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)

To investigate substance P (SP) receptors on an established human astrocytoma cell line (U-87 MG), [3H][Sar9,Met(O2)11]-SP, a selective SP receptor agonist, was used to identify and characterize the cell membrane binding sites for SP. SP receptor mRNA was examined by solution hybridization analysis, and the existence of SP binding protein on the surface of membranes was evaluated by flow cytometry using an anti-SP binding protein antibody. In U-87 MG and U-373 MG RNA preparations, transcripts were identified that corresponded to both mature and partially spliced receptor forms. In U-87 MG cell membrane-enriched preparations, the binding of [3H][Sar9,Met(O2)11]-SP was found to be time and cell number dependent, specific, saturable, and of high affinity. Equilibrium binding analysis revealed a single class of binding sites with an apparent KD of 1.15 +/- 0.15 nM and a Bmax of 108 +/- 9.8 fmol/mg of protein. [3H][Sar9, Met(O2)11]-SP binding was basically not influenced by addition of mono (Na+, Li+) or divalent (Mg2+, Mn2+, Ca2+) cations; only high doses of divalent cations decreased the binding. GTP and guanylyl-5'-imidodiphosphate, but not GDP and GMP, reduced the Bmax without changing the affinity of [3H][Sar9,Met(O2)11]-SP. We also examined the effects of pretreatment with three lectins [concanavalin A (con A), wheat germ agglutinin (WGA), and Lens culinaris agglutinin (LCA)] to determine the nature of carbohydrate chains on the U-87 MG cell. Of three lectins analyzed for effects on agonist binding, WGA and LCA had an inhibitory effect, whereas con A was ineffective. These results suggest that SP receptors on the human astrocytoma cell line U-87 MG have either a biantennary complex-type or a high mannose-type of carbohydrate chain and may be regulated by GTP-binding protein(s).
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PMID:Human astrocytoma cells (U-87 MG) exhibit a specific substance P binding site with the characteristics of an NK-1 receptor. 886 85

Dorsal root ganglion neurons innervating skin via the saphenous nerve, muscle via the gastrocnemius nerve and viscera via the splanchnic nerve, were identified by retrograde tracing with Fast Blue applied to the cut nerve. Only neuronal profiles with nuclei were counted. At the survival times used no changes in immunohistochemical labelling patterns were detectable in the axotomized neurons. Percentages of Fast Blue-labelled neuronal profiles that were immunolabelled were calculated. The values for markers of carbohydrate groups were for skin, muscle and viscera, respectively: the lectin peanut agglutinin 55%, 24%, and 50%; the lectin soybean agglutinin 72%, 56%, 61%; the antibody 2C5 (against lactoseries groups) 43%, 20%, 6%; the antibodies SSEA-4 (against globoseries groups) 6%, 12%, 0% and SSEA-3 (against globoseries groups) 6%, 5%, 0%. The values for neurofilament rich profiles were for skin, muscle and viscera, respectively: 34%, 43%, 19%, and for carbonic anhydrase were 10%, 33%, 2%. Values for neuropeptides were, for calcitonin gene-related peptide 51%, 70%, 99%, for substance P 21%, 51%, 82%, and for somatostatin 10%, 2% and 0%. The population of skin afferents therefore contained the highest proportion of profiles expressing galactose containing carbohydrate groups labelled by 2C5 and the lectins and the highest proportion of cells with somatostatin. In contrast they had the lowest proportions of cells with calcitonin gene-related peptide and substance P, compared with the other tissues. Muscle afferents had the highest proportions compared with the other tissues of the neurofilament-rich, carbonic anhydrase-positive and SSEA-4-labelled profiles, but the lowest proportions of profiles with lectin binding. The splanchnic visceral afferents had the highest proportions, compared with the other tissues, of neuronal profiles labelled for calcitonin gene-related peptide and substance P, but the lowest proportions of neurofilament rich profiles and of profiles with carbonic anhydrase or 2C5 labelling and they totally lacked any labelling for globoseries carbohydrates and somatostatin. Both the muscle and skin afferent populations had clear small cell and large cell peaks in their size distributions, with the small cell peak being larger for skin than muscle afferents and the large cell peak being more marked for muscle afferents. The visceral afferent profiles had a unimodal size distribution with the peak size being between the small and large cell peaks of the somatic afferent units. This study therefore shows that the patterns of immunohistochemical labelling and cell size of primary afferent neurons differ according to their peripheral target tissue.
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PMID:Differences in expression of oligosaccharides, neuropeptides, carbonic anhydrase and neurofilament in rat primary afferent neurons retrogradely labelled via skin, muscle or visceral nerves. 960 20

