Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0043167 (pertussis)
 19,595 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Neuropeptide Y (NPY) and norepinephrine, found colocalized in sympathetic neurons innervating blood vessels, exert synergistic responses on vasoconstriction. To examine the signaling mechanisms involved, free of complications associated with mixed receptor populations, we have established a stable Chinese hamster ovary cell line expressing both Y1-NPY and alpha 1b-adrenergic receptors. Occupation of either receptor species, with 100 nM peptide YY (PYY) or 10 microM phenylephrine (PE), respectively, resulted in a rapid increase in the cytoplasmic free calcium concentration ([Ca2+]i) as assessed with Fura-2/AM. The rise due to PYY, but not that due to PE, was abolished by pretreatment with pertussis toxin. Both responses were largely maintained in the absence of extracellular Ca2+, but abolished by prior depletion of intracellular Ca2+ pools with either thapsigargin or 2,5-di-(t-butyl)-1,4-benzohydroquinone. Using cells prelabeled with myo-[3H]inositol, PE promoted a rapid (5 s) rise in inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) as analyzed by anion-exchange high pressure liquid chromatography, whereas the response to PYY (first significant at > 15 s post-stimulation) was too slow to play a causative role in Ca2+ mobilization. Combination of PE and PYY resulted in increases in [Ca2+]i which were at best additive, whereas they promoted a clearly synergistic rise in Ins(1,4,5)P3 at both 15 and 60 s. Co-stimulation also resulted in a synergistic activation of both protein kinase C (PKC) and [3H]arachidonic acid release. In either instance PYY alone was without effect. The potentiation of arachidonic acid release was abolished by depletion of cellular PKC following chronic treatment with phorbol esters. It is suggested that the ability of PYY to mobilize Ca2+ in an Ins(1,4,5)P3-independent fashion minimizes the functional importance of the capacity to potentiate PE-stimulated Ins(1,4,5)P3 generation. Instead the major consequences of the synergistic activation of phospholipase C are mediated via PKC, the other route of the signaling pathway.
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PMID:Synergistic interaction of Y1-neuropeptide Y and alpha 1b-adrenergic receptors in the regulation of phospholipase C, protein kinase C, and arachidonic acid production. 774 27

Using guanine nucleotides, pertussis toxin, and specific antisera against the COOH-terminals of the alpha-subunits of Gi1/2, Gi3, and G(o), the binding and biological response of the Y2 receptor (Y2R) for peptide YY (PYY) was probed in SMS-KAN neuroblastoma cells. The specific binding of radiolabeled PYY exhibited a single apparent dissociation constant, KD = 76 pM for intact cells and KD = 906 pM for permeabilized cells. However, other data suggested existence of multiple receptor affinity states. A shift in KD and a decrease in apparent number of binding sites (Bmax) was observed in permeabilized cells when incubated with guanine nucleotides. By contrast, in membrane preparations guanine nucleotides induced only a decrease in Bmax. In intact cells, agonist exposure inhibited the intracellular accumulation of forskolin-stimulated cyclic AMP by 80% (IC50 = 420 nM) compared with 94% inhibition (IC50 = 380 nM) in permeabilized cells. In permeabilized cells, preincubation with antisera against alpha i1/2 and alpha i3 blocked the functional response of PYY, with anti-alpha i3 being the most potent; whereas anti-alpha o failed to affect the cyclic AMP levels. These results suggest that permeabilized SMS-KAN cells serve as a good model system for analysis of Y2R binding kinetics and functional response and that the Y2R interacts directly with several different GiS (but not G(o)).
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PMID:Coupling of the human Y2 receptor for neuropeptide Y and peptide YY to guanine nucleotide inhibitory proteins in permeabilized SMS-KAN cells. 783 57

