| Project/Area Number |
15591645
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Anesthesiology/Resuscitation studies
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| Research Institution | Sapporo Medical University School of Medicine |
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Principal Investigator |
KAWAMATA Tomoyuki Sapporo Medical University School of Medicine, Department of Anesthesiology, Instructors, 医学部, 助手 (80336388)
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| Project Period (FY) |
2003 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2004: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2003: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | neurochemisitry / dorsal root ganglion cell / intracellular calcium / pain / endothelin-1 / capsaicin receptor / エンドセリン-1 / がん性疼痛 |
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| Research Abstract |
Background: Increasing evidence indicates that endothelin-1 (ET-1) has a role for peripheral nociceptive signaling in animals and humans. However, the mechanisms of the nociceptive effects of ET-1 have not been fully understood. The current study investigated the effects of ET-1 on the response of cultured adult mice dorsal root ganglion (DRG) neurons to capsaicin using intracellular calcium measurement and histochemical analyses.
Methods: DRG were harvested from adult male C57B6N mice and were cultured. With a digital image analysis system, we detected the [Ca^<2+>]_i image of cultured DRG cells after loading with fura-2 AM. In addition, co-localization of protein kinase C (PKCL) with transient receptor potential Vi (TRPV1) and the translocation of PKCD were investigated using immunohistochemical methods.
Results
ET-1 (10 nM) enhanced an increase in [Ca^<2+>]_i by capsaicin (10 nM) from 87.6 +- 11.6 nM to 414.8 +- 62.3 nM. The inhibition of endothelin A receptor significantly suppressed the enhancing effect of ET-1. In addition, a nonselective PKC inhibitor significantly suppressed the enhancing effect of ET-1. A myristoyl-tagged membrane-permeant-PKCD V1.2 inhibitory peptide also significantly suppressed the enhancing effect of ET-1. In the immunocytochemical study, PKCD immunoreactivity was found in most of TRPV1-positive neurons. After ET -1 application, PKCD immunoreactivity was observed to be translocated from the cytosol to the cell membrane in TRPV1-positive neurons,
Conclusion
Our results indicate that ET-1 enhances the response of DRG neurons to capsaicin in a PKC dependent manner. Our findings may lead to a new strategy to treat pain associated with ET-1.
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