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

Irritable bowel syndrome (IBS) is one of several functional gastrointestinal disorders commonly encountered in both the clinical setting and the general population. The biopsychosocial model is currently believed to be a more complete explanatory mechanism of IBS symptom genesis and propagation. Gut inflammation and immune activation is one of the biological mechanisms for which evidence is emerging. Experimental parasitic infection of mice bowel resulted in elevated substance P levels and increased expression of cyclooxygenase 2 (COX 2) enzyme, prostaglandin E2, IL-4, IL-5, and IL-13. In IBS patients, increased cellularity and proximity of the inflammatory or immune cells to the nerve trunks of the bowel, elevated interleukin-1beta mRNA expression in mucosal biopsies, and increased inducible nitric oxide synthase and nitrotyrosine elaboration (indicative of lymphocyte activation) were observed. Corticosteroids given after the elimination of an experimentally applied parasite from the bowel of mice resulted in the reversal of persistent gut muscle dysfunction. Selective COX-2 inhibitors attenuated the increased bowel smooth muscle contractility resulting from parasite infection of mice gut. In humans, it has been observed that the relative risk of developing IBS in asthma patients was reduced by 60% by the use of oral steroids. Despite such preclinical and human evidence for the role of inflammation and immune activation in IBS, the efficacy of anti-inflammatory and immunomodulatory agents has not been adequately investigated. Budesonide, a corticosteroid with a high mucosal activity and a low bioavailability, is an anti-inflammatory agent that may be worth investigating for its utility in diarrhea-predominant IBS.
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PMID:Will corticosteroids and other anti-inflammatory agents be effective for diarrhea-predominant irritable bowel syndrome? 1589 25

The symptomatic management of irritable bowel syndrome (IBS) and functional dyspepsia, which often overlap, can be frustrating and difficult. Education and reassurance remain central for management although controlled trials are lacking. Psychological interventions may be useful in select patients but methodological inadequacies in clinical trials limit their interpretability. For symptom exacerbations, drug treatment is reasonable but no current treatment successfully targets the full symptom complex. Bulking agents are not of proven efficacy in IBS; they may improve constipation but worsen bloating and pain. Anticholinergics are of uncertain value in IBS. A meta-analysis of trials of smooth muscle relaxants for IBS has been reported to be positive but the quality of the trials included was poor. Antidepressants for IBS and functional dyspepsia appear to be efficacious based on the limited published evidence; both global symptoms and abdominal pain improve. Selective serotonin reuptake inhibitors (SSRIs) are of uncertain efficacy but anecdotally appear to be useful. Laxatives are not of proven efficacy in IBS. Loperamide improves diarrhea, but not abdominal pain in IBS. No drug is of proven efficacy for bloating. Acid suppression remains the mainstay of therapy for functional dyspepsia but the majority of patients do not have an adequate response. Promising drugs include new prokinetics for constipation-predominant IBS (e.g., tegaserod, a partial 5-HT4 agonist, prucalopride, a full 5-HT4 agonist, and dexloxiglumide, a cholecystokinin1 antagonist), agents for diarrhea-predominant IBS (e.g., 5-HT3 antagonists, alpha2 receptor agonists and corticotrophin receptor-1 antagonists), other visceral analgesics (e.g. tachykinin antagonists, opioid agonists) and in dyspepsia fundus relaxing agents (e.g., 5-HT1 agonists, tegaserod).
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PMID:New and emerging treatments for irritable bowel syndrome and functional dyspepsia. 1598 38

Acute diarrhea is a major cause of morbidity and mortality worldwide. Infants and pre-school children are the most vulnerable in whom there are 2-3 million deaths each year as a result of the associated dehydration and acidosis. Although oral rehydration therapy has reduced mortality during the past 30 years ago, the search for agents that will directly inhibit intestinal secretory mechanisms and thereby reduce faecal losses in patients with high-volume watery diarrhea has continued for more than 20 years. A variety of potential targets for antisecretory agents have been explored which include loci within the enterocyte (the chloride channel, calcium-calmodulin) and other sites such as enteric nerves and endogenous mediators (such as 5-HT, prostaglandins). Although the potential of calcium-calmodulin inhibition has as yet not been realised, preliminary studies suggest that there are chloride channel blockers under development that will find a place in the management of secretory diarrheas. Recent work has highlighted the importance of neurohumoral mechanisms in the pathogenesis of acute diarrhea. Potentiation of the effects of endogenous enkephalin activity by enkephalinase inhibition has already produced a safe, effective anti-secretory drug, racecadotril. Speculative early work indicates that there may be a role for antagonists of 5-HT, substance P, and VIP receptors. There now seems to be a real possibility that antisecretory therapy will become more widely available in the future.
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PMID:Antisecretory drugs for diarrheal disease. 1669 63

