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)

We describe a rapid method for the preparation and binding site labeling of cryostat sections for use in light microscopy. Instead of using antibodies to bind to specific sites, substance P, delta-sleep-inducing peptide, oxytocin, and dopamine were covalently attached to BSA and then the BSA-ligand complex was adsorbed on 5-nm colloidal gold particles. Bioassays carried out on isolated organs indicated that the physiological activity of the ligand GPL complex was maintained. Most of the technical steps included use of an ordinary microwave oven (MWO), with tissues exposed for less than 1 min in any given step. Cryostat sections of unfixed rat brain were pre-incubated for 50 sec in the MWO in a Tris-buffered solution (pH 7.4) containing 1.5% BSA, then further incubated for 50 sec in the MWO in Tris-buffered solution containing 1% gelatin and the diluted colloidal gold suspension. After washing, the preparations were postfixed for 30 sec in the MWO in 5% formaldehyde solution, pH 7.4. Finally, the cell-bound gold particles were enlarged by a silver-enhancing process and counterstained. Preparations observed at high magnification provided excellent resolution of the cell binding sites. Positive and negative controls performed by addition of BSA-conjugated ligands to the pre-incubation and incubation medium, and displacement of the markers by an excess of unbound ligand in the pre-incubation or the incubation medium, showed the specificity of the tissue labeling.
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PMID:Microwave-aided binding of gold-protein-ligand (GPL) complexes. Light microscopic observations in the rat brain. 137 31

Substance P (SP) is one of the endogenous tachykinin peptides implicated in neurogenic inflammation and may be critically involved in diseases as diverse as asthma, arthritis and inflammatory bowel disease. The current study was initiated to identify a rich source of SP receptor that would be amenable for studying the regulatory mechanism of the receptor. By using a radioligand receptor binding technique, sheep ileal smooth muscle membranes showed a much higher density of [3H]SP specific binding than other non-neural rat or sheep tissues and organs surveyed. Of the protease inhibitors tested, only phosphoramidon, a specific and potent enkephalinase inhibitor, prevented the degradation of [3H]SP and enhanced [3H]SP binding to the membrane. [3H]SP binding to the specific binding sites in the membranes was time-dependent and reached a steady state after 60 min at 22 degrees C in 25 mM Tris.NH3 (pH 7.4). Calcium and magnesium ions enhanced [3H]SP specific binding. Saturation binding studies showed that the dissociation constant (KD) and the density of maximum binding sites for [3H]SP specific binding were 0.54 nM and 83 fmol/mg of protein, respectively. The specificity of the [3H]SP labeled sites was SP greater than (4-11) SP greater than eledoisin greater than spantide greater than neurokinin-A greater than D-Pro2D-Phe7D-Trp9-SP. Neurokinin-B and senktide showed no inhibition of [3H]SP binding.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Identification and characterization of the substance P receptor in sheep intestinal smooth muscle membranes. 169 67

The presence of substance P in numerous mammalian pineal glands prompted us to search for its binding sites in the bovine pineal gland. The binding assays to pineal membrane were carried out in polypropylene microcentrifuge tubes in a final volume of 500 microliters of 50 mM Tris-HCl buffer (pH 7.4) containing aliquots of 200-500 micrograms protein, 0.02% BSA, 6 micrograms/ml chymostatin, 4 micrograms/ml leupeptin, 40 micrograms/ml bacitracin, 5 mM MnCl2, and 50 microliters of [3H]substance P (3H-SP, 45.7 Ci/mmol to yield a final concentration of 0.02-20 nM) to start the reactions, which were incubated for 20 min at 20 degrees C. The reactions were terminated by centrifugation in a Fisher Microcentrifuge Model 235A for 30 seconds at 13,000 X g, and the pellets were washed twice with 1 ml of ice-cold 50 mM Tris-HCl buffer containing 0.02% BSA, 6 micrograms/ml chymostatin, 4 micrograms/ml leupeptin, 40 micrograms/ml bacitracin, 5 mM MnCl2, 120 mM NaCl, 5 mM KCl, 1 mM MgCl2, and 1 mM CaCl2. The bottoms of the tubes were cut, the membrane pellets were dissolved in 5 ml of Triton X-100/toluene fluor (1:3) scintillation fluid, and the radioactivity was counted. The specific [3H]-substance P binding at 1-2 nM was 40-50% of the total binding, and the non-specific binding was assessed by using 2 microM of unlabelled substance P. These studies identified in bovine pineal gland a high affinity receptor site for [3H]SP with a KD value of 0.43 nM and a Bmax value of 71.14 fmol/mg protein. The relative affinity of various substance P analogues or fragments was: substance P greater than physalaemin greater than SP2-11 greater than SP3-11 greater than SP4-11 greater than SP6-11 greater than substance K = eledoisin greater than kassinin greater than SP7-11 greater than SP free acid. Substance P did not alter the basal or the norepinephrine-induced stimulation of the activity of serotonin N-acetyltransferase in rat pineal gland in culture.
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PMID:Studies on high-affinity [3H]substance P binding sites in bovine pineal gland. 243 Jul 88