Under the hypotheses of a structurally related binding site for antagonists of G-protein coupled receptors and the ability of cyclic pentapeptides of chiral sequence D1L2D3D4L5 to form rigid structures with which probe the pharmacophoric specificity of these receptors, inhibitors of substance P were designed based on available structure-activity relationships. ITF 1565, cyclo[D-Trp1-Pro2-D-Lys3-D-Trp4-Phe5], antagonized substance P activity mediated by type 1 neurokinin receptor (NK1) whereas it acted weakly against NK2 and did not inhibit endothelin at all. The preferential conformation of the peptide was obtained from nmr spectroscopy and computer calculations, and shown to contain the same beta II-turn and gamma'-turn found in other cyclic pentapeptides with the same chiral sequence. The structure of the peptide was compared with that of the beta-D-glucose molecule that has been proposed as a semirigid scaffold for antagonists of G-protein coupled receptors. The gamma'-turn of the cyclic peptide superimposed well with beta-D-glucose in the chair conformation. Furthermore, when the side chains were considered, the aromatic groups of the two molecules were found to generally overlap. These results support the view of G-protein coupled receptors as possessing structurally similar binding sites for antagonists and suggest that cyclic pentapeptides of chiral sequence D1L2D3D4L5 may be useful as semirigid scaffolds for the design of antagonists of this family of receptors.
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PMID:Cyclic pentapeptides of chiral sequence DLDDL as scaffold for antagonism of G-protein coupled receptors: synthesis, activity and conformational analysis by NMR and molecular dynamics of ITF 1565 a substance P inhibitor. 1038 Mar 45

A new sea urchin lectin from Toxopneustes pileolus, is D(+)galactose (Gal)-, D(+)fucose (Fuc)-specific. Incubation of rat peritoneal mast cells with the lectin in the presence of 0.3 mM CaCl2 for 10 min significantly and dose-dependently inhibited the histamine release induced by N-acetyl glucosamine (GlcNAc)-specific Datura stramonium agglutinin (DSA), an activator of the Gi-protein-dependent pathway in mast cells. This inhibition by the sea urchin lectin was sugar-specifically reversed in the presence of D(+)Gal or D(+)Fuc but not L(-)Fuc. The sea urchin lectin had no effect on the histamine release induced by compound 48/80, slightly inhibited the histamine release induced by substance P and mastoparan, and slightly enhanced the histamine release induced by melittin, but these effects were not dose-dependent. Compound 48/80, substance P, mastoparan and melittin are mast cell activators without sugar residues. It is suggested that the lectin binds to D(+)Gal residues of DSA to interfere with mast cell activation induced by DSA, a glycoprotein with arabinose and Gal residues. The effects of plant lectins with affinity to D(+)Gal, N-acetyl galactosamine and/or sialic acid and L(-)Fuc on the histamine release induced by DSA, compound 48/80 and substance P were also examined.
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PMID:D-galactose-specific sea urchin lectin sugar-specifically inhibited histamine release induced by datura stramonium agglutinin: differences between sugar-specific effects of sea urchin lectin and those of D-galactose- or L-fucose-specific plant lectins. 1138 49

