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)

The present investigation examined the effects of neonatal and adult 6-hydroxydopamine (6-OHDA)-induced lesions of dopaminergic neurons on opioid and tachykinin peptides and their gene expression in the rat basal ganglia. This work was undertaken to determine if changes in these neuropeptide systems were contributing to the differing behavioral responses observed between neonatally and adult-lesioned rats after dopamine agonist administration. [Met5]Enkephalin (ME) content was increased in striatal tissue from both 6-OHDA-lesioned groups when compared with unlesioned controls. Dynorphin-A (1-8) content was not altered by the 6-OHDA lesions. The tachykinin peptides substance P and neurokinin A were significantly decreased in level in the striatum and substantia nigra of neonatally lesioned rats, but not in the adult-lesioned rats, when compared with unlesioned controls. Proenkephalin mRNA abundance (quantified by an RNA-cDNA hybridization technique) and precursor level (as reflected by cryptic ME content) were increased in the striatum of both neonatally and adult-lesioned rats. The abundance of preprotachykinin mRNA coding for the tachykinin peptides was markedly decreased in the neonatally lesioned rats, whereas only a small reduction was observed in the adult-lesioned rats. These results suggest that destruction of dopamine-containing terminals with 6-OHDA elevates the level of ME by accelerating transcriptional and/or translational processes; conversely, the reduced content of tachykinins in neonatally lesioned rats may be due to a reduction in such processes. Thus, preproenkephalin-A and preprotachykinin gene expression are differentially regulated after lesioning of catecholamine-containing neurons, an observation suggesting a close functional relationship among these neurotransmitter systems. Furthermore, of the peptides studied, only levels of the tachykinin peptides were differentially altered in the striatum and substantia nigra of the neonatally lesioned rats compared with adult-lesioned rats; therefore, these peptides may be associated with the distinctive behavioral differences between neonatally and adult 6-OHDA-lesioned rats given dopamine agonists.
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PMID:Neonatal and adult 6-hydroxydopamine-induced lesions differentially alter tachykinin and enkephalin gene expression. 288 4

Smooth muscle cells were isolated from the fundus of the canine gallbladder and examined for the presence of opioid receptors. The cells contracted in a concentration-dependent manner in response to three opioid peptides (Met-enkephalin, dynorphin1-13 and Leu-enkephalin), which are known derivatives of opioid precursors present in myenteric neurons of the gut. The order of potency was Met-enkephalin greater than dynorphin1-13 greater than Leu-enkephalin. The contractile response to opioid agonists was selectively inhibited by opioid antagonists (naloxone and Mr2266) but not by muscarinic, CCK/gastrin or tachykinin antagonists. Equivalent responses to the three opioid peptides exhibited differential sensitivity to preferential antagonists of mu (naloxone) and kappa (Mr2266) opioid receptors consistent with the presence of the three main types of opioid receptors (mu, delta and kappa) on canine gallbladder muscle cells.
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PMID:Characterization of opioid receptors on isolated canine gallbladder smooth muscle cells. 289 8

Immunohistologic localization of tyrosine hydroxylase (TOH), dopamine-beta-hydroxylase (DBH) and selected neuropeptides (vasoactive intestinal polypeptide, gastrin-releasing peptide (GRP)/bombesin, substance P, Leu-enkephalin, Met-enkephalin, dynorphin B, neuropeptide Y (NPY), somatostatin) was used to investigate the innervation of the small bowel in a rat model of diabetic autonomic neuropathy. Paravascular mesenteric nerves (extrinsic) and intramural nerves of chronically (12-18 month) diabetic rats were characterized by the presence of numerous, markedly swollen dystrophic axons which stained intensely for TOH and DBH. The peptidergic complement of axons, however, showed no evidence of comparable dystrophic axonopathy.
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PMID:Effects of chronic experimental streptozotocin-induced diabetes on the noradrenergic and peptidergic innervation of the rat alimentary tract. 290 98

A dipeptidyl carboxypeptidase, which cleaved the Gly3-Phe4 bond of enkephalins, was purified from guinea pig serum 420-fold. The optimum pH of the enzyme was in the neutral range (pH 7.25), and the molecular weight was estimated to be approx. 280,000. The enzyme hydrolyzed Met- and Leu-enkephalin with Km values of 0.30 and 0.50 mM, respectively. The enzyme was inhibited by metal chelators and p-chloro-mercuribenzoate. Captopril showed high inhibitory potency, while phosphoramidon and Phe-Ala showed no effect on the enzyme activity. Therefore, the obtained enzyme can be classified as an angiotensin-converting enzyme (EC 3.4.15.1). Among the bioactive peptides examined, bradykinin and angiotensin I were hydrolyzed by the enzyme. Angiotensin III showed a stronger inhibitory effect than that of angiotensin II. Substance P, gastrin I, and secretin were also inhibitory toward the enzyme activity. On high-performance liquid chromatography analysis, Met-enkephalin-Arg6-Phe7 and Leu-enkephalin-Arg6 were cleaved sequentially at the second peptide bond of the C terminus. Thus, the dipeptidyl carboxypeptidase in guinea pig serum may play a role not only in the angiotensin-bradykinin system but also in the metabolism of circulating enkephalins and other bioactive peptides.
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PMID:Enkephalin-degrading dipeptidyl carboxypeptidase in guinea pig serum: its properties and action on bioactive peptides. 299 Mar 46