Substance P (SP) is an important neuropeptide that has been implicated in several physiological processes, and it is necessary to devise an analytical procedure to measure endogenous SP with a combination of high sensitivity and maximum molecular specificity. However, the unique chemical nature of SP (polarity, chemical stability, ease of oxidation, peptide bond lability) plays a significant role in its analysis, such as in receptor assays, immunoassays, chromatography, and mass spectrometry. In this study, we evaluated in polypropylene and glass assay tubes the effects on the recovery and stability of tritiated SP ([3H]SP) of several pertinent experimental parameters such as buffer, pH, multiple freeze-thaw cycles, and incubation temperature and time. Bovine serum albumin (BSA) effectively reduced the absorption of [3H]SP to polypropylene and glass tube surfaces. Following multiple (6X) freeze-thaw cycles of solutions in BSA-precoated tubes, the recovery of radioactive [3H]SP remained high (greater than 75%) after the last cycle, whereas recovery was minimal in uncoated or siliconized glass tubes. A high level of radioactivity recovery was maintained for 14 days of storage of [3H]SP in triethylamine formate (TEAF) solution in BSA-precoated tubes at 4 and -20 degrees C, but decreased at 37 degrees C to less than 80% in only 3 h. Following storage in Tris-HCl (pH 7.4) buffer, a combination of HPLC and mass spectrometric analyses revealed that a significant amount of peptide bond cleavage occurred to produce the two peptides ArgProLys (RPK) and ArgProLysProGlnGln (RPKPQQ), with only a small amount of remaining intact SP. That decomposition was not observed in triethylamine formate TEAF (pH 3.14) buffer solutions.
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PMID:Chemical degradation of 3H-labeled substance P in tris buffer solution. 246 Nov 23

The binding of substance P (SP), a positively charged neurotransmitter peptide, to neutral and to negatively charged phospholipids has been investigated by means of a monolayer technique. Monolayers formed at room temperature from 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol (POPG) or 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC), or mixtures of the two, were maintained throughout the course of a binding experiment at a constant surface pressure while the monolayer surface area was monitored. Injection of SP into the aqueous subphase (154 mM NaCl, 10 mM Tris adjusted to pH 7.4) led to an expansion of the monolayer surface area that was attributed to a spontaneous insertion of SP between the lipid molecules. A quantitative evaluation of the area increase at constant pressure yielded SP insertion isotherms that showed that levels of SP insertion increased directly with the monolayer POPG content and decreased to negligible levels at surface pressures above 35 +/- 1 mN/m. If electrostatic effects were ignored, these data showed biphasic behavior in Scatchard plots. The apparent binding constants ranged, at 20 mN/m, from (3.2 +/- 0.3) X 10(4) M-1 for 100% POPG monolayers to (2.0 +/- 0.05) X 10(3) M-1 for 25% POPG/75% POPC monolayers. At 32 mN/m, a monolayer surface pressure that mimics bilayer conditions, the apparent binding constant for a 100% POPG monolayer was measured to be (1.1 +/- 0.05) X 10(3) M-1. However, for a monolayer containing only 25% charged lipids, corresponding to a natural membrane composition, K app at 32 mN/m was estimated to be at most 41 M-1.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Binding of a neuropeptide, substance P, to neutral and negatively charged lipids. 247 49

