Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P20366 (substance P)
 21,176 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The i.v. administration of substance P (SP, 0.25-16 micrograms/kg) or of the selective metabolic stable NK-1 agonist, [Glp6,Pro9]SP-(6-11) (septide, 0.03-0.25 microgram) to atropine-treated guinea pigs or to isolated perfused lungs triggered a dose-dependent bronchoconstriction, which was enhanced in animals actively sensitized to ovalbumin. In vivo, bronchial hyper-responsiveness was restricted to SP and to septide, inasmuch as neurokinin A (0.06-1 microgram/kg)- or capsaicin (0.5-32 micrograms/kg)-induced bronchoconstriction were not modified. In contrast, isolated lungs from sensitized guinea pigs exhibited an increased bronchoconstriction also in response to capsaicin (0.01-10 micrograms), which was inhibited by atropine in the medium. Pretreatment of actively sensitized guinea pigs either with indomethacin plus mepyramine, the lipoxygenase inhibitor BW A4C or with the platelet-activating factor antagonist SR 27417, did not modify bronchial hyper-reactivity to SP. Captopril (5 mg/kg i.v.), but not thiorphan (0.8 mg/kg i.v.), increased the SP-induced bronchoconstriction in actively sensitized animals, whereas both inhibitors were equally effective in nonsensitized guinea pigs. Thiorphan, however, did not modify the in vivo response to septide. Our results demonstrate that guinea pigs sensitized to ovalbumin exhibit bronchial hyperreactivity to SP, but not to neurokinin A, as compared to nonsensitized animals, suggesting a decrease in the neutral endopeptidase activity in the airways brought by the immunization. However, the results obtained by using septide indicate that other mechanisms may be involved in the bronchial hyper-reactivity to SP.
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PMID:Effect of active sensitization on the bronchopulmonary responses to tachykinins in the guinea pig. Modulation by peptidase inhibitors. 835 11

The ability of peptidases to restrict neurokinin 1 receptor (NK1R) activation by exogenously applied or endogenously released neurokinins was investigated by measuring NK1R internalization in rat spinal cord slices. Concentration-response curves for substance P and neurokinin A were obtained in the presence and absence of 10 microm thiorphan, an inhibitor of neutral endopeptidase (EC 3.4.24.11), plus 10 microm captopril, an inhibitor of dipeptidyl carboxypeptidase (EC 3.4.15.1). These inhibitors significantly decreased the EC50 of substance P to produce NK1R internalization from 32 to 9 nm, and the EC50 of neurokinin A from 170 to 60 nm. Substance P was significantly more potent than neurokinin A, both with and without these peptidase inhibitors. In the presence of peptidase inhibitors, neurokinin B was 10 times less potent than neurokinin A and 64 times less potent than substance P (EC50=573 nm). Several aminopeptidase inhibitors (actinonin, amastatin, bacitracin, bestatin and puromycin) failed to further increase the effect of thiorphan plus captopril on the NK1R internalization produced by 10 nm substance P. Electrical stimulation of the dorsal root produced NK1R internalization by releasing endogenous neurokinins. Thiorphan plus captopril increased NK1R internalization produced by 1 Hz stimulation, but not by 30 Hz stimulation. Therefore, NEN and DCP restrict NK1R activation by endogenous neurokinins when they are gradually released by low-frequency firing of primary afferents, but become saturated or inhibited when primary afferents fire at a high frequency.
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PMID:Effect of peptidases on the ability of exogenous and endogenous neurokinins to produce neurokinin 1 receptor internalization in the rat spinal cord. 1462 71

