Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0030193 (pain)
 261,466 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The peptide neurotransmitter substance P modulates sensitivity to pain by activating the neurokinin-1 (NK-1) receptor, which is expressed by discrete populations of neurons throughout the central nervous system. Substance P is synthesized by small-diameter sensory 'pain' fibres, and release of the peptide into the dorsal horn of the spinal cord following intense peripheral stimulation promotes central hyperexcitability and increased sensitivity to pain. However, despite the availability of specific NK-1 antagonists, the function of substance P in the perception of pain remains unclear. Here we investigate the effect of disrupting the gene encoding the NK-1 receptor in mice. We found that the mutant mice were healthy and fertile, but the characteristic amplification ('wind up') and intensity coding of nociceptive reflexes was absent. Although substance P did not mediate the signalling of acute pain or hyperalgesia, it was essential for the full development of stress-induced analgesia and for an aggressive response to territorial challenge, demonstrating that the peptide plays an unexpected role in the adaptive response to stress.
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PMID:Altered nociception, analgesia and aggression in mice lacking the receptor for substance P. 953 17

The neuropeptide substance P binds to the G protein-coupled neurokinin-1 (NK-1) receptor and elicits cellular responses thought to be involved in pain, neurogenic inflammation, vasodilatation, and plasma exudation. Several small molecule nonpeptide antagonists of the substance P/NK-1 receptor interaction have been developed. Mutational analysis of the receptor protein sequence has led to the conclusion that the binding site for these nonpeptide antagonists lies within the bundle created by transmembrane domains IV-VII of the receptor. This current investigation employs site directed mutagenesis of the NK-1 receptor to compare the binding site of CP-96,345 with that of a related compound CP-99,994. The data demonstrate that while both compounds appear to bind within the transmembrane domain bundle, the contribution of individual amino acid residues to the binding of each compound differs.
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PMID:Two related neurokinin-1 receptor antagonists have overlapping but different binding sites. 954 42

Severe traumatic injuries and infections are frequently accompanied by life-threatening shock and are associated with increases in the proinflammatory cytokines, particularly tumor necrosis factor alpha (TNF-alpha). The body's first perception of injury is the nociceptive or pain response. This response is induced at the site of injury and is transmitted systemically by sensory neuropeptides, the tachykinins, released from sensory afferent c-fiber neurons. We studied the role of tachykinins in regulating the production of proinflammatory cytokines induced by the administration of bacterial lipopolysaccharide. Destruction of terminal sensory nerve endings before lipopolysaccharide administration abrogates tachykinin synthesis and down-regulates TNF-alpha transcription and secretion. In contrast, the responses of interleukins-1 and -6 are unaffected. Pretreating animals with an antagonist for the substance P-specific NK-1 receptor also down-regulated the TNF-alpha response, whereas blockade of the NK-2 receptor had no effect. These findings indicate that substance P contributes to the induction of those cytokines that are involved in precipitating the shock response.
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PMID:Neuropeptide regulation of proinflammatory cytokine responses. 958 4

This study evaluated the short-term outcome of primary total knee replacement, using standard and reliable outcome measures, for osteoarthritis in an Australian population. This study also compared the pre-operative health status of the patient population with population norms using a quality of life questionnaire. Using the medical outcome study (MOS) 36-item short form health survey (SF-36), there was a statistically significant improvement in physical functioning and bodily pain in males and bodily pain, vitality, role-emotional and mental health in females (P < 0.05). A statistically significant improvement was also seen in Knee Society Scores following surgery for both males and females (P < 0.05). Comparison of pre-operative SF-36 data to age-matched Australian normative values demonstrate that female patients requiring total knee replacement were significantly below the norms in virtually all health dimensions while males were significantly below the norms in mainly physical health dimensions (P < 0.01).
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PMID:Primary total knee replacement: short-term outcomes in an Australian population. 963 51

