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)

Addition of the neuropeptide galanin to small cell lung cancer (SCLC) cells loaded with the fluorescent Ca2+ indicator fura-2-tetraacetoxymethylester causes a rapid and transient increase in the intracellular concentration of Ca2+ ([Ca2+]i) followed by homologous desensitization. Galanin increased [Ca2+]i in a concentration-dependent fashion with half-maximum effect (EC50) at 20-22 nM in H69 and H510 SCLC cells. Galanin mobilized Ca2+ from intracellular stores since its effects on [Ca2+]i were not blocked by chelation of extracellular Ca2+. Pretreatment with pertussis toxin (200 ng/ml for 4 h) did not prevent galanin-induced Ca2+ mobilization. In contrast, direct activation of protein kinase C with phorbol esters attenuated the Ca2+ response induced by galanin. The effects of galanin could be dissociated from changes in membrane potential: galanin did not increase membrane potential in SCLC cells loaded with bis(1,3-diethyltiobarbiturate)-trimethineoxonol and induced Ca2+ mobilization in depolarized SCLC cells, i.e., in cells suspended in a solution containing 145 mM K+ instead of Na+. Galanin also caused an increase in the formation of inositol phosphates in a time- and dose-dependent manner (EC50 10 nM). A rapid increase in the inositol trisphosphate fraction was followed by a slower increase in the inositol monophosphate fraction. Galanin stimulated clonal growth of both H69 and H510 cells in semisolid (agarose-containing) medium. This growth-promoting effect was sharply dependent on galanin concentration (EC50 20 nM) and markedly inhibited by [Arg6,D-Trp7,9,MePhe8]substance P, a recently identified broad spectrum neuropeptide antagonist. The results show for the first time that galanin receptors are coupled to inositol phosphate and [Ca2+]i responses in SCLC cells and, in particular, that this neuropeptide can act as a direct growth factor for these human cancer cells.
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PMID:Galanin stimulates Ca2+ mobilization, inositol phosphate accumulation, and clonal growth in small cell lung cancer cells. 170 78

Carbachol induces a novel tetrodotoxin-resistant Na+ current in guinea pig ventricular myocytes bathed in Tyrode's solution with 20 mM Cs+. This action of carbachol, which initiates a series of reactions that culminates in a catecholamine-independent positive inotropic effect, occurs through muscarinic rather than nicotinic cholinoceptive sites. The concentrations of muscarinic antagonists required to suppress the carbachol-induced current by 50% were 2.1 nM, 270 nM, and 1700 nM for atropine, AF-DX 116, and pirenzepine, respectively. These results indicate that an M2-selective antagonist, AF-DX 116, is more potent than an M1-selective antagonist, pirenzepine, as an inhibitor. The M1-selective agonist McN-A-343 did not induce an inward current and blocked that caused by carbachol, in a rapid and reversible manner. This finding is also consistent with the conclusion that the muscarinic receptor involved in the regulation of myocardial Na+ channels by carbachol cannot be distinguished from the M2 subtype of such receptors. Treatment with pertussis toxin did not affect the ability of carbachol to induce an inward current in ventricular myocytes and reversed the current activated by carbachol in atrial cells from outward to inward. The electrophysiological and pharmacological nature of the carbachol-induced current in ventricular myocytes is very similar to that of the acetylcholine-induced current in Xenopus oocytes transfected with porcine M2, but not M1, muscarinic receptors. In both preparations, Na+ is the dominant charge carrier, intracellular Ca2+ is not involved in opening the Na+ channel, and an M2 receptor is involved.
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PMID:Carbachol activates a novel sodium current in isolated guinea pig ventricular myocytes via M2 muscarinic receptors. 170 71

As a target site for angiotensin II (A-II), renal proximal tubule is unique in that it may be equipped with a local A-II generating system and that both basolateral and apical membranes may be accessible for A-II's action. We have recently conducted studies to examine these possibilities. With in vitro cultured proximal tubular cells, we have demonstrated de novo synthesis of angiotensinogen and renin. With isolated renal brush border membrane (BBM), we have confirmed the presence of A-II receptors and found that A-II directly stimulated BBM Na(+)-H+ exchange. In search of the signal transduction mechanism, we have found that A-II also activated BBM phospholipase A2 (PLA) and that BBM contained a pertussis toxin-sensitive guanine nucleotide binding protein (G-protein) which mediates the effects of A-II. Further studies showed that prevention of PLA activation abolished A-II's effect on Na(+)-H+ exchange, and that activation of PLA by mellitin and addition of arachidonic acid similarly enhanced Na(+)-H+ exchange activity, suggesting that PLA activation may mediate the stimulatory effect of A-II on Na(+)-H+ exchange. These results thus indicate that a local signal transduction mechanism involving G-protein mediated PLA activation exists in renal BBM which mediates A-II's effect on Na(+)-H+ exchange. Taken together, we propose that, independent of A-II in the circulation, local luminal A-II may serve as an important regulatory system on sodium transport in renal proximal tubule.
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PMID:Angiotensin II and proximal tubule sodium transport. 170 7

