Rho-kinase mediates spinal nitric oxide formation by prostaglandin E2 via EP3 subtype.
Prostaglandin E2 (PGE2), the principal pro-inflammatory prostanoid, is known to play versatile roles in pain transmission via four PGE receptor subtypes, EP1-EP4. We recently demonstrated that continuous production of nitric oxide (NO) by neuronal NO synthase (nNOS) following phosphorylation of myristoylated alanine-rich C-kinase substrate (MARCKS) and NMDA receptor NR2B subunits is essential for neuropathic pain. These phosphorylation and nNOS activity visualized by NADPH-diaphorase histochemistry were blocked by indomethacin, a PG synthesis inhibitor. To clarify the interaction between cyclooxygenase and nNOS pathways in the spinal cord, we examined the effect of EP subtype-selective agonists on NO production. NO formation was stimulated in the spinal superficial layer by EP1, EP3, and EP4 agonists. While the EP1- and the EP4-stimulated NO formation was markedly blocked by MK-801, an NMDA receptor antagonist, the EP3-stimulated one was completely inhibited by H-1152, a Rho-kinase inhibitor. Phosphorylation of MARCKS and NADPH-diaphorase activity stimulated by the EP3 agonist were also blocked by H-1152. These results suggest that PGE2 stimulates NO formation by Rho-kinase via EP3, a mechanism(s) different from EP1 and EP4.
Matsumura
Shinji
S
Department of Medical Chemistry, Kansai Medical University, Moriguchi 570-8506, Japan.
Abe
Tetsuya
T
Mabuchi
Tamaki
T
Katano
Tayo
T
Takagi
Kunio
K
Okuda-Ashitaka
Emiko
E
Tatsumi
Shinichi
S
Nakai
Yoshihide
Y
Hidaka
Hiroyoshi
H
Suzuki
Masaaki
M
Sasaki
Yasuharu
Y
Minami
Toshiaki
T
Ito
Seiji
S
D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology; D015232:Dinoprostone / Q000502:physiology*; D007213:Indomethacin / Q000494:pharmacology; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D000076250:Myristoylated Alanine-Rich C Kinase Substrate; D009569:Nitric Oxide / Q000096:biosynthesis*; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000737:chemistry* / Q000502:physiology; D018078:Receptors, Prostaglandin E / Q000819:agonists / Q000502:physiology*; D058308:Receptors, Prostaglandin E, EP3 Subtype; D013116:Spinal Cord / Q000201:enzymology* / Q000378:metabolism; D054460:rho-Associated Kinases
D000894:Anti-Inflammatory Agents, Non-Steroidal; D047908:Intracellular Signaling Peptides and Proteins; C000619711:Marcks protein, mouse; D008565:Membrane Proteins; C545648:Ptger3 protein, mouse; D018078:Receptors, Prostaglandin E; D058308:Receptors, Prostaglandin E, EP3 Subtype; D000076250:Myristoylated Alanine-Rich C Kinase Substrate; D009569:Nitric Oxide; D017346:Protein Serine-Threonine Kinases; D054460:rho-Associated Kinases; D015232:Dinoprostone; D007213:Indomethacin