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)

Substance P (SP) binding protein of rat brain was solubilized by digitonin. The solubilized proteins were then purified by sequential gel filtration, concanavalin A lectin Sepharose, and SP-affinity chromatography. The calculated molecular weight of this purified SP binding protein was 76-74 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The rabbits were immunized with the purified protein and resulting polyclonal anti-sera were tested. The immune serum significantly inhibited [3H]SP binding to the 3-[(3-cholamidopropyl)dimethylammonio]-1-propane sulfonate solubilized membrane fractions from rat brain, whereas pre-bleed antiserum failed to inhibit the binding. This polyclonal antibody also inhibited the activity of 45Ca influx into astroglioma cells stimulated by SP, but does not inhibit that stimulated by histamine. Furthermore, this polyclonal antibody recognized the 76-74 kDa band as assessed by Western blotting. These data strongly suggest that this polyclonal antibody could recognize a part of the natural SP receptor site.
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PMID:Isolation of substance P binding protein from rat brain. 127 54

The neurokinin-1 (NK-1, substance P) receptor belongs to the class of seven transmembrane domain (7-TM) receptors that interact with cellular effector systems via guanine nucleotide binding regulatory proteins (G-proteins). In this study, coupling mechanisms of functional NK-1 receptors endogenously expressed in a human astrocytoma cell line (U373MG) were analyzed. Stimulation with substance P (SP) resulted in 1) a rapid increase in inositol 1,4,5-trisphosphate (IP3) synthesis; 2) a rise in cytosolic free calcium concentration ([Ca2+]i); 3) induction of immediate early gene transcription as monitored by c-fos and c-jun expression; and 4) a significant increase in de novo DNA synthesis. Thus, the functional responses induced by stimulation of NK-1 receptors on U373MG strongly correlate with those observed after treatment of primary astrocytes with SP and make U373MG cells a useful in vitro model system for the analysis of NK-1 receptor function on astrocytes in vivo.
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PMID:Functional characterization of neurokinin-1 receptors on human U373MG astrocytoma cells. 132 53

UC11 cells, derived from a human astrocytoma, have a high density of functional substance P receptors. Radioligand binding studies were conducted with the highly selective neurokinin-1 receptor ligand [3H][Sar9,Met(O2)11]-substance P. Kinetic binding experiments conducted at 4 degrees C yielded an association rate constant k1 of 1.86 x 10(7) M-1 min-1, a dissociation rate constant k-1 of 0.00478 min-1, and a calculated kinetic KD of 257 pM. Saturation binding experiments yielded average values of KD = 447 +/- 103 pM, Bmax = 862 +/- 93 fmol/mg of protein. This Bmax corresponds to more than 150,000 binding sites/cell. Competition binding experiments with unlabeled [Sar9,Met(O2)11]-substance P yielded average values of KD = 491 +/- 48 pM and Bmax = 912 +/- 67 fmol/mg of protein. In [3H]inositol-labeled cells, substance P induced a robust inositol phosphate formation. Inositol trisphosphate levels increased as much as 20-fold within approximately 15 s of addition of substance P. This inositol trisphosphate formation was transient and had returned to baseline within the first 60-120 s. Inositol monophosphate formation, however, was linear for at least 2 h. Structure activity data on binding and inositol monophosphate formation confirmed the presence of a neurokinin-1 receptor subtype in these cells. Thus, the UC11 cell should be a useful model cell for delineating the physiological role of substance P receptors in astrocytes.
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PMID:Characterization of receptors for substance P in human astrocytoma cells: radioligand binding and inositol phosphate formation. 137 Mar 19