Two closely related Cl(-)-activated arginyl aminopeptidases (I and II) were purified from a soluble extract of postmortem human cerebral cortex by anion-exchange chromatography and preparative gel electrophoresis. The electrophoretic mobility of II was approximately 80% that of I; the molecular mass of both enzymes was approximately 70 kilodaltons (kDa) (gel filtration). The aminopeptidase action of I and II on aminoacyl-7-amido-4-methylcoumarin (AMC) substrates was restricted to the Arg and Lys derivatives. Both enzymes had significant endopeptidase activity, hydrolysing several biologically active peptides including neurotensin, bradykinin, angiotensin-I, substance P, luliberin, and somatostatin at internal bonds. Other peptides [Leu-enkephalin, proctolin, thyroliberin, adrenocorticotropin18-39 (ACTH18-39), ACTH11-24, and dynorphin (1-13)] were not appreciably hydrolysed. The amino- and endopeptidase activities had pH optima at 6.5 and 7, respectively, and were both inhibited by metal ion chelators and sulphydryl group blocking agents. The aminopeptidase activity was stimulated 20-fold by Cl- ions, whereas the endopeptidase activity was unaffected by the latter. Km values for neurotensin degradation were 20 microM (I) and 37 microM (II) and for Arg-AMC hydrolysis they were 167 microM (I) and 125 microM (II). The endopeptidase activity was not inhibited by the aminopeptidase inhibitors arphamenine or bestatin (IC50 = 9 nM and 0.1 microM, respectively, with Arg-AMC substrate).
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PMID:Purification and characterization of two soluble Cl(-)-activated arginyl aminopeptidases from human brain and their endopeptidase action on neuropeptides. 265 16

A neuroendocrine skin carcinoma cell line MKL-1 has been established from a nodal metastasis in a 26-year-old patient. The line grows as irregularly outlined, loosely packed floating aggregates lacking central necrosis. MKL-1 is hyperdiploid and has a mean doubling time of 120 hours. Xenografts of 2 X 10(7) MKL-1 cells produce tumors in nude mice at 4 to 6 weeks after subcutaneous inoculation. The xenografts were morphologically indistinguishable from the original skin primary and the nodal metastasis. Electron microscopy revealed sparse membrane-bound neurosecretory granules, and conspicuous, paranuclear aggregates of intermediate filaments. Immunohistochemical study showed diffuse and consistent staining with neuron-specific enolase, while bombesin, adrenocorticotrophic hormone, Leu-enkephalin, substance P, and vasoactive intestinal polypeptide displayed heterogeneous and variable expression. Uniform staining of all cells appearing as cytoplasmic fibrils and paranuclear aggregates was noted with antibodies to cytokeratin. Appreciable amounts of cytokeratin polypeptides 8, 18, and 19 and IT protein were seen on two-dimensional gel electrophoresis of cytoskeletal preparations from MKL-1 cells and from tumor-rich frozen sections. Immunostaining also showed coexpression of neurofilaments arranged in paranuclear aggregates; gel electrophoresis and immunoblotting demonstrated the presence in MKL-1 cells of prominent amounts of the small neurofilament polypeptide. Focal expression of desmoplakin was noted in the xenografts. The cells reacted with monoclonal antibodies anti-Leu-7 and anti-Leu-M1 but did not react with antibodies to human lymphocyte antigens (HLA)-A, HLA-B, and HLA-C. Cytogenetic analysis revealed the presence of 3 chromosomally abnormal cell lines with the majority of metaphase cells demonstrating a gain of an isochromosome of the short arm of chromosome 5. Thus, MKL-1 cell line shares several characteristics with small cell neuroendocrine bronchopulmonary carcinoma cell lines but shows distinct cytogenetic abnormalities.
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PMID:Establishment and characterization of a neuroendocrine skin carcinoma cell line. 354 33

