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)

Extensive evidence implicates Substance P [SP(1-11)] as a primary afferent neurotransmitter or modulator of nociceptive information, and there is increasing evidence that the excitatory amino acids aspartate (Asp) and glutamate (Glu) may also act as nociceptive neurotransmitters. We have previously demonstrated that nociceptive stimulation (metatarsal injection of formalin) caused a tetrodotoxin (TTX)-sensitive release of Asp and a TTX-insensitive release of Glu from the dorsal spinal cord. We have also shown release of Asp and Glu following the direct infusion of SP(1-11), suggesting that formalin-induced Asp or Glu changes could be secondary to an initial release of SP(1-11). In contrast to nociception, pretreatment with TTX, reported here, had no effect on the SP(1-11)-induced release of Asp, suggesting a presynaptic mechanism. Behavioral experiments, in both our laboratory, and others, now suggest that the N-terminal products of SP metabolism play a distinct role in the modulation of SP(1-11) nociception, possibly through an interaction with an opiate receptor. To test the hypothesis that N- and C-terminal fragments of SP produce opposite effects on biochemical events potentially involved in nociception, we compared the effects of infusion of the N-terminal metabolite SP(1-7) and the C-terminal metabolite SP(5-11) on changes in the ECF concentration of amino acids in the spinal cord as a measure of their apparent release, using microdialysis. Intradiaylsate infusion of SP(5-11) increased the release of Asp, Glu, asparagine (Asn), glycine (Gly), and taurine (Tau). The changes in Asp, Glu, and Tau were similar in direction and magnitude to changes produced by SP(1-11) or formalin injection, further supporting the hypothesis that the C-terminal is responsible for the nociceptive effects of SP(1-11). In contrast, infusion of SP(1-7) significantly decreased the release of Asn, Tau, Glu, and Gly. This inhibition of amino acid release is consistent with the hypothesis that N-terminal metabolites produce opposite effects to those of C-terminal metabolites of SP(1-11). The decreases in Glu, Asn, Gly, and Tau following SP(1-7) infusion were significantly reduced by i.p. or intradialysate naloxone. Systemic naloxone had no significant effects on the SP(5-11)-induced amino acid changes; however, it did inhibit the SP(1-11)-induced increase in Asp and Glu. Intradialysate naloxone had no effect on the SP(1-11)-induced increases.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Differential effects of C- and N-terminal substance P metabolites on the release of amino acid neurotransmitters from the spinal cord: potential role in nociception. 169 75

The effects of dorsal root stimulation and of substance P (SP), neurokinin A (NKA), and calcitonin gene-related peptide (CGRP) on the basal release of 9 endogenous amino acids, including glutamate (Glu) and aspartate (Asp), have been investigated using the rat spinal cord slice-dorsal root ganglion preparation and high-performance liquid chromatography with fluorimetric detection. High-intensity repetitive electrical stimulation of a lumbar dorsal root produced a Ca2(+)-dependent increase in the basal release of Asp, Glu, glycine (Gly), serine (Ser), and threonine (Thr). Low concentrations of SP (2 x 10(-7) M) caused a selective increase in the rate of basal release of Glu, whereas higher concentrations (1-5 x 10(-6) M) produced, in addition, an increase in the basal release of Asp. The SP-induced increase of Glu persisted in the absence of external Ca2+, but the effect was blocked by (D-Arg1, D-Pro2, D-Trp7,9, Leu11)-SP, an SP analog claimed to be an antagonist of the synthetic SP. NKA (5 x 10(-7) - 10(-6) M), a related tachykinin coexpressed with SP in primary sensory neurons, enhanced the basal release of Gly. CGRP (10(-7) M) caused a significant, largely Ca2(+)-independent increase in the basal release of Glu and Asp and a decrease in asparagine. SP and CGRP potentiated the electrically evoked release of Glu and Asp. Neonatal capsaicin treatment did not significantly alter the basal efflux of 9 endogenous amino acids from the spinal slices, but it prevented the dorsal root stimulation-evoked release of Asp, Glu, Gly, and Thr and the SP-induced increase in the basal release of Glu. However, the effect of CGRP was not significantly modified by the capsaicin treatment. These results indicate that tachykinins (SP and NKA) and CGRP are capable of modulating the basal and electrically evoked release of endogenous Glu and Asp, and these actions may provide an important mechanism by which the peptides contribute to the regulation of the primary afferent synaptic transmission. The enhancement of the basal and the dorsal root stimulation-evoked release of Glu and Asp by tachykinins and CGRP may have important physiological implications for strengthening the synaptic connections in the spinal dorsal horn.
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PMID:Tachykinins and calcitonin gene-related peptide enhance release of endogenous glutamate and aspartate from the rat spinal dorsal horn slice. 169 54