The generation of knock-out and transgenic mice offers a promising approach to the identification of novel biochemical factors that contribute to persistent pain conditions. To take advantage of these mice, however, it is important to demonstrate that the traditional models of persistent pain, which were largely developed for studies in the rat, can be used in the mouse. Here, we combined behavioral and anatomical methods to characterize the pathophysiology of a partial nerve injury-evoked pain condition in the 'normal' mouse. In male C57BL6 mice we tied a tight ligature around 1/3 to 1/2 of the diameter of the sciatic nerve and evaluated the time-course and magnitude of the ensuing mechanical and thermal allodynia. We also used immunocytochemistry to analyze nerve injury-induced changes in substance P (SP) and NK-1 (SP) receptor expression in the spinal cord. As in the rat, partial nerve injury markedly decreased paw withdrawal thresholds to both mechanical and thermal stimuli on the injured side. We detected threshold changes one day after the injury. The thermal allodynia resolved by 49 days, but the mechanical allodynia persisted for the duration of the study (70 days). We found no changes contralateral to the nerve injury. Sympatholytic treatment with guanethidine significantly reduced both the thermal and mechanical allodynia. We observed a reduction of SP immunoreactivity in the superficial dorsal horn on the injured side at 7 and 14, but not at 3 or 70 days after the nerve injury, and we observed an increase of NK-1 receptor expression at 3, 7, 14 and 42, but not at 70 days after the injury. We conclude that partial injury to the sciatic nerve produces a comparable allodynia and neurochemical plasticity in the rat and mouse. These results establish a valuable model for future studies of the biochemical basis of neuropathic pain in mice with specific gene modifications.
Pain 1998 May
PMID:Partial sciatic nerve injury in the mouse as a model of neuropathic pain: behavioral and neuroanatomical correlates. 969 76

Structural modifications requiring novel synthetic chemistry were made to the morpholine acetal human neurokinin-1 (hNK-1) receptor antagonist 4, and this resulted in the discovery of 2-(R)-(1-(R)-3, 5-bis(trifluoromethyl)phenylethoxy)-3-(S)-(4-fluoro)phenyl-4-(3-ox o-1 ,2,4-triazol-5-yl)methyl morpholine (17). This modified compound is a potent, long-acting hNK-1 receptor antagonist as evidenced by its ability to displace [125I]Substance P from hNK-1 receptors stably expressed in CHO cells (IC50 = 0.09 +/- 0.06 nM) and by the measurement of the rates of association (k1 = 2.8 +/- 1.1 x 10(8) M-1 min-1) and dissociation (k-1 = 0.0054 +/- 0.003 min-1) of 17 from hNK-1 expressed in Sf9 membranes which yields Kd = 19 +/- 12 pM and a t1/2 for receptor occupancy equal to 154 +/- 75 min. Inflammation in the guinea pig induced by a resiniferatoxin challenge (with NK-1 receptor activation mediating the subsequent increase in vascular permeability) is inhibited in a dose-dependent manner by the oral preadmininstration of 17 (IC50 (1 h) = 0.008 mg/kg; IC90 (24 h) = 1.8 mg/kg), indicating that this compound has good oral bioavailbility and peripheral duration of action. Central hNK-1 receptor stimulation is also inhibited by the systemic preadministration of 17 as shown by its ability to block an NK-1 agonist-induced foot tapping response in gerbils (IC50 (4 h) = 0.04 +/- 0.006 mg/kg; IC50 (24 h) = 0.33 +/- 0.017 mg/kg) and by its antiemetic actions in the ferret against cisplatin challenge. The activity of 17 at extended time points in these preclinical animal models sets it apart from earlier morpholine antagonists (such as 4), and the piperidine antagonists 2 and 3 and could prove to be an advantage in the treatment of chronic disorders related to the actions of Substance P. In part on the basis of these data, 17 has been identified as a potential clinical candidate for the treatment of peripheral pain, migraine, chemotherapy-induced emesis, and various psychiatric disorders.
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PMID:Structural optimization affording 2-(R)-(1-(R)-3, 5-bis(trifluoromethyl)phenylethoxy)-3-(S)-(4-fluoro)phenyl-4- (3-oxo-1,2,4-triazol-5-yl)methylmorpholine, a potent, orally active, long-acting morpholine acetal human NK-1 receptor antagonist. 980