1. Multiple distinct affinity states or sites of substance P (SP) receptors exist in freshly-prepared rat brain membranes. 2. Substance P receptors may couple with islet-activating protein (pertussis toxin) sensitive GTP-binding protein(s). 3. Substance P receptors may be regulated Mg2+ and Na+ in an opposite manner. 4. Some important factor(s), in addition to GTP-binding protein, appear to be involved in SP binding activity. 5. An apparent molecular weight of the SP binding site is approximately 46,000 Da.
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PMID:Substance P receptors in mammalian central nervous system. 170 76

Treatment of BC3H1 myocytes or 3T3-L1 fibroblasts with fluoroaluminate (AlF4-), a direct activator of G proteins, increased the tyrosine phosphorylation of a 42-kDa cytosolic protein. AlF4- induced a parallel increase in protein kinase activity toward myelin basic protein (MBP) in partially purified cell extracts. To test whether AlF4- was activating the 42-kDa MAP (mitogen-activated protein) kinase, extracts from AlF4--treated cells were taken through the chromatographic steps routinely used to purify MAP kinase from growth factor-stimulated cells. Following phenyl-Superose chromatography, a peak of MBP kinase activity eluted at a position characteristic of MAP kinase. Immunoblotting of the active fractions with anti-phosphotyrosine antibodies revealed a single reactive protein band of Mr 42,000. Stimulation of MAP kinase by AlF4- was rapid, peaking within 15 min and persisting for at least 1 h. In contrast, the activation of MAP kinase by insulin was transient, characteristic of its activation by growth factors in other cell types. Although concentrations of sodium fluoride greater than 1 mM also activated MAP kinase, this effect was shown to be dependent upon the simultaneous presence of aluminum ions in the medium. Activation of MAP kinase by AlF4- was not affected by either cellular depletion of protein kinase C or pretreatment of cells with pertussis toxin. Potential sites of action of AlF4- are discussed. These findings suggest that activation of a G protein(s) in intact cells can initiate events that result in tyrosine phosphorylation and activation of MAP kinase.
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PMID:Activation of mitogen-activated protein kinase in BC3H1 myocytes by fluoroaluminate. 170 25

Spleen cells from mice immunized with a Bordetella pertussis N-lauroyl sarcosine membrane extract (SME) were used to generate hybridoma cells lines producing monoclonal antibodies (mAbs). Seven mAbs were shown to be specific to B. pertussis lipo-oligosaccharide (LOS) by immunoblotting of SME or purified LOS following SDS-PAGE. All mAbs reacted with the B. pertussis Tohama I strain of the LOS AB phenotype, and did not react with the atypical variant strain 134 of the LOS B phenotype. The immune reactivity of the mAbs was retained after treatment of SME with proteinase K and was lost after sodium periodate treatment. No cross-reactivity was observed with the mAbs when tested against B. parapertussis and other Gram-negative bacteria. However, all mAbs reacted with B. bronchiseptica. Binding assays with live B. pertussis cells demonstrated that mAbs strongly reacted with cell surface exposed antigenic determinants. High bacterial cell lytic capability was observed for five of these mAbs. Concentrations between 0.22 and 2.2 micrograms mAb ml-1 (0.1 and 1 microgram per 450 microliter assay) purified by protein A were required to kill at least 50% of the bacteria. Competition immunoassays with biotinylated antibodies showed that the bacteriolytic and non-bacteriolytic mAbs were directed to different epitopes of the B. pertussis LOS A.
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PMID:Characterization and comparative bactericidal activity of monoclonal antibodies to Bordetella pertussis lipo-oligosaccharide A. 171 58