Amino acids are potential components of oral rehydration solutions for infants, which could combine with glucose to further stimulate intestinal Na+ and water absorption. L-Glutamine, the principal fuel of the intestine, stimulates neutral NaCl absorption and enhances enterocyte DNA synthesis, but is unstable in solution. L-Asparagine (ASN), a more stable amino acid with similar structure to L-glutamine, also stimulates enterocyte proliferation. We determined the effects of ASN on electrolyte transport across piglet jejunum in Ussing chambers. Mucosal but not serosal ASN produced electrogenic Cl- secretion (delta JClnet = -1.8 +/- 0.3 microEq/cm2.hr-1). ASN, when added at 0.1 to 30 mM, increased short-circuit current in a dose-dependent manner with a K1/2 of approximately 5 mM and maximal effect at approximately 10 mM. The stimulation of Cl- secretion by ASN was blocked by pretreatment with serosal tetrodotoxin and bumetanide and was inhibited by preincubation with capsaicin (8-methyl-N-vanillyl-6-nonenamide) or substance P. Inhibition of nitric oxide synthesis with the structural analog of L-arginine, NG-monomethyl-L-arginine, reduced ASN-stimulated secretion by > 70%. Additionally, serosal 6-cyanonitro-quinoxaline 2-3-dione, which is a nonspecific blocker of neural non-N-methyl D-aspartate (NMDA) glutamate receptors, fully inhibited the ASN response (IC50 = 10(-6) M). Inhibition was specific for neurally mediated secretion. We found no inhibition of ASN-stimulated secretion by atropine, ketanserin, indomethacin or L-2-amino-5-phosphonovalerate (specific for NMDA receptors). When compared to ASN, L-glutamate was a weaker stimulator of jejunal Cl- secretion.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Asparagine stimulates piglet intestinal Cl- secretion by a mechanism requiring a submucosal glutamate receptor and nitric oxide. 754 37

Hepatitis C virus (HCV) encodes a polyprotein that is processed to produce the structural and nonstructural proteins of the virus. Nonstructural protein 3 (NS3) is a serine proteinase that cleaves the polyprotein to release the NS4A, NS4B, NS5A, and NS5B proteins. To characterize the substrate specificity of NS3, we synthesized by in vitro translation the polyprotein NS2*-NS3-NS4*P that includes 70% of the NS2 protein, the complete NS3 protein, and 25% of the NS4 protein region attached to substance P, an epitope tag. We demonstrated that NS3 cleaves at the NS3/NS4A junction to release the NS4*P protein. Subsequently, we used this reaction to evaluate the importance of conserved amino acids that flank the NS3/NS4A junction. We replaced amino acids in the P6, P1, and P1' positions of the scissile bond of this junction using site-directed mutagenesis. When the P6 aspartic acid was changed to asparagine, lysine, or serine, NS3-mediated cleavage occurred. When threonine in the P1 position was replaced with other polar amino acids or with amino acids having aliphatic side chains, cleavage occurred, although it was not detected when arginine or tyrosine was present. Replacement of serine in the P1' position with other polar amino acids, with amino acids having aliphatic side chains, or with arginine resulted in NS3-mediated cleavage. Thus, since fewer amino acids in the P1 position supported cleavage than in the P6 or P1' positions, the P1 position of the scissile bond may play a more important role in defining the substrate specificity of the HCV NS3 proteinase.
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PMID:Substrate specificity of the NS3 serine proteinase of hepatitis C virus as determined by mutagenesis at the NS3/NS4A junction. 809 50