125I-Bolton-Hunter-substance P (125I-BH-SP) binding properties of three novel classes of neurokinin-1 (NK-1) receptor antagonists were investigated in tissues derived from humans, guinea pigs, and rats. 125I-BH-SP was shown to bind to a single class of binding sites, with similar dissociation constants, Kd, in human astrocytoma cells (U-373 MG), human urinary bladder, guinea pig forebrain, guinea pig ileum longitudinal smooth muscle, rat forebrain, and rat duodenum. In each tissue preparation, known peptide agonists and peptide antagonists yielded potencies typical for a NK-1 receptor profile, with little difference in binding properties between the various tissues. However, when the three classes of compounds, heterosteroids, cyanines, and modified peptides, were tested for their ability to displace 125I-BH-SP binding from the NK-1 receptor, very different binding profiles were observed. The heterosteroids were shown to be as much as 3 orders of magnitude more potent in tissues derived from rats than from humans or guinea pigs. A distinct species-dependent structure-activity relationship (SAR) was also observed for this class of compounds. Like the heterosteroids, the cyanines displaced 125I-BH-SP with 10-30-fold higher affinity in rat tissues than in human and guinea pig tissues. However, the SAR generated by the cyanines was comparable in all tissues studied. The modified peptides, on the other hand, were up to 10-100-fold more potent in human and guinea pig than rat tissues, producing a SAR that differed between the various species. No differences in binding properties between central nervous system and peripheral tissues from the same species were seen with these compounds. These results provide evidence for species differences in NK-1 receptors in humans, guinea pigs, and rats. Because it is known that there exists great sequence identity between rat and human NK-1 receptors, it is hypothesized that key amino acid changes or different lipid environments within the transmembrane binding region of the receptor may account for the observed species difference. Furthermore, this study emphasizes that caution is necessary in the choice of species to be used in development programs targeted towards therapeutic entities in the NK-1 receptor antagonist area.
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PMID:Antagonists that demonstrate species differences in neurokinin-1 receptors. 137 2

The activation of NK1 receptors on U373 MG human astrocytoma cells by substance P (SP) and related tachykinins was accompanied by an increase in taurine release and an accumulation of inositol phosphates. Both of these effects could be inhibited by spantide, a SP receptor antagonist. The relative potency of tachykinins in stimulating 3H-inositol phosphate accumulation correlated very well with their effects in stimulating the release of [3H]-taurine and inhibition 125I-Bolton-Hunter reagent-conjugated SP binding. The effect on [3H]taurine release was mimicked by a protein kinase C (PKC) activator, phorbol 12-myristate 13-acetate (PMA). The inactive phorbol ester analogue 4-alpha-phorbol 12,13-didecanoate, however, was without effect. Both SP- and PMA-induced releases of [3H]-taurine were markedly inhibited by staurosporine, a potent PKC inhibitor. Pretreatment of U373 MG cells with 10 microM PMA for 19 h to down-regulate PKC activity also markedly inhibited both SP- and PMA-induced releases of [3H]-taurine. Treatment of cells with 100 nM SP induced a time-dependent translocation of PKC from the cytosolic fraction to the membrane fraction. These findings are consistent with the hypothesis that an activation of NK1 receptors on U373 MG cells results in the release of inositol phosphates and activation of PKC, which in turn may regulate the release of taurine.
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PMID:Tachykinin-stimulated inositol phospholipid hydrolysis and taurine release from human astrocytoma cells. 137 85

Substance P (SP) stimulated [3H]taurine release from human astrocytoma cells (U-373 MG). This effect was concentration dependent and the EC50 was 0.3 nM. This stimulatory effect of SP can be inhibited by spantide, a SP receptor antagonist. The rank order of potencies of related tachykinins and their analogues in stimulating the release of [3H]taurine was SP much greater than neurokinin A much greater than neurokinin B and [Glp6,L-Pro9]SP (6-11) much greater than [Glp6, D-Pro9]SP (6-11) which conformed to that reported for the tachykinin NK-1 receptor. In addition to SP, isoproterenol, a beta-adrenergic agonist, can also increase the release of [3H]taurine from these cells and the effects of SP and isoproterenol were additive.
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PMID:Effects of tachykinins on [3H]taurine release from human astrocytoma cells (U-373 MG). 171 6