Angiotensin-converting enzyme, although most prominent in vascular endothelium, has been identified in numerous tissues. Recent studies have indicated that several hormones, including glucocorticoids and thyroid hormone, may affect the activity of this enzyme. In the present study, angiotensin-converting enzyme was examined in homogenates of cultured human skin fibroblasts. Angiotensin-converting enzyme activity was measured by a radiometric assay using [Glycine-1-14C] Hippuryl-L-histidyl-L-leucine (1.1 mmol/L) as substrate, and was expressed as nmol hippuric acid formed per minute/mg protein. Angiotensin-converting enzyme was identified in all five cell strains tested, and the activity observed was 0.97 +/- 0.18 nmol/min/mg protein (mean +/- SE). The optimum pH was between 6.9 and 7.6, and optimum temperature was 37 degrees C, with loss of activity of 55 degrees C and higher. Buffer strength was optimized at Tris 0.025 mol/L, and 1.0 mol/L NaCl. Activity increased linearly with protein concentration and with time, and the Km = 1.14 mmol/L. The most potent inhibitor of fibroblast ACE was captopril (SQ 14,225) with an IC50 = 10(-10) mol/L; other inhibitors included SQ 20,881, EDTA, and phenanthroline. Competitive substrates included angiotensin-I, substance P, and bradykinin. Four hormones, T3 (10(-9)-10(-7) mol/L), 1,25 (OH)2D3 (10(-8)-10(-7) mol/L), dexamethasone (10(-7)-10(-6) mol/L), and a synthetic androgen, R1881 (10(-8)-10(-7) mol/L) were incubated with cells for 72 hours. In all incubations, there was no significant effect on cellular ACE activity induced by any agent. Angiotensin-converting enzyme activity in serum free media was less than 1% of cell activity and was unaltered by hormone treatment.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Angiotensin-converting enzyme: characteristics in human skin fibroblasts. 302 Mar 42

A comparison was made of the actions of substance P, prostaglandin F2 alpha (PGF2 alpha), histamine and carbachol on the membrane potential and conductance of the longitudinal smooth muscle of the taenia of the guinea-pig caecum using the double sucrose gap apparatus. The increases in conductance produced by the four drugs during matched depolarizations in the sucrose gap were not significantly different and they were substantially larger than the increase in conductance brought about during the same depolarization produced by passing outward current. In sucrose-substituted, Na- and Cl-deficient solution the increases in conductance and depolarization due to carbachol, substance P, and PGF2 alpha were attenuated to a similar extent. The depolarization due to histamine under these conditions was reduced to a significantly greater extent than that due to carbachol. In Tris-benzene-sulphonate substituted Na- and Cl-deficient solution the responses due to carbachol and histamine were attenuated to a similar extent. This suggests that sucrose addition may have a specific effect on the histamine response. In Tris-substituted Na-deficient solution the increases in conductance and depolarization produced by substance P, histamine and carbachol were attenuated to a similar extent. The depolarization due to PGF2 alpha was reduced by a significantly greater amount which may be due to unmasking an inhibitory effect that was sometimes apparent in normal solution. In benzenesulphonate-substituted, Cl-deficient solution the increases in conductance and depolarizations produced by moderate concentrations of PGF2 alpha, histamine and carbachol were attenuated to a similar extent. The response to substance P was little affected. In glucuronate-substituted, Cl-deficient solution the increases in conductance and depolarizations due to substance P and carbachol were attenuated to a similar extent. This result, and the observation that the depolarization to large concentrations of carbachol was not reduced in benzenesulphonate-substituted, Cl-deficient solution, suggest that benzenesulphonate interferes with the reactions of the non-peptide stimulants with their respective receptors. The similarities in the effects of activating the four types of receptor under some conditions could be explained if they all acted on the same population of receptor-operated channels. In addition it seems that PGF2 alpha acts also on a population of inhibitory receptors, sucrose interferes with histamine's action, and benzenesulphonate interferes with the reactions of non-peptide stimulants with their respective receptors.
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PMID:Comparison of the excitatory actions of substance P, carbachol, histamine and prostaglandin F2 alpha on the smooth muscle of the taenia of the guinea-pig caecum. 619 69

