Neuroscience research
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Neuroscience research · Jul 2007
Involvement of substance P and calcitonin gene-related peptide in development and maintenance of neuropathic pain from spinal nerve injury model of rat.
Recently, it has been suggested that uninjured primary sensory neurons contribute to neuropathic pain induced by peripheral nerve injury. However, there is lack of evidences of roles of normal pain transmitting substances such as substance P and calcitonin gene-related peptide (CGRP) in neuropathic pain. Whether substance P and CGRP have a role in spinal nerve-injured neuropathic pain model was tested. ⋯ The treatments with lidocaine, L703,606 and CGRP8-37 delayed the onset of neuropathic pain by 1-4 days, compared with the saline-treated rats. After neuropathic pain was established, intrathecal injections of L703,606 and CGRP8-37 significantly mitigated mechanical hyperalgesia for 20 min. These results suggest that substance P and CGRP are involved in the development and maintenance of neuropathic pain and that these peptides from the central terminals of intact sensory neurons contribute to the maintenance of peripheral nerve injury-induced neuropathic pain.