Dietary zinc treatment has a preventive impact on diarrhoea in newly weaned piglets and in undernourished children. The mechanisms behind this effect of zinc are however, still not fully understood. The aim of the present study was to assess if zinc has a direct effect on porcine intestinal secretory responses to different secretagogues in vitro. The study included two Ussing chamber experiments, where the short circuit current responses to different secretagogues were measured in piglet small intestinal epithelium. Exp. 1 aimed to study the effect of increased zinc concentrations in the bathing media on the secretory responses to 5-HT and theophylline. The objective of exp. 2 was to study the effect of zinc in the bathing media on the secretory responses induced by vasoactive intestinal polypeptide (VIP), Substance P (SP), Carbachol, and theophylline. The results showed that there were significant decreasing effects of zinc on the secretion, stimulated by 5-HT, VIP and carbachol, from piglet intestinal epithelium in vitro, whereas the secretion caused by SP and theophylline was not significantly affected. The data indicate that the inhibitory mechanism of zinc ions may take place at the receptors situated at the basolateral membrane of the epithelial cells.
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PMID:Zinc reduces the electrophysiological responses in vitro to basolateral receptor mediated secretagogues in piglet small intestinal epithelium. 1675 98

The possibility of links between psychosocial factors and cancer incidence and progression has generated considerable scientific and public interest. Tachykinins, including substance P, neurokinin A and B, hemokinin-1 and endokinins, are a family of neuropeptides, acting through three types of transmembrane G-protein coupled receptors denoted NK1, NK2 and NK3. Besides their role as neurotransmitters in peripheral and central nervous system, tachykinins and their receptors are also expressed in several non neuronal cells contributing to the fine connections between nervous systems and peripheral organ system such as respiratory, cardiovascular, immune, endocrine, gastrointestinal and genitourinary. Being so much involved in regulating physiological functions, they, of course, can concur to pathological conditions including cancer. Tachykinins can act on different steps of carcinogenesis. Tumors expressing NK receptors, such as astrocytoma, glioma, neuroblastoma, pancreatic cancer and melanoma, can misuse tachykinin-induced signaling, operating in normal cells, to promote proliferation and survival of cancer cells and to release cytokines and soluble mediators favoring tumor growth. In neuroblastoma, breast and prostate carcinomas tachykinins facilitate tumor metastatic infiltration in the bone marrow. In neuroendocrine carcinoma, tachykinins are responsible of symptoms associated with these pathologies including flushing, diarrhea, wheezing and right heart disease. In addition, regardless tumor histology, tachykinins may favor cancer incidence and metastatic progression by influencing blood flux and neovascularization in tumor formation as well as inducing immunosuppression mediated by neurogenic inflammation due to stress or surgery. However, the precise involvement of tachykinins in cancer pathologies and the potentiality to become effective pharmacological drug targets remain to be fully defined.
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PMID:Tachykinins and their receptors in human malignancies. 1691 32

The gastro-intestinal tract is highly innervated by both intrinsic and extrinsic sensory nerves and this neuronal component is thought to play a role in local inflammatory responses. This in vivo study was designed to determine the function of substance P and the tachykinin NK1 receptor in the pathogenesis of inflammatory bowel disease by the use of the specific antagonist RP 67580. The dinitrofluorobenzene (DNFB)-induced colonic hypersensitivity model is associated with increased levels of substance P in the colon. The tachykinin NK1 receptor antagonist RP 67580 was used to investigate the role of substance P on the development of diarrhea, mast cell infiltration and activation, colonic tissue damage, hypertrophy of colonic lymphoid structures and leukocyte infiltration. The formation of watery diarrhea could completely be abrogated by treatment with RP 67580 in DNFB-sensitized animals 72 h after challenge. Antagonizing the tachykinin NK1 receptor in these animals also resulted in significantly reduced colonic patch hypertrophy, leukocyte recruitment and tissue damage. Total levels of substance P in the colon of DNFB-sensitized mice treated with the inactive enantiomer of the tachykinin NK1 receptor antagonist were significantly higher compared to DNFB-sensitized mice treated with RP 67580 72 h after challenge. Although RP 67580 was capable of reducing the total number of mast cells present in the colon, mast cell activation was not affected by this treatment. In conclusion, in this chemically-induced immunological model for inflammatory bowel disease we demonstrated an important role for tachykinin NK1 receptors, and its ligand substance P, in the development of colitis downstream from mast cell activation.
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PMID:Beneficial effect of tachykinin NK1 receptor antagonism in the development of hapten-induced colitis in mice. 1694 72