In our continuing program exploring glucose-based peptidomimetics of somatostatin (SRIF-14), we sought to improve the water solubility of our glycosides. This led to insights into the nature of the ligand binding sites at the SRIF receptor. Replacement of the C4 benzyl substituent in glucoside (+)-2 with pyridinylmethyl or pyrazin-2-ylmethyl congeners increased water solubility and enhanced affinity for the human SRIF subtype receptor 4 (sst4). We attribute this effect to hydrogen bond formation. The pyridin-3-ylmethyl substituent at C4, when combined with the imidazol-4-ylmethyl group at C2, generated (-)-19, which has the highest affinity of a glucose-based peptidomimetic at a human SRIF receptor to date (K(i) 53 +/- 23 nM, n = 6 at sst4). The C4 heterocyclic congeners of glucosides bearing a 1-methoxy substituent rather than an indole side chain at the anomeric carbon, such as (+)-16, also provided information about the Trp(8) binding pocket. We correlated the SARs at both the C4 and the Trp(8) binding pockets with calculations of the electrostatic potentials of the diverse C4 aromatic substituents using Spartan 3-21G(*) MO analysis. These calculations provide an approximate analysis of a molecule's ability to interact within a receptor binding site. Our binding studies show that benzene and indole rings, but not pyridinylmethyl nor pyrazin-2-ylmethyl rings, can bind the hydrophobic Trp(8) binding pocket of sst4. The Spartan 3-21G(*) MO analysis reveals significant negative electrostatic potential in the region of the pi-clouds for the benzene and indole rings but not for the pyridinylmethyl or pyrazin-2-ylmethyl congeners. Our data further demonstrate that the replacement of benzene or indole side chains by heterocyclic aromatic rings typified by pyridine and pyrazine not only enhances water solubility and hydrogen bonding capacity as expected, but can also profoundly diminish the ability of the pi-cloud of the aromatic substituent to interact with side chains of an aromatic binding pocket such as that for Trp(8) of SRIF-14. Conversely, these calculations accommodate the experimental findings that pyrazin-2-ylmethyl and pyridinylmethyl substituents at C4- of C1-indole-substituted glycosides afford higher affinities at sst4 than the C4-benzyl group of (+)-2. This result is consistent with the high electron density in the plane of the heterocycle depicted in Figure 6 which can accept hydrogen bonds from the C4 binding pocket of the receptor. Unexpectedly, we found that the 2-fluoropyridin-5-ylmethyl analogue (+)-14 more closely resembles the binding affinity of (+)-8 than that of (+)-2, thus suggesting that (+)-14 represents a rare example of a carbon linked fluorine atom acting as a hydrogen bond acceptor. We attribute this result to the ability of the proton to bind the nitrogen and fluorine atoms simultaneously in a bifurcated arrangement. At the NK1 receptor of substance P (SP), the free hydroxyl at C4 optimizes affinity.
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PMID:Effects of heterocyclic aromatic substituents on binding affinities at two distinct sites of somatostatin receptors. Correlation with the electrostatic potential of the substituents. 1272 49