An enzyme activity capable of hydrolysing the neuroactive undecapeptide substance P (SP) between its Phe7-Phe8 residues was purified from the membrane-bound fraction of human spinal cords. The enzyme preparation yielded was compared with a previously described SP-hydrolysing enzyme from human cerebrospinal fluid (CSF) with regard to inhibition profile, protein chemical properties and kinetics. In addition, the results were compared with those of bovine pancreatic chymotrypsin (a serine protease that cleaves the carboxy-terminal side preferentially at hydrophobic amino acids). The SP peptidase activity was extracted from human spinal cords with 1% Triton X-100 in 20 mM Tris-HCI pH 7.8. After ion exchange chromatography (DEAE-Sepharose) where the enzyme activity was separated from other proteins by gradient elution, the pooled enzyme fraction was further purified by molecular sieving (Sephadex G-50). The enzyme activity was finally recovered by HPLC molecular sieving (Superdex 75 HR 10/30) using a new preparative system, AKTA-purifier, controlled by UNICORN software version 2.20.
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PMID:Purification of substance P endopeptidase (SPE) activity in human spinal cord and subsequent comparative studies with SPE in cerebrospinal fluid and with chymotrypsin. 1007 55

The present study demonstrates a procedure for extraction and determination of stratum corneum amines in the living animal. A nonleaky well, containing 10 mM Tris-HCl buffer, pH 7.0, was constructed on the shaved backs of anesthetized animals. It was found that Ser, Ala, Gly and Pro are mainly released from the stratum corneum of 4-month-old guinea pigs, and in 2-month-old rats, Gly, Ser and Arg show the highest degree of release. Much lower amino acid concentrations were observed in 20-month-old rats. This was also reflected by the high levels of fluorescamine-reactive substances released from young rat skin as compared to the old animals. The release of the neuropeptide substance P into the aqueous medium was increased 3.2 times upon heat stimulus as compared to control skin. Amines and other compounds released from the skin may serve as markers for skin aging or for certain skin disorders, leading to a new approach for their treatments.
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PMID:Release of amino acids, fluorescamine-reactive substances and substance P from the epidermis of the living animal. 1032 89

Alzheimer's disease (AD) is primarily nonfamilial or sporadic (SAD) in origin, although several genetic linkages are reported. Tissues from AD patients contain fibrillar plaques made of 39 to 43 amino acid-long amyloid beta peptide (AbetaP), although the mechanisms of AbetaP toxicity are poorly understood. AbetaP(1-40) is the most prevalent AbetaP present in the neuronal and non-neuronal tissues from SAD patients. AbetaP(1-40) toxicity has been examined mainly after prolonged incubation and correlates with the age and fibrillar morphology of AbetaP(1-40). Globular and nonfibrillar AbetaPs are released continually during normal cellular metabolism; they elevate cellular Ca(2+) and form cation-permeable channels. However, their role in cellular toxicity is poorly understood. We have used an integrated atomic force and light fluorescence microscopy (AFM-LFM), laser confocal microscopy, and calcium imaging to examine real-time and acute effect of fresh and globular AbetaP(1-40) on cultured, aged human, AD-free fibroblasts. AFM images show that freshly prepared AbetaP(1-40) in phosphate-buffered saline (PBS) are globular and do not form fiber for an extended time period. AbetaP(1-40) induced rapid structural modifications, including cytoskeletal reorganization, retraction of cellular processes, and loss of cell-cell contacts, within minutes of incubation. This led to eventual cellular degeneration. AbetaP(1-40)-induced degeneration was prevented by anti-AbetaP antibody, zinc, and Tris, but not by tachykinin neuropeptides. In Ca(2+)-free extracellular medium, AbetaP(1-40) did not induce cellular degeneration. In the presence of extracellular Ca(2+), AbetaP(1-40) induced a sustained increase in the cellular Ca(2+). Thus, short-term and acute AbetaP(1-40) toxicity is mediated by Ca(2+) uptake, most likely via calcium-permeable AbetaP pores. Such rapid degeneration does not require fibrillar plaques, suggesting that the plaques may not have any causative role.
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PMID:Fresh and nonfibrillar amyloid beta protein(1-40) induces rapid cellular degeneration in aged human fibroblasts: evidence for AbetaP-channel-mediated cellular toxicity. 1083 46


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