystrophy, acute herpes zoster and some cases of low back pain. The experiments proposed here focus upon trauma-induced changes in sympathetic activation of spinal neurons and deep-tissue afferents - trauma being a precipitating factor in many cases of sympathetically dependent pain.
Aim 1. To determine the effects of trauma on sympathetic activation of deep tissue primary afferents. Single unit recording in anesthetized cats will be used to characterize deep-tissue afferents responsive to sympathetic stimulation; to quantify trauma-induced changes in the responses of these afferents as a function of time subsequent to trauma; and to examine interactive effects of trauma and tonic sympathetic activity on the response characteristics of the afferents.
Aim 2. To determine the effects of deep-tissue trauma on sympathetically evoked activity in spinal neurons. Single unit recording from spinal neurons in anesthetized cats will be used to quantify traumainduced changes in the response characteristics of somatosensory neurons and to determine the combined effects of trauma and tonic sympathetic activity on the response properties of the neurons. Additional experiments will be done to differentiate central from peripheral effects induced by trauma on the responses of spinal neurons to sympathetic stimulation.
Aim 3. To determine which neurotransmitters in the periphery are responsible for sympathetic activation of spinal neurons and deep-tissue afferents. Sympathetic neurotransmitter antagonists will be systemically applied during single unit recording from functionally identified primary afferents and spinal neurons. Alterations in the responses of the afferents and neurons to sympathetic stimulation will be quantified.
Aim 4. To determine the topographical distributions of spinal neurons responsive to sympathetically-activated afferents from the hindlimb or to trauma-activated afferents from the low back. Immunocytochemistry will be used in anesthetized rats to label neurons that express c-fos. Expression will be induced by sympathetically evoked afferent activity after noxious conditioning stimulation in the hindlimb or by noxious stimulation of paraspinal tissues in the low back.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
2R01NS013447-10A1
Application #
3395172
Study Section
Neurological Sciences Subcommittee 1 (NLS)
Project Start
1978-01-01
Project End
1993-11-30
Budget Start
1990-12-01
Budget End
1991-11-30
Support Year
10
Fiscal Year
1991
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
Gillette, R G; Kramis, R C; Roberts, W J (1998) Suppression of activity in spinal nocireceptive 'low back' neurons by paravertebral somatic stimuli in the cat. Neurosci Lett 241:45-8
Gillette, R G; Kramis, R C; Roberts, W J (1994) Sympathetic activation of cat spinal neurons responsive to noxious stimulation of deep tissues in the low back. Pain 56:31-42
Gillette, R G; Kramis, R C; Roberts, W J (1993) Characterization of spinal somatosensory neurons having receptive fields in lumbar tissues of cats. Pain 54:85-98
Gillette, R G; Kramis, R C; Roberts, W J (1993) Spinal projections of cat primary afferent fibers innervating lumbar facet joints and multifidus muscle. Neurosci Lett 157:67-71
Roberts, W J; Foglesong, M E (1988) Spinal recordings suggest that wide-dynamic-range neurons mediate sympathetically maintained pain. Pain 34:289-304
Roberts, W J; Foglesong, M E (1988) Identification of afferents contributing to sympathetically evoked activity in wide-dynamic-range neurons. Pain 34:305-14
Roberts, W J; Elardo, S M (1986) Clustering of primary afferent fibers in peripheral nerve fascicles by sensory modality. Brain Res 370:149-52
Roberts, W J (1986) A hypothesis on the physiological basis for causalgia and related pains. Pain 24:297-311
Roberts, W J; Elardo, S M (1985) Sympathetic activation of A-delta nociceptors. Somatosens Res 3:33-44
Roberts, W J; Elardo, S M; King, K A (1985) Sympathetically induced changes in the responses of slowly adapting type I receptors in cat skin. Somatosens Res 2:223-36

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