The substance P receptor neurokinin-1 is expressed by a subset of neurons in the rat spinal cord. We have combined immunostaining for Fos, a marker of noxious peripheral stimulation, and neurokinin-1 to examine whether nociceptive signals from particular peripheral tissues (skin, muscle or knee joint) or activity generated by nerve injury or formalin-induced inflammation are preferentially modulated by substance P. Our results indicate that superficial and deep spinal neurokinin-1-positive neurons process nociceptive information in markedly different ways. In lamina I, the number of double-labelled neurons was positively correlated with the intensity of the stimulus (defined by the total Fos count) and was not directly related to any particular peripheral target. However, in the deeper layers of the spinal cord (V-X), there was no such correlation, and stimulation of joint nociceptors and formalin-induced inflammation produced the greatest proportion of Fos/neurokinin-1 co-localization, suggesting a particular role for substance P in the mediation of joint pain and inflammatory hyperalgesia. Thus, lamina I neurokinin-1 receptor-bearing neurons appear to be involved in intensity discriminative aspects of pain, whereas the deep neurokinin-1 cells are involved in spatial localization or the detection of particular nociceptive submodalities.
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PMID:Substance P receptor (neurokinin-1)-expressing neurons in lamina I of the spinal cord encode for the intensity of noxious stimulation: a c-Fos study in rat. 1005 Dec 14

The substance P receptor (SPR) is a G protein-coupled receptor (GPCR) that plays a key role in pain regulation. The SPR desensitizes in the continued presence of agonist, presumably via mechanisms that implicate G protein-coupled receptor kinases (GRKs) and beta-arrestins. The temporal relationship of these proposed biochemical events has never been established for any GPCR other than rhodopsin beyond the resolution provided by biochemical assays. We investigate the real-time activation and desensitization of the human SPR in live HEK293 cells using green fluorescent protein conjugates of protein kinase C, GRK2, and beta-arrestin 2. The translocation of protein kinase C betaII-green fluorescent protein to and from the plasma membrane in response to substance P indicates that the human SPR becomes activated within seconds of agonist exposure, and the response desensitizes within 30 s. This desensitization process coincides with a redistribution of GRK2 from the cytosol to the plasma membrane, followed by a robust redistribution of beta-arrestin 2 and a profound change in cell morphology that occurs after 1 min of SPR stimulation. These data establish a role for GRKs and beta-arrestins in homologous desensitization of the SPR and provide the first visual and temporal resolution of the sequence of events underlying homologous desensitization of a GPCR in living cells.
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PMID:Real-time visualization of the cellular redistribution of G protein-coupled receptor kinase 2 and beta-arrestin 2 during homologous desensitization of the substance P receptor. 1006 24

Substance P (SP) receptors in the ventral tegmental area (VTA) play a critical role in mediating the stress-induced activation of midbrain ascending dopamine (DA) neurons. Interestingly, SP acting in the VTA induces analgesia in the formalin test for tonic pain. Because exposure to stress inhibits pain in this test, we speculated that SP receptors in the VTA might mediate stress-induced analgesia. The present study explored this idea by examining the effect of blocking tachykinin NK-1 receptors in the VTA on footshock stress-induced analgesia in the formalin test. Intra-VTA infusions of the novel tachykinin NK-1 receptor antagonist, RP-67580, prevented this response. This finding suggests that exposure to stress inhibits tonic pain through the release of endogenous SP in the VTA.
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PMID:The tachykinin NK-1 receptor antagonist, RP-67580, infused into the ventral tegmental area prevents stress-induced analgesia in the formalin test. 1038 19

Hypertonic saline (HTS) induces bronchoconstriction. Potential mechanisms were evaluated in a human nasal provocation model. Aliquots of normal saline (1 x NS, 100 microliters) and higher concentrations (3 x NS, 6 x NS, 12 x NS, 24 x NS) were sprayed into one nostril at 5-min intervals. Lavage fluids were collected from the ipsilateral and contralateral sides to determine the concentrations of specific mucus constituents. Nasal cavity air-space volume was assessed by acoustic rhinometry (AcRh). The distribution of substance-P-preferring neurokinin-1 (NK-1) receptor mRNA was assessed by in situ reverse transcriptase-polymerase chain reaction. Unilateral HTS induced unilateral dose-dependent increases in sensations of pain, blockage, and rhinorrhea, the weights of recovered lavage fluids, and concentrations of total protein, lactoferrin, mucoglycoprotein markers, and substance P. Contralateral, reflex-mediated effects were minor. There were no changes in IgG or AcRh measurements. NK-1 receptor mRNA was localized to submucosal glands. HTS caused pain with unilateral substance P release. The presumed nociceptive nerve efferent axon response led to glandular exocytosis, presumably through actions on submucosal gland NK-1 receptors. Vascular processes, including plasma exudation, filling of venous sinusoids, and mucosal edema were not induced in these normal subjects.
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PMID:Hypertonic saline nasal provocation stimulates nociceptive nerves, substance P release, and glandular mucous exocytosis in normal humans. 1043 Jul 43


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