Analgesic effect of intrathecal administration of orexin on neuropathic pain in rats.
Orexin-A, a hypothalamic peptide found in the neurons of the lateral hypothalamus, has been shown to modulate pain. We examined whether orexin could alleviate heat-evoked hyperalgesia in rats caused by chronic constriction injury (CCI) of the sciatic nerve. Orexin-A, orexin-B, the vehicle, or orexin-A-antiserum was intrathecally administered to CCI rats. Paw withdrawal latency (PWL) was measured from 30 to 300 minutes after injection, which was repeated for 2 days. Orexin-A administration normalized deltaPWL (PWL in the CCI side minus PWL in the control side) and inhibited heat-evoked hyperalgesia in CCI rats, while orexin-A antiserum inhibited the normalization of heat-evoked hyperalgesia caused by orexin-A two-fold. In contrast, orexin-B had no significant effect. These results suggest that orexin-A may be applicable for treatment of neuropathic pain.
Suyama
Hidemichi
H
Department of Anesthesiology and Critical Care, Graduate School of Biomedical Sciences, Hiroshima University, Japan.
Kawamoto
Masashi
M
Shiraishi
Seiji
S
Gaus
Syafruddin
S
Kajiyama
Seiji
S
Yuge
Osafumi
O
D000700:Analgesics / Q000008:administration & dosage / Q000627:therapeutic use*; D000818:Animals; D002352:Carrier Proteins / Q000008:administration & dosage / Q000627:therapeutic use*; D004195:Disease Models, Animal; D006358:Hot Temperature; D006930:Hyperalgesia / Q000188:drug therapy* / Q000209:etiology; D007278:Injections, Spinal; D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides / Q000008:administration & dosage / Q000627:therapeutic use*; D000068797:Orexins; D010146:Pain / Q000188:drug therapy* / Q000503:physiopathology; D051381:Rats; D020426:Sciatic Neuropathy / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology
D000700:Analgesics; D002352:Carrier Proteins; D047908:Intracellular Signaling Peptides and Proteins; D009479:Neuropeptides; D000068797:Orexins