Excitotoxic damage appears to be a critical factor in the formation of perinatal brain lesions associated with cerebral palsy (CP). When injected into newborn mice, the glutamatergic analogue, ibotenate, produces cortical lesions and white matter cysts that mimic human perinatal brain lesions. Neuropeptides are neuronal activity modulators and could therefore modulate glutamate-induced lesions. However, neuropeptides are rapidly degraded by peptidases. Racecadotril, which is rapidly metabolized to its active metabolite thiorphan, is a neutral endopeptidase (NEP) inhibitor used in clinical practice for diarrhoea with a remarkable safety profile. This study aimed to test the original hypothesis that thiorphan could be neuroprotective against ibotenate-induced lesions in newborn mice. Intraperitoneal administration of thiorphan reduced ibotenate-induced cortical lesions by up to 57% and cortical caspase-3 cleavage by up to 59%. This neuroprotective effect was long-lasting and was still observed when thiorphan was administered 12 h after the insult, showing a remarkable window for therapeutic intervention. Further supporting the neuroprotective effect of pharmacological blockade of NEP, mouse pups with a genetic deletion of NEP displayed a significantly reduced size of the ibotenate-induced cortical grey matter lesion when compared with wild-type animals. Thiorphan effects were mimicked by substance P (SP) and, in a less potent manner, by neurokinin A. Thiorphan effects were inhibited by blockers of NK1 and NK2 receptors. Real-time reverse transcription-polymerase chain reaction, autoradiography and immunohistochemistry confirmed the expression of NK1 and NK2 receptors in the neonatal murine neocortex. These data demonstrate that thiorphan prevents neonatal excitotoxic cortical damage, an effect largely mediated by SP. Thiorphan could represent a promising drug for the prevention of CP, which remains a challenging disease. In a broader context, these results also raise potential implications for the prevention of neurodegenerative diseases involving glutamate-mediated excitotoxic neuronal death.
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PMID:Thiorphan, a neutral endopeptidase inhibitor used for diarrhoea, is neuroprotective in newborn mice. 1702 11

The activity of substance P (SP) in the rat thymus seems to be tightly controlled by its bioavailability. In this study, we provide evidence for the expression of the SP-degrading enzyme, neutral endopeptidase (NEP)/CD10, by rat thymocyte subsets, and we illustrate its involvement in the in vivo SP/neurokinin-1 receptor (NK(1)R)-mediated regulation of thymocyte survival and proliferation. NEP/CD10 was expressed at both mRNA and protein levels on a substantial portion (45.5%) of CD5(+) thymocytes, namely on the CD4(+)CD8(+) (double positive; DP) and CD4(+) subsets. Continuous administration of thiorphan, a specific NEP/CD10 inhibitor, by means of miniosmotic pumps, enhanced rat thymocyte preprotachykinin-A (PPT-A) and NK(1)R mRNA expression as well as SP and NK(1)R protein levels in an NK(1)R-dependent manner. Thiorphan increased CD10(+)CD4(+) and CD10(+)DP thymocyte numbers, and an NK(1)R antagonist, (S)1-{2-[3(3-4-dichlorophenyl)-1-(3-iso-propoxyphenylacetyl)-piperidine-3-yl]ethyl}-4-pheny-1-azoniabicyclo[2.2.2]octane, chloride (SR140333), abrogated these stimulatory effects. In addition, the NEP/CD10 inhibitor stimulated interleukin (IL)-2 production, IL-2 receptor alpha chain expression, and concanavalin A-induced proliferation of CD5(+) thymocytes, and it inhibited spontaneous and NK(1)R-dependent thymocyte apoptosis. The thiorphan-protective antiapoptotic and proliferative effects involved the activation of Akt serine-threonine kinase, subsequent up-regulation of survivin mRNA, down-regulation of procaspase-3 mRNA levels, and suppression of caspase-3 activity, which were inhibited by SR140333 and mimicked by exogenous SP administration. Overall, our findings suggest that by controlling SP availability, NEP/CD10 negatively regulates thymocyte homeostasis and development.
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PMID:Thiorphan-induced survival and proliferation of rat thymocytes by activation of Akt/survivin pathway and inhibition of caspase-3 activity. 1862 88


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