The effects of neuropeptide Y (NPY) on LHRH release from an immortalized cell line were investigated using a flow-through cell culture superfusion system. Immortalized hypothalamic GT1-7 cells were cultured for 72 h and superfused for a total of 180 min. In initial experiments, discrete 5-min pulses of NPY (10(-12)-10(-5) M) were administered to the cells. A clear dose-dependent stimulatory effect on NPY on LHRH release from the cells was observed with a calculated 50% effectiveness concentration of 33 nM. The stimulatory effects of brief NPY exposure were rapid and robust, e.g. reaching and maintaining levels of 173% over baseline for 20 min at the 10(-7) dose. The lowest dose of NPY that showed a significant effect was 10(-10) M; maximal responses were observed at 10(-6) M and reached a plateau thereafter. Control pulses of Dulbecco's modified Eagle's medium (DMEM) and 10(-6) M substance P or arg-vasopressin were also presented to the cells to serve as controls for our pulse protocol, and these challenges produced no significant LHRH responses. The NPY receptor antagonists, PYX1 and PYX2, at 10(-8) M, completely blocked the observed NPY responses in these cells. To assess the NPY receptor subtypes that mediate the NPY effects pharmacologically, GT1-7 cells were challenged with a Y1 receptor agonist, (Leu31Pro34)NPY, a Y2 receptor agonist, NPY(13-36), or peptide YY, at doses 10(-12)-10(-5) M. All four peptides stimulated LHRH release from GT1-7 cells with a rank-ordered potency of NPY = peptide YY > Y1 agonist = Y2 agonist. To examine possible signal transduction mechanism(s) involved in mediating this effect, pertussis toxin, RpcAMPs (cyclic adenosine-3'5'-monophosphothioate Rp diastereomer), Ca(2+)-free DMEM and TMB-8 (3, 4, 5-trimethoxybenzoic acid 8-(diethylamino) octylester) were used to treat the cells before and during superfusion with NPY. Treatment with pertussis toxin, RpcAMPs, and Ca(2+)-free DMEM did not significantly alter NPY-stimulated LHRH release responses to 10(-7) M NPY. However, the addition of 100 microM and 250 microM TMB-8 to Ca(2+)-free DMEM almost completely blocked this NPY effect, as did 10 microM ryanodine. Finally, the locus of action for this NPY effect was examined using tetrodotoxin to reduce action potential propagation in the GT1-7 cells. Tetrodotoxin treatment blocked the LHRH response to NPY by more than 50%.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Neuropeptide Y stimulates luteinizing hormone-releasing hormone release from superfused hypothalamic GT1-7 cells. 792 25

Neuropeptide Y (NPY), a widely distributed peptide with varied activities, inhibits nicotinic receptor-induced [3H]norepinephrine ([3H]NE) secretion from bovine chromaffin cells. The secretion produced by membrane depolarization with high KCl concentrations or veratridine is not inhibited. Fragments of NPY, such as NPY18-36, are potent inhibitors of [3H]NE secretion, whereas [Leu31,Pro34]-NPY and peptide YY have no effect. The response to NPY18-36 is not sensitive to pertussis toxin pretreatment of chromaffin cells. NPY fragments also inhibit nicotinic receptor-induced 45Ca++ influx but not that induced by KCl or veratridine. The rank orders of potency for inhibition of [3H]NE secretion and 45Ca++ influx are the same: NPY18-36 > or = NPY26-36 > NPY13-36. NPY and NPYfree acid are weak inhibitors of secretion but not 45Ca++ influx. Moreover, the IC50s for NPY18-36 inhibition of [3H]NE secretion and 45Ca++ influx are comparable, 1.4 x 10(-6) M and 0.9 x 10(-6) M, respectively. Regression analysis produced a correlation coefficient of 0.9842 (P < .0001). It was concluded that NPY inhibits [3H]NE secretion by a modification of the nicotinic receptor-mediated increase in Ca++ influx. The characterization of the response suggests that the NPY effect is mediated by a previously undefined NPY receptor subtype that was designated Y4.
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PMID:Neuropeptide Y inhibition of nicotinic receptor-mediated chromaffin cell secretion. 796 58

Since the sympathetic nervous system has been shown to exert a trophic influence on vascular smooth muscle cells (SMC), we studied the growth regulating effects of neuropeptide Y (NPY) in cooperation with the sympathetic co-transmitters noradrenaline and adenosine triphosphate (ATP) in human vascular SMC. NPY stimulated DNA synthesis in human SMC grown from subcutaneous arteries and veins (diameter: 0.4 mm) measured by [3H]thymidine incorporation. Also cell number and protein synthesis were stimulated. The effect was mediated through the Y1-receptor and not Y2 or Y3 since the Y1-selective NPY analogue Pro34-NPY and peptide YY stimulated mitogenesis in the same magnitude as NPY while the NPY-fragment NPY13-36 only had minor effects. The effect was blocked by pretreating the cells with pertussis toxin indicating a Gi/o-coupled effect. The other sympathetic co-transmitters, noradrenaline and ATP, also stimulated mitogenesis in the human SMC in a similar magnitude as NPY. When added together NPY and noradrenaline potentiated each other in the mitogenic response. ATP had mainly additive effects. This is the first demonstration that NPY, noradrenaline and ATP stimulates growth in human vascular SMC. This suggests a role of the sympathetic cotransmitters in modulating vascular tone, but also by inducing hypertrophy/hyperplasia with possible clinical consequences.
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PMID:Neuropeptide Y stimulates proliferation of human vascular smooth muscle cells: cooperation with noradrenaline and ATP. 801 10