A cDNA encoding the human substance P receptor (SPR) was isolated and the primary structure of the protein was deduced by nucleotide sequence analysis. This SPR consists of 407 residues and is a member of the G-protein coupled receptor superfamily. Comparison of rat and human SPR sequences demonstrated a 94.5% identity. The receptor was expressed in a COS-7 cell line and displayed a Kd for Tyr-1-SP binding of 0.24 nM. Ligand displacement by naturally occurring tachykinin peptides was SP much greater than neurokinin A greater than neurokinin B. SP stimulation of transfected cells resulted in a rapid and transient inositol 1,4,5-trisphosphate response. RNA blot hybridization and solution hybridization demonstrated that SPR mRNA was about 4.5 Kb in size, and was expressed in IM-9 lymphoblast and U373-MG astrocytoma cells, as well as in spinal cord and lung but not in liver.
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PMID:Molecular cloning, structural characterization and functional expression of the human substance P receptor. 171 67

This study examined the influence of cytokines on substance P (SP) receptors (NK1 subtype) in the human astrocytoma cell line UC11. Following trypsinization and passage, the density of SP receptors in these cells was rather low but gradually increased several fold over the course of a few days in culture. Frequent replacement of the growth medium enhanced the density of receptors even more, suggesting that growth factors in the culture medium may determine the levels of receptor. Exposure of the cells to sub-nanomolar concentrations of tumor necrosis factor (TNF alpha) or interleukin-1 beta (IL1 beta), but not interleukin-2 or interleukin-6, decreased the density of SP receptors. This was accompanied by a decrease in the ability of SP to stimulate inositolphosphate formation. The ability of histamine to activate inositolphosphate formation was not influenced by the cytokines. The decrease in SP receptor density was readily reversible on washout of the cytokines. The EC50 for TNF alpha was approximately 0.5 ng/ml, the EC50 for IL1 beta was approximately 0.1 ng/ml. Radioligand binding studies with [125I]TNF alpha indicated the presence of a low density of high affinity binding sites for this ligand: Kd = 2.5 +/- 0.6 ng/ml, Bmax = 14.8 +/- 2.7 fmol bound/mg protein (assuming trimeric form of ligand bound). The most likely explanation for the cytokine effect is an inhibition of the synthesis of new receptors.
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PMID:Tumor necrosis factor and interleukin-1 down-regulate receptors for substance P in human astrocytoma cells. 172 42

[125I]Bolton Hunter conjugate of substance P ([125I]BHSP) can bind to human astrocytoma membranes in a monophasic and saturable manner with a Kd of 0.57 +/- 0.17 nM and a Bmax of 67.8 +/- 5.5 fmol/mg protein. The rank order of potency of tachykinins and related analogues as inhibitors of [125I]BHSP binding to astrocytoma membranes and intact cells correlated with their relative abilities to stimulate uridine incorporation into nucleic acid. The observed specificity pattern conformed to that reported for the NK1 tachykinin receptor with SP much greater than eledoisin greater than neurokinin A greater than neurokinin B and [Glp6, L-Pro9]SP(6-11) much greater than [Glp6, D-Pro9]SP(6-11).
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PMID:Functional substance P receptors on a human astrocytoma cell line (U-373 MG). 254 4

Forty nine gliomas were analysed for the following neuropeptides: somatostatin (SS), substance P (SP), neurotensin (NT) and vasoactive intestinal polypeptide (VIP) and the pituitary peptide, adrenocorticotrophin (ACTH). A significant amount of authentic SS was found in a medulloblastoma, and low concentrations of SP and NT immunoreactivity in an ependymoma and cerebellar astrocytoma respectively. The majority of the other gliomas did not contain detectable levels of these five neuropeptides. Low levels of neuropeptides were found in some specimens probably due to contamination with cerebral cortex.
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PMID:Neuropeptides in gliomas: identification of somatostatin 14 in a medulloblastoma. 287 61


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