A dose-dependent immunomodulating effect of synthetic low-molecular weight peptides was found in CBA mice. Talcin and its analogue, rigin, tripeptide SKE, substance P and its analogue, and vasopressin were shown to produce an immunostimulating effect, whereas vasopressin tetrapeptide, arginyl-asparagine, and tripeptide SKD showed an immunosuppressive effect. The immunomodulatory effect of the peptides tested was associated with the presence of amino acids such as arginine, lysine, tyrosine, glutamic acid in their chemical structure. These amino acids are essential in the mechanisms of immune responses.
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PMID:[The peptide modulation of immune reactions]. 832 77

Substance P is an important neuromediator in spinal synaptic transmission, particularly in processing nociceptive afferent information. The effects of substance P are mediated by activation of the neurokinin 1 receptor. Evidence has suggested that excitatory amino acids such as glutamate, and prostaglandins including prostaglandin E2 are involved in the enhanced spinal excitability and hyperalgesia produced by spinal substance P. In the present study, we have demonstrated that intrathecal injection of substance P (20 nmol) in rats chronically implanted with intrathecal dialysis catheters induced a decrease in thermal paw withdrawal latency (before: 10.4+/-0.3 s; after 7.6+/-0.6 s), which was accompanied by an increase in prostaglandin E2 (362+/-37% of baseline), glutamate (267+/-84%) and taurine (279+/-57%), but not glycine, glutamine, serine or asparagine. Intrathecal injection of artificial cerebrospinal fluid had no effect upon the behavior or release. Substance P-induced thermal hyperalgesia and prostaglandin E2 release were significantly attenuated by a selective neurokinin 1 receptor antagonist RP67580, but not by an enantiomer RP68651. However, substance P-induced release of glutamate and taurine was not reduced by treatment with RP67580. SR140333, another neurokinin 1 receptor antagonist, displayed the same effects as RP67580 (i.e. block of thermal hyperalgesia and prostaglandin E2 release, but not release of amino acids). These results provide direct evidence suggesting that the spinal substance P-induced thermal hyperalgesia is mediated by an increase in spinal prostaglandin E2 via activation of the neurokinin 1 receptor. These findings define an important linkage between small afferents, sensory neurotransmitter release and spinal prostanoids in the cascade of spinally-mediated hyperalgesia. The evoked release of glutamate is apparently not a result of activation of neurokinin 1 receptors. Accordingly, consistent with other pharmacological data, acute spinal glutamate release does not contribute to the hyperalgesia induced by activation of spinal neurokinin 1 receptors.
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PMID:Intrathecal substance P-induced thermal hyperalgesia and spinal release of prostaglandin E2 and amino acids. 1007 33

Substance P (SP), a putative nociceptive transmitter, is increased in the CSF of patients with fibromyalgia syndrome (FMS). Because excitatory amino acids (EAAs) also appear to transmit pain, we hypothesized that CSF EAAs may be similarly involved in this syndrome. We found that the mean concentrations of most amino acids in the CSF did not differ amongst groups of subjects with primary FMS (PFMS), fibromyalgia associated with other conditions (SFMS), other painful conditions not exhibiting fibromyalgia (OTHER) or age-matched, healthy normal controls (HNC). However, in SFMS patients, individual measures of pain intensity, determined using an examination-based measure of pain intensity, the tender point index (TPI), covaried with their respective concentrations of glutamine and asparagine, metabolites of glutamate and aspartate, respectively. This suggests that re-uptake and biotransformation mask pain-related increases in EAAs. Individual concentrations of glycine and taurine also correlated with their respective TPI values in patients with PFMS. While taurine is affected by a variety of excitatory manipulations, glycine is an inhibitory transmitter as well as a positive modulator of the N-methyl-D-asparate (NMDA) receptor. In both PFMS and SFMS patients, TPI covaried with arginine, the precursor to nitric oxide (NO), whose concentrations, in turn, correlated with those of citrulline, a byproduct of NO synthesis. These events predict involvement of NO, a potent signaling molecule thought to be involved in pain processing. Together these metabolic changes that covary with the intensity of pain in patients with FMS may reflect increased EAA release and a positive modulation of NMDA receptors by glycine, perhaps resulting in enhanced synthesis of NO.
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PMID:Changes in the concentrations of amino acids in the cerebrospinal fluid that correlate with pain in patients with fibromyalgia: implications for nitric oxide pathways. 1092 13

