(taken from the application): Although 14% of the United States population suffers from chronic musculoskeletal pain, most of our knowledge about pain has been obtained from studies on cutaneous pain. The current models of musculoskeletal pain typically produce short term hyperalgesia (resolved in 24 h or less). However, clinically, chronic muscle pain, as experienced by people with fibromyalgia, is long lasting (months to years). In preliminary studies, I determined that a long lasting bilateral hyperalgesia can be induced by two injections of low pH saline, five days apart, into one gastrocnemius muscle. In the work proposed I hypothesize that the development of the long lasting bilateral hyperalgesia is dependent initially on input from the site of injection following both the first and second injection. I further propose that once the long lasting hyperalgesia develops plastic changes in the central nervous system occur that maintain the hyperalgesia through increased activity in spinal neurons.
The specific aims will establish and characterize a new model of muscle pain that is chronic and widespread. The proposed studies will establish if the neural mechanisms involved in the development and maintenance of chronic pain, induced by stimulation of muscle nociceptors, involve peripheral or central nervous system processes. These proposed studies will help in the understanding and thus potential treatment of chronic muscle pain, including such conditions as fibromyalgia, myofascial pain and low back pain.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS039734-04
Application #
6540220
Study Section
Special Emphasis Panel (ZAR1-BHD-B (J1))
Program Officer
Porter, Linda L
Project Start
1999-07-26
Project End
2004-02-29
Budget Start
2002-07-01
Budget End
2003-06-30
Support Year
4
Fiscal Year
2002
Total Cost
$173,692
Indirect Cost
Name
University of Iowa
Department
Miscellaneous
Type
Schools of Medicine
DUNS #
041294109
City
Iowa City
State
IA
Country
United States
Zip Code
52242
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Skyba, D A; Lisi, T L; Sluka, K A (2005) Excitatory amino acid concentrations increase in the spinal cord dorsal horn after repeated intramuscular injection of acidic saline. Pain 119:142-9
Skyba, David A; Radhakrishnan, Rajan; Sluka, Kathleen A (2005) Characterization of a method for measuring primary hyperalgesia of deep somatic tissue. J Pain 6:41-7
Radhakrishnan, Rajan; King, Ellen W; Dickman, Janelle K et al. (2003) Spinal 5-HT(2) and 5-HT(3) receptors mediate low, but not high, frequency TENS-induced antihyperalgesia in rats. Pain 105:205-13
Hoeger-Bement, Marie K; Sluka, Kathleen A (2003) Phosphorylation of CREB and mechanical hyperalgesia is reversed by blockade of the cAMP pathway in a time-dependent manner after repeated intramuscular acid injections. J Neurosci 23:5437-45

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