A negative inotropic effect of neuropeptide Y (NPY) in the mammalian heart has been reported. The mechanism(s) involved in the action of NPY in the heart is still unclear. Since D-myo-inositol 1,4,5-trisphosphate[Ins(1,4,5)P3] is known to be an important second messenger in the regulation of cardiac function, we carried out a study to investigate the status of Ins(1,4,5)P3 levels in response to NPY stimulation in rat cardiomyocytes. We also studied the possible involvement of NPY receptor subtypes in Ins(1,4,5)P3 formation. [Leu31, Pro34]NPY,NPY13-36, NPY and peptide YY (PYY) Induced a concentration-dependent decrease in Ins(1,4,5)P3 levels [measured with an Ins(1,4,5)P3 protein binding assay kit] in rat cardiomyocytes, which was blocked by NPY antagonists NPY18-36 or PYX-2. There is no difference in the inhibitory effect of NPY and PYY on Ins(1,4,5)P3 formation. Furthermore, effects of NPY and its analogues were insensitive to pertussis toxin pretreatment. Two new and more specific Y2 receptor agonists, [Ahx5-24]NPY and [Ahx5-24, gamma-Glu2-epsilon-Lys30]NPY, produced similar effects as NPY13-36 on Ins(1,4,5)P3 formation. These observations indicate that Y1 and Y2 subtypes of NPY receptor in rat cardiomyocytes may be associated with Ins(1,4,5)P3 formation through a pertussis-toxin-insensitive Gq protein. The decreased Ins(1,4,5)P3 formation may be implicated in the negative inotropic effect of NPY in the heart.
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PMID:Inhibitory effect of neuropeptide Y and its analogues on inositol 1,4,5-trisphosphate level in rat cardiomyocytes. 808 28

We examined the effects of neuropeptide Y (NPY) and pancreatic polypeptide on calcium currents (ICa) in acutely dissociated neurons from the adult rat superior cervical ganglion. We found that NPY inhibited the ICa with an estimated IC50 value of 140 nM. This inhibitory effect appeared to be restricted to a subset of cells which were smaller in diameter than the general population. The effect of NPY on the ICa was prevented by pretreatment with pertussis toxin, suggesting the involvement of a GTP-binding protein of the Gi or Go subtype. omega-conotoxin GVIA also occluded the effects of NPY, which suggests that these were directed toward N-type Ca++ channels. The effects of NPY were mimicked by the fragment NPY (13-36) but not by peptide YY, indicating that a receptor distinct from a Y1- or a Y2-like NPY receptor was involved. Finally, we also observed that pancreatic polypeptide inhibited the ICa, suggesting that a pancreatic polypeptide receptor is also present on superior cervical ganglion neurons.
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PMID:Neuropeptide Y and pancreatic polypeptide reduce calcium currents in acutely dissociated neurons from adult rat superior cervical ganglia. 809 66

Receptors for peptide YY (PYY) were identified in the PKSV-PCT renal proximal tubule cell line, derived from transgenic mice (SV40 large T antigen under the control of the rat L-type pyruvate kinase 5'-regulatory sequence). Binding of [125I-Tyr36]monoiodo-PYY ([125I] PYY to cell was specific, saturable, and reversible. The order of potency for peptides for inhibiting [125I]PYY binding was: PYY > neuropeptide Y (NPY) = PYY (13-36) >> pancreatic polypeptide. A single class of receptors was observed with a Kd of 0.37 +/- 0.05 nM and a Bmax of 103 +/- 10 fmol/mg protein. After cross-linking, electrophoresis of covalent [125I]PYY-receptor complexes revealed a single band of M(r) 50,000. PYY receptors were exclusively present at the basolateral membrane surface of polarized cells and were coupled negatively to adenylylcyclase by a pertussis toxin-sensitive G protein. PKSV-PCT cell growth and T antigen expression could be modulated by D-glucose in the medium. PYY receptors were exclusively expressed in proliferative cells cultured in the presence of D-glucose. PYY receptors disappeared in the absence of D-glucose and were expressed again when proliferation was activated by reintroduction of D-glucose. PYY stimulated cell growth (17-26% increase) and promoted [methyl-3H]thymidine incorporation into DNA (64% increase; ED50 = 5 nM PYY) of cells grown in D-glucose-enriched medium. This latter effect of PYY was largely reversed by pretreatment of cells with pertussis toxin. These findings suggest that PYY receptors play a role in epithelial cell growth.
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PMID:Peptide YY receptors in the proximal tubule PKSV-PCT cell line derived from transgenic mice. Relation with cell growth. 839 9