Recent evidence indicates that soybean, which is widely used in animal nutrition, could directly alter intestinal ion and nutrient transport. However, the mechanisms involved are still unknown. The aim of the study was to investigate the effect of three differently treated soybean products on the glucose and Cl- transport capacity in porcine small intestine by the Ussing chamber technique. Jejunal and ileal piglet epithelial tissues were pre-incubated with extracts of raw soybean flour (RSF), heated soybean flour (HSF), or ethanol heat-treated soybean protein concentrate (SPC). The Na(+)-dependent glucose co-absorption capacity was then measured as an increase in the short-circuit current (ISC) after luminal addition of D-glucose. The effect of the soybean products on cAMP-dependent Cl- secretion was measured as the increase in ISC after the addition of the phosphodiesterase inhibitor, theophylline, while nervous regulation of Cl- secretion was investigated by the addition of the enteric neurotransmitters; 5-hydroxytryptamine (5-HT), substance P and vasoactive intestinal polypeptide (VIP). Incubation with RSF and HSF induced a 30% decrease of the Na(+)-dependent glucose absorption capacity in the jejunum. The effect was similar for RSF in the ileum. Theophylline-induced secretion was decreased by 30% after incubation with RSF, HSF and SPC but only in the jejunum. 5-HT-, substance P- and VIP-induced secretion were not altered by incubation with soybean extracts except in the HSF-incubated where the substance P-induced secretion was significantly reduced. In conclusion, soybean contains ethanol-sensitive heat-insensitive compounds impairing Na(+)-dependent glucose absorption in the jejunum and ileum, and ethanol- and heat-insensitive compounds causing an acute impairment of cAMP-dependent jejunal secretion.
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PMID:Soybean impairs Na(+)-dependent glucose absorption and Cl- secretion in porcine small intestine. 1500 70

The distribution and modulation of the P2X(3) receptor was studied in trigeminal ganglion neurons to provide insight into the role of ATP in craniofacial sensory mechanisms. Binding to the d-galactose specific lectin IB4 was found in 73% of P2X(3)-positive neurons while only 16% of IB4 neurons expressed P2X(3). Neurons expressing P2X(3) alone were significantly larger than IB4-or IB4/P2X(3)-positive neurons. Investigation of target-specificity revealed that 22% of trigeminal ganglion muscle afferent neurons were positive for P2X(3) versus 16% of cutaneous afferent neurons. Muscle P2X(3) afferents were significantly smaller than the overall muscle afferent population while P2X(3) cutaneous afferent neurons were not. Presumptive heteromeric (P2X(2/3)) muscle afferent neurons were also identified and comprised 77% of the P2X(3) muscle afferent population. Muscle afferent neurons co-expressed P2X(3) with either calcitonin gene-related peptide (15%) or substance P (4%). The number of P2X(3)-positive muscle afferent neurons significantly increased one and four days following complete Freund's adjuvant-induced masseter muscle inflammation, but significantly decreased after 12 days. These results indicate that within trigeminal ganglia: (1) the P2X(3) receptor is expressed in both small and medium-sized neurons; (2) the P2X(3) receptor is not exclusively expressed in IB4 neurons; (3) P2X(3) is co-expressed with neuropeptides; (4) differences in the proportion of cutaneous versus muscle P2X(3) afferents are not apparent. Trigeminal P2X(3) neurons therefore differ markedly from dorsal root ganglion P2X(3) afferents. This study also shows that deep tissue inflammation modulates expression of the P2X(3) receptor and thus may warrant exploration as a target for therapeutic intervention.
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PMID:Trigeminal P2X3 receptor expression differs from dorsal root ganglion and is modulated by deep tissue inflammation. 1615 75

A novel 14-kDa lectin from Annona coriacea seeds (ACLEC) with hemagglutinating activity on erythrocytes has been recently described. Since plant lectins are known to present inflammatory activity, this study aimed to investigate the leukocyte migration induced by ACLEC, and inflammatory mediators involved in this phenomenon. Male Swiss mice were intraperitoneally injected with ACLEC (3-100 microg/cavity), and at 4-96 h thereafter the leukocyte counts in peritoneal lavage fluid were evaluated. ACLEC induced a dose-dependent neutrophil accumulation, reaching maximal responses at 16 h after injection (approximately 40-fold increase for 30 microg/cavity). Significant accumulation of mononuclear cells was observed at 72 h (2.7-fold increase). The carbohydrate mannose nearly abolished the neutrophil influx, whereas sucrose, glucose and galactose had no effect. Dexamethasone, the cyclooxygenase-2 (COX-2) inhibitor celecoxib and the Platelet activating factor (PAF) receptor antagonist PCA4248 significantly reduced ACLEC-induced neutrophil influx. The tachykinin NK(1) antagonist SR140333, the tachykinin NK(2) antagonist SR48968, the non-selective NO inhibitor L-NAME, the selective inducible NOS inhibitor aminoguanidine and the lypoxygenase inhibitor AA861 all failed to modify the ACLEC-induced responses. In conclusion, ACLEC is able to attract neutrophils into the mice peritoneal cavity by mechanisms involving interactions of the lectin with cell-specific mannose recognition, leading to the release of COX-2-derived mediators and PAF.
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PMID:Neutrophil migration in mice induced by a mannose-binding lectin isolated from Annona coriacea seeds. 1692 40

