Inflammatory pain is a very common clinical phenomenon that causes great individual suffering and expense to society. Some of the most severe forms of pain, particularly chronic inflammatory pains, are partly or wholly intractable to currently available therapies. The investigators have shown that the cAMP/PKA second messenger pathway plays a major role in hyperalgesia induced by prostaglandin E2 (PGE2) and recently that nitric oxide (NO) also contributes via a guanylyl cyclase-independent mechanism. They now propose to study the cellular mechanism(s) underlying an additional novel action of NO, guanylyl cyclase-dependent hyperalgesia. They will also investigate the role of PKCepsilon in hyperalgesia and nociceptor sensitization produced by other inflammatory mediators. The investigators will also study mechanisms of mechanical transduction in nociceptors. They have recently been able to demonstrate a mechanically-induced whole cell current in cultured dorsal root ganglion neurons. They propose to fully characterize this current in order to establish an in vitro electrophysiological model for the study of nociception of mechanical stimuli. The investigators will also investigate changes in second messenger pathways involved in chronic hyperalgesia, focusing on a novel phenomenon they recently discovered in which the hyperalgesic response to an inflammatory mediator is enhanced for a period of weeks following recovery from the inflammatory hyperalgesic state. These experiments should provide significant novel information about mechanisms of inflammatory pain and hyperalgesia and cellular mechanisms of mechanical transduction in primary afferent neurons that may be important in chronic pain states in humans. These investigations should yield insights into potential pharmacological targets for the treatment of chronic inflammatory pain.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS021647-15
Application #
6187531
Study Section
Special Emphasis Panel (ZRG1-IFCN-4 (01))
Program Officer
Kitt, Cheryl A
Project Start
1985-07-01
Project End
2002-03-31
Budget Start
2000-04-01
Budget End
2001-03-31
Support Year
15
Fiscal Year
2000
Total Cost
$264,044
Indirect Cost
Name
University of California San Francisco
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
073133571
City
San Francisco
State
CA
Country
United States
Zip Code
94143
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Chen, Xiaojie; Levine, Jon D (2007) Mechanically-evoked C-fiber activity in painful alcohol and AIDS therapy neuropathy in the rat. Mol Pain 3:5
Chen, Xiaojie; Levine, Jon D (2005) Epinephrine-induced excitation and sensitization of rat C-fiber nociceptors. J Pain 6:439-46
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Joseph, E K; Levine, J D (2003) Sexual dimorphism in the contribution of protein kinase C isoforms to nociception in the streptozotocin diabetic rat. Neuroscience 120:907-13
Parada, C A; Yeh, J J; Reichling, D B et al. (2003) Transient attenuation of protein kinase Cepsilon can terminate a chronic hyperalgesic state in the rat. Neuroscience 120:219-26
Chen, X; Levine, J D (2003) Altered temporal pattern of mechanically evoked C-fiber activity in a model of diabetic neuropathy in the rat. Neuroscience 121:1007-15
Shin, Jieun; Cho, Hawon; Hwang, Sun Wook et al. (2002) Bradykinin-12-lipoxygenase-VR1 signaling pathway for inflammatory hyperalgesia. Proc Natl Acad Sci U S A 99:10150-5
Dina, O A; Aley, K O; Isenberg, W et al. (2001) Sex hormones regulate the contribution of PKCepsilon and PKA signalling in inflammatory pain in the rat. Eur J Neurosci 13:2227-33
Aley, K O; Martin, A; McMahon, T et al. (2001) Nociceptor sensitization by extracellular signal-regulated kinases. J Neurosci 21:6933-9

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