Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0423716 (Neuropathic pain)
 1,417 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Neuropathic pain states are accompanied by increased sensitivity to both noxious and non-noxious sensory stimuli, characterized as hyperalgesia and allodynia, respectively. In animal models of neuropathic pain, the presence of hyperalgesia and allodynia are accompanied by neuroplastic changes including increased spinal levels of substance P, cholecystokinin (CCK), and dynorphin. N-Methyl-D-aspartate (NMDA) receptors appear to be involved in maintaining the central sensitivity which contributes to neuropathic pain. In addition to its opioid activities, dynorphin has been suggested to act at the NMDA receptor complex. In an attempt to mimic the increased levels of spinal dynorphin seen in animal models of neuropathic pain, rats received a single intrathecal (i.t.) injection of dynorphin A(1-17), dynorphin A(1-13), dynorphin A(2-17) or dynorphin A(2-13) through indwelling catheters. Tactile allodynia was determined by measuring response threshold to probing with von Frey filaments. Dynorphin A(1-17) administration evoked significant and long-lasting tactile allodynia (i.e. > 60 days). Likewise, the i.t. administration of dynorphin A(1-13) or dynorphin A(2-17) or dynorphin A(2-13) also produced long-lasting tactile allodynia. Intrathecal pretreatment, but not post-treatment, with MK-801 prevented dynorphin A(1-17)-induced development of allodynia; i.t. administration of MK-801 alone had no effect on responses to tactile stimuli. In contrast, i.t. pretreatment with naloxone did not affect the development of tactile allodynia induced by dynorphin A(1-17) or alter sensory threshold when given alone. These results demonstrate that a single dose of dynorphin A, or its des-Tyr fragments, produces long-lasting allodynia which may be irreversible in the rat. Further, this effect appears to be mediated through activation of NMDA, rather than opioid, receptors. While the precise mechanisms underlying the development and maintenance of the allodynia is unclear, it seems possible that dynorphin may produce changes in the spinal cord, which may contribute to the development of signs reminiscent of a "neuropathic' state. Given that levels of dynorphin are elevated following nerve injury, it seems reasonable to speculate that dynorphin may have a pathologically relevant role in neuropathic pain states.
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PMID:Single intrathecal injections of dynorphin A or des-Tyr-dynorphins produce long-lasting allodynia in rats: blockade by MK-801 but not naloxone. 912 15

Neuropathic pain states and tolerance to opioids can result from system changes in the CNS, such as up-regulation of the NK1 receptor and substance P, lead to antiopioid effects in ascending or descending pain-signaling pathways. Bifunctional compounds, possessing both the NK1 antagonist pharmacophore and the opioid agonist pharmacophore with delta-selectivity, could counteract these system changes to have significant analgesic efficacy without undesirable side effects. As a result of the introduction of cyclic and topological constraints with penicillamines, 2 (Tyr-cyclo[d-Pen-Gly-Phe-Pen]-Pro-Leu-Trp-NH-[3',5'-(CF(3))(2)-Bzl]) was found as the best bifunctional compound with effective NK1 antagonist and potent opioid agonist activities, and 1400-fold delta-selectivity over the mu-receptor. The NMR structural analysis of 2 revealed that the relative positioning of the two connected pharmacophores as well as its cyclic and topological constraints might be responsible for its excellent bifunctional activities as well as its significant delta-opioid selectivity. Together with the observed high metabolic stability, 2 could be considered as a valuable research tool and possibly a promising candidate for a novel analgesic drug.
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PMID:Biological and conformational evaluation of bifunctional compounds for opioid receptor agonists and neurokinin 1 receptor antagonists possessing two penicillamines. 2061 91

Protein tyrosine phosphatase 1B (PTP1B) has been shown to dephosphorylate and inactivate insulin receptors, which contributes to the pathogenesis of diabetes. Neuropathic pain is one of the severe complications that results from diabetic neuropathy. However, whether PTP1B was involved in the development of diabetic neuropathic pain is largely unknown. The current study illustrated that PTP1B was located in spinal cord dorsal horn neurons of Sprague-Dawley rats. Western blot analysis demonstrated that the diabetic neuropathic pain induced by intraperitoneal injection of streptozotocin was associated with an increased protein expression and a dynamic redistribution of spinal PTP1B into excitatory glutamatergic synapses. We found that PTP1B operated to stimulate Src kinase and enhance the tyrosine phosphorylation of N-methyl-D-aspartate (NMDA) subtype of glutamate receptors. The siRNA-mediated knockdown of PTP1B in streptozotocin-injected rats repressed Src activity, decreased NMDA receptor phosphorylation and alleviated the thermal hyperalgesia and mechanical allodynia. A similar analgesia against diabetic neuropathic pain was also achieved when PTP1B activity was manipulated by a chemical PTP Inhibitor or PTP1B(C215S) mutant. These data revealed a regulated expression of PTP1B in spinal cord dorsal horn of rats after diabetic neuropathy, and demonstrated that inhibition of PTP1B was beneficial for the treatment of pain hypersensitivity related to diabetes.
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PMID:Inhibition of protein tyrosine phosphatase 1B in spinal cord dorsal horn of rats attenuated diabetic neuropathic pain. 2952 16