Carcinoid tumors of the middle ear are rare, with only three previously reported cases. The authors report the light and electron microscopic and immunohistochemical features of two carcinoid tumors that occurred in a 34-year-old female and a 21-year-old male. Both presented with unilateral hearing loss. By light microscopic examination, both were characterized by trabecula of tall columnar cells with basal nuclei and no mitotic activity. Electron microscopic examination demonstrated large numbers of pleomorphic neurosecretory granules, perinuclear aggregates of intermediate filaments, cell junctions, and surface microvillous processes. Some cells contained intermediate filaments forming tonofilaments and lacked secretory granules. These cells stained for cytokeratin by immunoperoxidase and separated the neuroendocrine cells from the underlying basal lamina. The cells in this tumor stained for the molluscan cardioexcitatory peptide. Cells in both tumors also stained for pancreatic polypeptide. Neither case stained for lysozyme, insulin, glucagon, somatastatin, gastrin, substance P, thyroid-stimulating hormone, adrenocorticotropic hormone, Met-enkephalin, Leu-enkephalin, neuropeptide Y, peptide YY, neurotensin, Bombesin, serotonin, neuron-specific enolose, glial and neural filaments, S-100 protein, cholecystokinin, beta-endorphin, beta-human chorionic gonadotropin, luteinizing hormone/follicle-stimulating hormone, vasoactive intestinal polypeptide, prolactin or calcitonin. Carcinoid tumor of the middle ear can be distinguished from paraganglioma and middle ear adenoma.
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PMID:Carcinoid tumors of the middle ear. 357 33

Neuropeptide Y (NPY), substance P (SP), vasoactive intestinal polypeptide (VIP), calcitonin gene-related peptide (CGRP), lysyl-bradykinin, somatostatin, Met- and Leu-enkephalin were tested for their smooth muscle activity in isolated human mesenteric arteries and veins. Only NPY regularly contracted both arteries and veins. Alpha-adrenergic and 5-HT2 antagonists did not affect the response. Somatostatin contracted the veins, but not the arteries, in a variable but concentration-dependent way. The other neuropeptides were without contractile effect. CGRP, bradykinin, and SP regularly dilated, in a concentration-dependent way, both arteries and veins precontracted with prostaglandin F2 alpha or uridine triphosphate. CGRP and bradykinin were the most potent dilators. VIP and somatostatin usually caused a moderate dilatation in the arteries, whereas in the veins, somatostatin was without dilatory effect and the VIP-induced dilatation was irregular. In both types of vessels Met-enkephalin seldom gave any significant dilatation, and no response occurred in the presence of Leu-enkephalin or NPY. The SP-antagonist (D-Arg, D-Trp, Leu)-SP (spantide) caused a dextal shift of the concentration-response curves for SP, in the case of the arteries also including a reduced maximum effect.
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PMID:Contractile and dilatory action of neuropeptides on isolated human mesenteric blood vessels. 358 45

A porcine brain dipeptidyl-aminopeptidase (DAP) has been purified more than 2400-fold from a crude mitochondrial fraction containing synaptosomes. This enzyme catalyzes the release of free Tyr-Gly from Leu-enkephalin (Km = 2.5 microM) with an optimal activity between pH 6.0 and pH 8.0. The enzyme appears homogeneous as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis devoid of detectable contaminating aminopeptidase activities. The native enzyme is a monomeric protein with a molecular weight of 51,000 +/- 1,000 and an isoelectric point of 4.6 +/- 0.1. This enzyme cosediments with synaptosomes on a Ficoll-sucrose gradient and is partially associated with synaptic plasma membranes. Its activity is inhibited by the metal-chelating agents ethylenediaminetetraacetate and o-phenanthroline. It is not inhibited by the OH-reactive agent phenylmethanesulfonyl fluoride and SH-reactive agents such as p-(chloromercuri)benzoate and N-ethylmaleimide. Among the various biologically active peptides tested, the purified enzyme releases efficiently the N-terminal dipeptide moiety from enkephalins, Trp-Met-Asp-Phe-NH2 (CCK4), and Gly-Trp-Met-Asp-Phe-NH2 (CCK5). At variance, the native peptides CCK8, substance P, neurotensin, and angiotensin II are not cleaved by the DAP. This enzyme is different from other unspecific DAPs, as well as from enkephalin-degrading DAPs previously reported, by its molecular weight and substrate specificity.
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PMID:Purification and characterization of an enkephalin-degrading dipeptidyl-aminopeptidase from porcine brain. 381 77

Rat brain aminopeptidase activity was solubilized from membranes by incubation with thiols. This novel procedure resulted in the release of the same two aminopeptidases (MI and MII) previously shown to be solubilized by the nonionic detergent Triton X-100. The solubilized aminopeptidases MI and MII were resolved by ion-exchange chromatography and further purified by hydroxylapatite chromatography. Aminopeptidase MI was shown to hydrolyze only the beta-naphthylamides of arginine and lysine whereas aminopeptidase MII exhibited a broad specificity with respect to amino acid beta-naphthylamides. Only aminopeptidase MII hydrolyzed Leu-enkephalin at a significant rate, indicating that this enzyme can account for the membrane-bound enkephalin aminopeptidase activity. The enkephalin-degrading aminopeptidase is potently inhibited by opioid (alpha-neo-endorphin and dynorphin) as well as nonopioid (substance P, somatostatin, and angiotensin I) peptides in the range of 0.2-2.0 microM. The regional distribution of aminopeptidases MI and MII in rat brain are rather different, with aminopeptidase MII distribution more closely paralleling the distribution of opiate receptors.
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PMID:Characterization of membrane-bound aminopeptidases from rat brain: identification of the enkephalin-degrading aminopeptidase. 388 43


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