The isolectin B4 (IB4) stains a subset of small and medium-sized dorsal root ganglion (DRG) neurons by binding to terminal alpha-galactose on glycoproteins and glycolipids. The enzymes alpha(1,3)galactosyltransferase (1,3GT) and isoglobotriaosylceramide synthase (iGb3S) synthesize the galactose-alpha(1,3)-galactose group, which is the most common carbohydrate containing terminal alpha-galactose. 1,3GT preferentially glycosylates proteins whereas iGb3S glycosylates lipids. We generated antibodies against rat 1,3GT and iGb3S that were used for immunohistochemical staining of DRG cells. Virtually all neurons that bound IB4 expressed both enzymes, suggesting that IB4 binds to both glycoproteins and glycolipids in IB4-positive neurons. 1,3GT immunoreactivity was observed in small and medium-sized neurons and satellite cells. iGb3S immunoreactivity was observed in neurons of varying sizes. Many neurons that expressed these enzymes did not bind IB4. Additionally, the majority of neurons that expressed substance P expressed both enzymes but did not bind IB4. Ultrastructual studies revealed that 1,3GT was predominantly associated with the Golgi apparatus, whereas iGb3S was found near the Golgi apparatus and in large, clear vesicles throughout the soma. These data suggest that, although expression of 1,3GT and/or iGb3S appears to be necessary for IB4 binding, expression of these enzymes is not sufficient to impart IB4 binding.
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PMID:Enzymes that synthesize the IB4 epitope are not sufficient to impart IB4 binding in dorsal root ganglia of rat. 1720 13

The diagnosis and treatment of irritable bowel syndrome (IBS) are complicated. Artichoke extracts are well known to be helpful in various gastrointestinal disorders. A hydrophilic extract 36_U mainly containing luteolin-7-glycoside, luteolin-7-O-glucoside, small amounts of cynarin and luteolin increased contraction of rat ileum. This is mainly mediated by 5-HT(3) - and 5-HT(2) receptors but not 5-HT(4) receptors as can be derived by using specific antagonists such as tropisetrone, GR113806 and ketanserine. Additional mechanisms (receptors) are involved since the combination of these three antagonists was not able to fully prevent the contractive effect of extract 36_U. The lipophilic extract 36_EB mainly containing cynarin, luteolin including its glycosides, and cholorogenic acid in contrast to extract 36_U had a relaxing effect which could hardly be washed out. It was diminishing a serotonin effect and was not modified by ACh or substance P. The peristaltic threshold, i.e. the distension necessary for inducing a pathophysiologically relevant propulsion activity, is one of the important features being correlated with IBS. The peristaltic threshold was decreased by both serotonin and extract U_36. From the data it can be derived that the extract 36_U may be useful in IBS combined with obstipation when gastrointestinal contraction is necessary, whereas 36_EB may be useful in IBS combined with diarrhea when gastrointestinal relaxation is desired. Especially interesting are the influence on the threshold. It would be interesting to know which effects are mediated via cynarin and luteolin or its glycosides.
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PMID:Effect of two artichoke extracts (36_U and 36_EB) on rat ileum (with respect to bowel syndrome) and the peristaltic threshold. 1842 4


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