A clone PKSV-PCT Cl.10 referred to as Cl.10 was selected from the PKSV-PCT renal proximal tubule cell line which expressed peptide YY (PYY) receptors (Voisin, T., Bens, M., Cluzeaud, F., Vandewalle, A., and Laburthe, M. (1993) J. Biol. Chem. 268, 20547-20554). In order to identify G(i) protein(s) coupled to PYY receptors, antisense G alpha i protein RNAs were expressed in Cl.10 cells by transfecting the pcDNA3 vector into which were inserted 39 bases of the 5'-noncoding region of G alpha i2 or G alpha i3 used as specific antisense templates. A Cl.10/alpha i2-clone was selected which displayed a drastic decrease (> 90%) of the expression of G alpha i2 without changes of G alpha i3, G alpha s, and G beta subunits (G alpha i1 is not present in Cl.10 cells) as evidenced by Western blots. When compared to untransfected cells, this clone exhibited: (i) an increase in the dissociation constant of PYY receptors (5.3 versus 0.6 nM) identical to that observed in pertussis toxin-treated untransfected cells; (ii) an absence of inhibition of 125I-PYY binding by guanosine 5'-O-(thiotriphosphate) (GTP gamma S); and (iii) the failure of PYY to inhibit cAMP levels and to stimulate [methyl-3H]thymidine incorporation into DNA. A clone was also selected which exhibited a specific decrease (> 80%) of G alpha i3 as compared to untransfected cells. The sensitivity to GTP gamma S and the dissociation constant of PYY receptors as well as PYY-mediated inhibition of cAMP were identical to those observed in untransfected cells. These findings support an exclusive coupling of PYY receptors to G alpha i2.
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PMID:G alpha i RNA antisense expression demonstrates the exclusive coupling of peptide YY receptors to G(i)2 proteins in renal proximal tubule cells. 855 Jun 22

Whole-cell Ca2+ channel currents were recorded in human neuroblastoma (SH-SY5Y) cells, using conventional and perforated-patch techniques. Neuropeptide Y (NPY, 10-1000 nM) caused concentration-dependent inhibition of Ca2+ channel current amplitudes which was pertussis toxin-sensitive, voltage-dependent and associated with slowing of channel activation kinetics, regardless of which recording configuration was used. Inhibition was observed in all cells tested. Similar current inhibitions were observed with NPY (18-36) and peptide YY, but not with [Leu31, Pro34]NPY, indicating that the effects were mediated by Y2 receptors. Pancreatic polypeptide (100 nM) was without effect on Ca2+ channel currents. The effects of NPY were additive with nifedipine (at a supramaximal concentration of 5 microM), suggesting that NPY predominantly inhibits N-type Ca2+ channels present in these cells, and not L-type. The effects of NPY were mimicked by a novel, cyclic analogue of NPY which is 40-fold more selective for Y2 receptors than other commonly used Y2-selective peptides. The cyclic analogue was also more potent than NPY itself, causing maximal current inhibition at approx 300 nM, whereas the response to NPY was not fully saturated at 1 microM. Our results indicate that SH-SY5Y cells represent an excellent model system for studying the coupling of Y2 receptors to N-type channel inhibition. Furthermore, in the absence of selective antagonists for NPY receptor subtypes, the highly selective Y2 agonist cyclic NPY derivative may prove a useful tool for probing the various roles of Y2 receptors in the nervous system.
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PMID:Inhibition of Ca2+ channel currents in human neuroblastoma (SH-SY5Y) cells by neuropeptide Y and a novel cyclic neuropeptide Y analogue. 860 97


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