During the last five years of NIH funding, we have made significant progress in accomplishing the specific aims outlined in the original research project. The findings summarized in the Progress Report indicate three major lines of interactions between the spinal cord N-methyl-D-aspartate (NMDA) and opioid receptor systems in relation to hyperalgesia and opioid tolerance. Moreover, these findings reveal potentially irreversible degenerative neuronal changes associated with hyperalgesia and opioid tolerance. Since NMDA and opioid receptors represent two important systems in nociception-related neuroplasticity and antinociception, the goal of this competing grant renewal is to continue the fruitful work carried out over the last funding period and to further investigate neural and molecular mechanisms of interactions between these two receptor systems. Multidisciplinary approaches including behavioral, pharmacological, and immunocytochemical methods will be used to accomplish three specific aims: (1) To examine co-localization of NMDA and p-opioid receptors in spinal cord neurons and to determine the topographic distribution of such co-localization in rats with and without hyperalgesia or mu-opioid tolerance; (2) To examine the nature of degenerative neuronal changes in the spinal cord associated with hyperalgesia and p-opioid tolerance and to explore the time course and dose-response relationship of opioid treatment with the occurrence of degenerative neuronal changes; and (3) To determine the role of NMDA receptor activation and related intracellular changes in degenerative neuronal changes associated with p-opioid tolerance. This proposed work is a logical continuation of previous studies, which will provide novel and important information on cellular and intracellular interactions between NMDA and p-opioid receptors and on the role of such interactions in hyperalgesia and p-opioid tolerance. Thus, the results from this work may help improve the clinical utility of opioid analgesics in treating cancer and chronic pain syndromes. Importantly, investigations of opioid-induced degenerative neuronal changes and their relation to pathophysiological pain states may provide insights into the neurobiology of both hyperalgesia and opioid tolerance, which could result in additional clinical applications.

Agency
National Institute of Health (NIH)
Institute
National Institute on Drug Abuse (NIDA)
Type
Research Project (R01)
Project #
5R01DA008835-10
Application #
6895926
Study Section
Integrative, Functional and Cognitive Neuroscience 8 (IFCN)
Program Officer
Lin, Geraline
Project Start
1995-04-01
Project End
2007-04-30
Budget Start
2005-05-01
Budget End
2007-04-30
Support Year
10
Fiscal Year
2005
Total Cost
$346,000
Indirect Cost
Name
Massachusetts General Hospital
Department
Type
DUNS #
073130411
City
Boston
State
MA
Country
United States
Zip Code
02199
Shen, Shiqian; Lim, Grewo; You, Zerong et al. (2017) Gut microbiota is critical for the induction of chemotherapy-induced pain. Nat Neurosci 20:1213-1216
Yang, Liling; Wang, Shuxing; Sung, Backil et al. (2008) Morphine induces ubiquitin-proteasome activity and glutamate transporter degradation. J Biol Chem 283:21703-13
Sung, Backil; Wang, Shuxing; Zhou, Bei et al. (2007) Altered spinal arachidonic acid turnover after peripheral nerve injury regulates regional glutamate concentration and neuropathic pain behaviors in rats. Pain 131:121-31
Wang, Shuxing; Lim, Grewo; Mao, Ji et al. (2007) Central glucocorticoid receptors regulate the upregulation of spinal cannabinoid-1 receptors after peripheral nerve injury in rats. Pain 131:96-105
Wang, Shuxing; Lim, Grewo; Yang, Liling et al. (2006) Downregulation of spinal glutamate transporter EAAC1 following nerve injury is regulated by central glucocorticoid receptors in rats. Pain 120:78-85
Lim, Jeongae; Lim, Grewo; Sung, Backil et al. (2006) Intrathecal midazolam regulates spinal AMPA receptor expression and function after nerve injury in rats. Brain Res 1123:80-8
Lim, Grewo; Wang, Shuxing; Mao, Jianren (2005) Central glucocorticoid receptors modulate the expression of spinal cannabinoid receptors induced by chronic morphine exposure. Brain Res 1059:20-7
Lim, Grewo; Wang, Shuxing; Zeng, Qing et al. (2005) Expression of spinal NMDA receptor and PKCgamma after chronic morphine is regulated by spinal glucocorticoid receptor. J Neurosci 25:11145-54
Mao, Jianren (2005) Glutamate transporter: an unexpected target for some antibiotics. Mol Pain 1:5
Lim, Grewo; Wang, Shuxing; Zeng, Qing et al. (2005) Evidence for a long-term influence on morphine tolerance after previous morphine exposure: role of neuronal glucocorticoid receptors. Pain 114:81-92

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