Background: Calcitonin is used as a treatment to reduce the blood calcium concentration in hypercalcemia and to improve bone mass in osteoporosis. An analgesic effect of calcitonin has been observed and reported in clinical situations. Ovariectomaized (OVX) rats exhibit the same hormonal changes as observed in humans with osteoporosis and are an animal model of postmenopousal osteoporosis. The aim of this study to investigate antinociceptive effect of calcitonin in OVX rats using the immunohistochemical study.

Mechanical and chemical factors caused altered gene expression in the DRG at 7 days after surgery, suggesting that the mechanisms of nerve injury induced by these factors differ. The upregulation of IGF-1 might be a key factor in painful radiculopathy induced by mechanical factors.

IGF-1 was localized particularly in the neuronal cell body, and revealed that it colocalized with NeuN but not with glial fibrillary acidic protein. The threshold was reduced in the vehicle and siRNA groups compared with the sham group. The threshold of the siRNA group significantly recovered from reduction compared with the vehicle group at 5 days after surgery, and this effect persisted throughout the experimental period. CONCLUSION.: IGF-1 was localized with neuronal cell bodies in DRG. IGF-1 knockdown caused a reduction in mechanical allodynia. The upregulation of IGF-1 might be a key factor in painful radiculopathy induced by mechanical factors.

Background: Reduction of blood flow is important in the induction of neurogenic intermittent claudication (NIC) in lumbar spinal canal stenosis. PGE 1 improves the mean walking distance in patients with NIC type cauda equina compression. PGE 1 derivate might be effective in dilating blood vessels and improving blood flow in nerve roots with chronically compressed cauda equina. The aim of this study was to assess whether PGE 1 derivate has vasodilatory effects on both arteries and veins in a canine model of chronic cauda equina compression.