Recent study has shown that rapamycin, a tool for the study of the Akt/mTOR signaling pathway, can effectively reduce the mechanical sensitivity of rats with chronic inflammatory pain. After pretreatment with rapamycin, the late maintenance of long-term potentiation and long-term memory formation in the hippocampus were blocked, and the hyperalgesia induced by formalin was reduced; moreover, the excitability of spinal dorsal horn
neurons was also significantly decreased., To better understand, the effect of rapamycin on neuropathic pain, we applied rapamycin to stavudine-treated mice to further explore the role of rapamycin in hyperthermia and mechanical pain abnormalities.
Koumine Reduces the Production of Cytokines in the Spinal Dorsal Horn
of CCI Rats.
Both TLR4 and CXCR4 are abundant in glial cells in superficial dorsal horn
in the spinal cord, which are important sensory regulation center that are closely related to the occurrence of neuropathic pain .
The right spinal dorsal horns
from L4-L6 were exposed, rapidly separated, and then stored in a -80[degrees]C freezer.
It also reported that PDGF expressed in dorsal horn
neurons contributes to neuropathic pain after nerve injury, (22) though how PDGF produces pain hypersensitivity remains unknown.
Hathway, "Postnatal maturation of endogenous opioid systems within the periaqueductal grey and spinal dorsal horn
of the rat," Pain, vol.
Briefly, SigmaScan Pro software (SPSS) was used to overlay a grid with squares measuring 10000 [micro][m.sup.2] on regions of the dorsal horn
. A minimum of 5 randomly selected squares from a minimum of 4 spinal cord sections per animal were analysed.
Our results showed that application of NP onto the dorsal nerve roots within minutes increased the C-fiber response in the dorsal horn
. The changes in gene expression in the DRG suggest that the primary afferent nerve fibers may be affected by NP.
Abbreviations CFA: The complete Freund adjuvant COX-2: Cyclooxygenase-2 EA: Electroacupuncture Gi: The gigantocellular reticular nucleus GiA: The gigantocellular reticular nucleus pars alpha IL-1: Interleukin-1 MAPK: Mitogen-activated protein kinase NRM: The nucleus raphe magnus PAG: The periaqueductal gray p-p38MAPK: Phosphorylated p38MAPK p-p38MAPK-IR: Phosphor-p38MAPK-Immunoreactivity PWT: Paw withdrawal threshold RVM: Rostral ventromedial medulla SCDH: Spinal cord dorsal horn
vlPAG: Ventrolateral periaqueductal gray.
Therefore, it can be considered that the Curcumin has the ability to modulate the activity in the primary afferent fibers induced by formalin in phase I and to reduce the activation of wide dynamic range neurons in dorsal horn
. The hyperactivity of wide dynamic range neurons which represents a facilitated pain state, despite reduction of pain stimuli, is a feature of phase II of formalin test .
After the images were captured, the optical density (OD) of GFAP or the number of p-CERB positive neurons in the same areas of the ipsilateral superficial dorsal horn
(laminae I and II) was calculated and averaged across the five spinal sections for each rats.