| mRNA of sensory neuron-specific receptor (SNSR) is uniquely located in the small diameter neurons in dorsal root ganglia (DRG) and trigeminal ganglia (TG).It has been demonstrated that intermittent administration of bovine adrenal medulla8-22(BAM8-22),a selective SNSR agonist,can inhibit the sciatic nerve ligation-induced hyperalgesia. However, activate SNSR whether to participate modulating pain in the other neuropathic pain model as well as its modulation mechanism is unclear.Adrenomedullin2belongs to the calcitonin family and shares the similarities in structure and function with calcitonin gene related peptide(CGRP) and Adrenomedullin (AM). It has been demonstrated that AM and CGRP participate in the formation and maintenance of pain. But in the pathological state of Pain, whether AM2have the same function with AM and CGRP, whether associated with pain, is unclear.This study was conducted using behavioral and immunohistochemical. We first examined the AM2expression in DRG neurons after injection CFA on the plantar induced inflammation pain.The results showed that:The distribution of AM2large, medium and small positive neurons in L4-L6DRG have no significant difference between the control group. Intrathecal injection of BAM8-22can reduce the hyperalgesia after L5spinal nerve ligation. And there is a dose-dependent effect, the higher the concentration, the recovery effect is more obvious. The expression of adrenomedullin2in L4dorsal root ganglion were increased following the surgery of SNL. However, injection of the sensory neuron-specific receptor agonist BAM8-22, but not saline, can abolished the increase of adrenomedullin2in L4DRG. These results in present study suggest that AM2may be involved in the maintenance of neuropathic pain, and apply BAM8-22to activate the SNSR can inhibit the increase of AM2, so as to reduce the hyperalgesia of the spinal nerve ligation rats. |
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