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

Cryptosporidiosis, caused by the protozoan parasite Cryptosporidium, causes self-limited diarrhea in immunocompetent hosts and severe life-threatening diarrhea in AIDS patients. Highly active antiretroviral therapy has been used to effectively treat cryptosporiosis in some but not all AIDS patients. Therefore, there is an urgent need for innovative drugs to treat this disease. Cryptosporidium infection results in intestinal pathophysiological changes such as glucose malabsorption, increased chloride ion (Cl(-)) secretion, and epithelial barrier disruption, leading to disease pathogenesis. In order to develop tools to combat this opportunistic pathogen, it is vital to understand mediators involved in disease pathogenesis. Substance P (SP), a neuropeptide and pain transmitter, is located in the gastrointestinal tract. SP can cause Cl(-) secretion in human gastrointestinal explants. However, its role in cryptosporidiosis has not been fully studied. Jejunal samples from macaques before and after Cryptosporidium parvum infection were assayed for SP and SP receptor mRNA and protein levels by reverse transcription-PCR and by immunohistochemistry and enzyme-linked immunosorbent assay, respectively. The role of SP in pathophysiological alterations, such as Cl(-) secretion and glucose malabsorption, was studied using tissues derived from macaques infected with C. parvum by the Ussing chamber technique. SP and SP receptor mRNA and protein expression levels were increased in jejunal samples following C. parvum infection and were accompanied by increased basal ion secretion and glucose malabsorption. In vitro treatment of samples obtained from infected macaques with the SP receptor antagonist aprepitant (Emend; Merck, Whitehouse Station, NJ) completely reversed the increase in basal ion secretion and corrected the glucose malabsorption. Our findings raise the possibility of using SP receptor antagonists for the treatment of symptoms associated with cryptosporidiosis.
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PMID:Substance P is responsible for physiological alterations such as increased chloride ion secretion and glucose malabsorption in cryptosporidiosis. 1715 91

Communication between nerves and immune and inflammatory cells of the small and large intestine plays a major role in the modulation of several intestinal functions, including intestinal motility, ion transport, and mucosal permeability. Neuroimmune interactions at intestinal sites have been associated with the pathophysiology of infectious and enterotoxin-mediated diarrhea and intestinal inflammation, including inflammatory bowel disease (IBD). During the past 20 years the neuropeptide substance P (SP) has been identified as an important mediator in the development and progress of intestinal inflammation by binding to its high-affinity neurokinin-1 receptor (NK-1R). This peptide, released from enteric nerves, sensory neurons, and inflammatory cells of the lamina propria during intestinal inflammation, participates in gut inflammation by interacting, directly or indirectly, with NK-1R expressed on nerves, epithelial cells, and immune and inflammatory cells, such as mast cells, macrophages, and T cells. SP-dependent activation of these cells leads to the release of cytokines and chemokines as well as other neuropeptides that modulate diarrhea, inflammation, and motility associated with the pathophysiology of several intestinal disease states. The recent development of specific nonpeptide NK-1R antagonists and NK-1R-deficient mice helped us understand the functional importance of the SP-NK-1R system in mediating intestinal neuroimmune interactions and to identify the particular cells and signaling pathways involved in this response. This review summarizes our understanding on the immunomodulatory properties of SP and its receptor in the intestinal tract with particular focus on their involvement in intestinal physiology as well as in the pathophysiology of several intestinal disease states at the in vivo and cell signaling level.
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PMID:Immunomodulatory properties of substance P: the gastrointestinal system as a model. 1719 54

The 5-HT3 receptor is a pentameric ligand-gated cation channel which is found in the central and peripheral nervous system and on extraneuronal locations like lymphocytes, monocytes and fetal tissue. Five monomer subtypes, the 5-HT(3A-E) subunits, have been identified which show differences in the amino-terminal and the transmembrane region. The functional relevance of different receptor compositions is not yet clarified. 5-HT3 receptors are located predominantly in CNS regions that are involved in the integration of the vomiting reflex, pain processing, the reward system and anxiety control. The preferential localization on nerve endings is consistent with a physiological role of 5-HT3 receptors in the control of neurotransmitter release such as dopamine, cholecystokinin, glutamate, acetylcholine, GABA, substance P, or serotonin itself. 5-HT3-receptor agonists cause unpleasant effects like nausea and anxiety, and no clinical use has been considered. In contrast, the introduction of 5-HT3-receptor antagonists for chemotherapy-induced vomiting was extremely successful. After development of other gastrointestinal indications like postoperative vomiting and diarrhea-predominant irritable bowel syndrome recent research focuses on rheumatological indications such as fibromyalgia, rheumatoid arthritis and tendinopathies. Positive effects have also been observed for pain syndromes such as chronic neuropathic pain and migraine. These effects seem to be related to substance P-mediated inflammation and hyperalgesia. Furthermore, antiinflammatory and immunomodulatory properties have been observed for 5-HT3-receptor antagonists which might explain promising findings in systemic sclerosis and other immunological conditions. For all of these innovative indications the optimal dosing schedule is a crucial issue, since a bell-shaped dose-response curve has been observed repeatedly for 5-HT3-receptor antagonists, particularly in CNS effects.
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PMID:The neuronal 5-HT3 receptor network after 20 years of research--evolving concepts in management of pain and inflammation. 1731 6


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