Acute and chronic pain continue to be the most common complaints that physicians are asked to treat. While acute pain can be managed in most cases, the intense suffering in the cases that are currently difficult to treat demands a constant search for new methods of treatment with fewer side effects and risk of addiction. Chronic pain continues to be very difficult to treat with over $60 billion annually directly spent on treating this disorder. There problems stems from our incomplete understanding of the modulation of acute pain and mechanisms leading to chronic pain. In order for rational development of new therapies for the treatment of acute and chronic pain, it is essential to more thoroughly understand the synaptic, cellular, and molecular mechanisms by which transmission of nociceptive information is modified in the marginal zone (lamina I) and substantia gelatinosa (lamina II) of the spinal cord. This is long-term objective of this proposal. The suggested specific aims for the next 5-year period are: 1. To study how descending inputs modulate synaptic integration of laminae I and II neurons recorded in vivo. 2. To determine the physiological and morphological properties of inhibitory interneurons in laminae I and II recorded in vitro and confirmed in vivo. 3. To analyze the involvement of immediate early genes evoked by noxious stimulation on the long-term modulation of nociceptive behavior.
These specific aims will be accomplished by using rats for in vitro and in vivo whole-cell patch clamping techniques. Recordings will be combined with intracellular labeling so that the neuron and its dendritic and axonal arbor can be examined with the light and electron microscope. Putative neurotransmitters will be assessed using immunocytochemical techniques. Antisense oligonucleotide strategies will be combined with behavioral measurement of responses to noxious stimuli in rats to determine the importance of immediate early genes in mediating long-term changes in pain behavior.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS016433-20
Application #
6187535
Study Section
Neurology B Subcommittee 2 (NEUB)
Program Officer
Kitt, Cheryl A
Project Start
1980-07-01
Project End
2002-03-31
Budget Start
2000-04-01
Budget End
2002-03-31
Support Year
20
Fiscal Year
2000
Total Cost
$202,614
Indirect Cost
Name
University of North Carolina Chapel Hill
Department
Physiology
Type
Schools of Medicine
DUNS #
608195277
City
Chapel Hill
State
NC
Country
United States
Zip Code
27599
Eckert 3rd, William A; McNaughton, Kirk K; Light, Alan R (2003) Morphology and axonal arborization of rat spinal inner lamina II neurons hyperpolarized by mu-opioid-selective agonists. J Comp Neurol 458:240-56
Chattipakorn, Siriporn Chattipakorn; Sigurdsson, Asgeir; Light, Alan R et al. (2002) Trigeminal c-Fos expression and behavioral responses to pulpal inflammation in ferrets. Pain 99:61-9
Eckert 3rd, W A; Willcockson, H H; Light, A R (2001) Interference of biocytin with opioid-evoked hyperpolarization and membrane properties of rat spinal substantia gelatinosa neurons. Neurosci Lett 297:117-20
Fu, K Y; Light, A R; Maixner, W (2000) Relationship between nociceptor activity, peripheral edema, spinal microglial activation and long-term hyperalgesia induced by formalin. Neuroscience 101:1127-35
Chattipakorn, S C; Light, A R; Willcockson, H H et al. (1999) The effect of fentanyl on c-fos expression in the trigeminal brainstem complex produced by pulpal heat stimulation in the ferret. Pain 82:207-15
Light, A R; Willcockson, H H (1999) Spinal laminae I-II neurons in rat recorded in vivo in whole cell, tight seal configuration: properties and opioid responses. J Neurophysiol 82:3316-26
Vierck Jr, C J; Light, A R (1999) Effects of combined hemotoxic and anterolateral spinal lesions on nociceptive sensitivity. Pain 83:447-57
Madison, R D; Robinson, G A (1998) lambda RNA internal standards quantify sensitivity and amplification efficiency of mammalian gene expression profiling. Biotechniques 25:504-8, 510, 512, passim
Schneider, S P; Eckert 3rd, W A; Light, A R (1998) Opioid-activated postsynaptic, inward rectifying potassium currents in whole cell recordings in substantia gelatinosa neurons. J Neurophysiol 80:2954-62
Robinson, G A (1996) Changes in the expression of transcription factors ATF-2 and Fra-2 after axotomy and during regeneration in rat retinal ganglion cells. Brain Res Mol Brain Res 41:57-64

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