A bioactive peptide containing a glutamine-linked oligosaccharide was chemo-enzymatically synthesized by use of the solid-phase method of peptide synthesis and the transglycosylation activity of endo-beta-N-acetylglucosaminidase. Substance P, a neuropeptide, is an undecapeptide containing two L-glutamine residues. A substance P derivative with an N-acetyl-D-glucosamine residue attached to the fifth or sixth L-glutamine residue from the N-terminal region was chemically synthesized. A sialo complex-type oligosaccharide derived from a glycopeptide of hen egg yolk was added to the N-acetyl-D-glucosamine moiety of the substance P derivative using the transglycosylation activity of endo-beta-N-acetylglucosaminidase from Mucor hiemalis, and a substance P derivative with a sialo complex-type oligosaccharide attached to the L-glutamine residue was synthesized. This glycosylated substance P was biologically active, although the activity was rather low, and stable against peptidase digestion. The oligosaccharide moiety attached to the L-glutamine residue of the peptide was not liberated by peptide-N(4)-(N-acetyl-beta-D-glucosaminyl) asparagine amidase F.
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PMID:Chemo-enzymatic synthesis of a bioactive peptide containing a glutamine-linked oligosaccharide and its characterization. 1141 Mar 33

The chemo-enzymatic synthesis of a glycopeptide, which involves the chemical synthesis of N-acetylglucosaminyl peptide and the enzymatic transfer of oligosaccharide, is described. The first step of the chemo-enzymatic method is the chemical synthesis of N-acetylglucosaminyl peptide with an N-acetylglucosamine moiety bound to the asparaginyl residue of the peptide by a solid-phase method. The second step is transglycosylation of a complex-type oligosaccharide derived from a glycopeptide to an N-acetylglucosaminyl peptide by endo-beta-N-acetylglucosaminidase of Mucor hiemalis (Endo-M). Peptide T can block HIV infection of human T cells. We added the sialo-complex-type oligosaccharide to chemically synthesized N-acetylglucosaminyl Peptide T using the transglycosylation activity of Endo-M. The glycosylated Peptide T thus produced showed a higher degree of resistance to protease digestion than Peptide T. We also prepared calcitonin glycopeptide. Calcitonin is a calcium-regulating hormone that is widely used in therapy for hypercalcemia, and is glycosylated by the chemo-enzymatic method described above. This glycopeptide demonstrated sufficient physiological activity. Comparison of NMR data between native calcitonin and calcitonin glycopetide revealed that the glycosylation does not affect the binding topology of the peptide. N-Acetylglucosaminyl glutamine was also a good glycoside acceptor of Endo-M. We were able to add the sialo-complex-type oligosaccharide to the glutamine residue of the Substance P neuropeptide using the transglycosylation activity of Endo-M. The glycosylated Substance P was biologically active, although its activity was rather low, and stable against peptidase digestion. The oligosaccharide moiety attached to the l-glutamine residue of the peptide was not liberated by PNGase that liberated asparagine-linked oligosaccharide from glycopeptides.
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PMID:Chemo-enzymatic synthesis of bioactive glycopeptide using microbial endoglycosidase. 1623 37

For the past 30 years, I have worked as a physician-scientist in both the clinic and laboratory setting at a number of university medical schools. Encountering patients in the clinic for whom treatment was not available led me to the laboratory in an attempt to develop the appropriate treatment for future patients. The main focus of my translational research has been the role of fibronectin in corneal epithelial wound healing and the development of fibronectin eyedrops for the treatment of patients with persistent corneal epithelial defects. An extension of this research led to the development of eyedrops containing the synthetic peptide proline-histidine-serine-arginine-asparagine (PHSRN), which corresponds to the second cell-binding site of fibronectin. My clinical experience with fibronectin eyedrops also prompted me to examine the role of the sensory neurotransmitter substance P and insulin-like growth factor-1 (IGF-1) in corneal wound healing, leading to the development of eyedrops containing peptides derived from these agents (peptides FGLM-amide and SSSR, respectively). Although the path from the laboratory to the clinic in these instances has been relatively short, the time required to establish the newly identified treatment modalities in the wider community has been long. In this review, I relate the trajectory of my translational research career.
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PMID:The role of fibronectin in corneal wound healing explored by a physician-scientist. 2285 20


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