Substance P (SP) stimulates polyphosphoinositide breakdown in the rat anterior pituitary through an NK-1 receptor. In the present study we present evidence that the coupling between the SP-NK1 receptor complex and polyphosphoinositide-specific phospholipase C (PI-PLC) in rat anterior pituitary membranes may involve a mechanism consistent with a GTP-binding protein. The formation of inositol phosphates from [3H]myo-inositol-labelled anterior pituitary membranes induced by SP was potentiated by GTP and non-hydrolysable guanine nucleotides. The stimulatory effects of SP alone and SP plus GTP could be blocked by addition of GDP-beta-S (guanosine 5-O-(thiodiphosphate] in excess. Basal and SP plus guanine nucleotide-induced inositol phosphate formation were stimulated by fluoride, whereas the effect of SP alone was inhibited. Pretreatment of anterior pituitary membranes with sodium deoxycholate attenuated the inositol phosphate response elicited by GTP and GTP-gamma-S, whereas basal and SP-stimulated inositol phosphate production showed a peak at 1 mg sodium deoxycholate/ml. SP, fluoride and guanine nucleotide stimulatory effects on hydrolysis of polyphosphoinositide (PPI) were unaffected by pretreatment of anterior pituitary cells with cholera or pertussis toxin for 12h. Treatment of anterior pituitary membranes with cholera and pertussis toxin yielded [32P]ADP-ribosylation of two proteins with molecular masses of 45 and 41 kDa respectively. We conclude that SP coupling to PI-PLC through the NK1 receptor in the rat anterior pituitary involves a GTP-binding mechanism distinct from the G-proteins associated with adenylate cyclase, Gs and Gi.
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PMID:Substance P stimulation of polyphosphoinositide hydrolysis in rat anterior pituitary membranes involves a GTP-dependent mechanism. 171 80

1. Intracellular and whole-cell recordings were made from primary cultures of rat intermediate pituitary cells; beta-endorphin secretion was also measured by radioimmunoassay. The effects of dopamine receptor activation on hormone secretion, calcium currents and resting potassium conductance were compared. 2. Spontaneous sodium-dependent action potentials occurred in 82% of cells recorded with intracellular microelectrodes and 64% of cells recorded with whole-cell patch electrodes; the same proportion of cells showed spontaneous calcium-dependent depolarizations in the presence of tetrodotoxin. 3. Calcium currents recorded from holding potentials of -90 or -70 mV showed transient and sustained components, both of which activated at -40 mV and had similar current-voltage relations. Bay K 8644 (1 microM) increased both components by about 130% while nifedipine (1-10 microM) decreased them by a maximum of 30%. Nickel (500 microM) inhibited transient and sustained components by 68 and 50%; cadmium (100 microM) abolished the current. omega-Conotoxin (1 microM) reversibly inhibited the transient component by 26%. 4. The dopamine D2 receptor agonist, quinpirole (0.1-10 microM) inhibited transient and sustained components in all cells by a maximum of 40 and 25% respectively. Quinpirole did not alter the time course of the current. 5. Quinpirole (1-100 nM) hyperpolarized 90% of cells from which intracellular recordings were made and 55% of cells recorded from with whole-cell patch pipettes. Maximum hyperpolarization of 16 +/- 4 mV from a resting potential of -44 +/- 5 mV was observed with 100 nM-quinpirole; concentration producing half-maximal effect was 3 nM. The hyperpolarization resulted from an increase in potassium conductance. 6. Quinpirole (1-100 nM) decreased basal beta-endorphin secretion by 55% and abolished secretion stimulated by Bay K 8644 or isoprenaline; concentrations producing half-maximal inhibitions were 5-10 nM. Tetrodotoxin (1 microM), nifedipine (1 microM), nickel (500 microM) and cadmium (100 microM) did not alter basal or stimulated secretion although higher concentrations of cadmium did inhibit stimulated hormone release. 7. Pertussis toxin pre-treatment prevented all actions of quinpirole. 8. Thus, concentrations of quinpirole that abolished stimulated hormone secretion did not alter calcium currents; conversely, concentrations of calcium channel blockers that partially or completely inhibited calcium currents did not alter basal or stimulated secretion. These results may indicate that calcium influx through the voltage-dependent calcium channels measured in these experiments does not contribute significantly to hormone release from melanotrophs.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Dopamine actions on calcium currents, potassium currents and hormone release in rat melanotrophs. 171 75

Thyrotropin-releasing hormone (TRH) stimulates pituitary secretion by steps involving a cytosolic Ca2+ rise. We examined various pathways of Ca2+ elevation in pituitary GH3 cells. By using the patch clamp technique in the whole-cell configuration and Ba2+ as divalent charge carrier through Ca2+ channels, TRH (1 microM) reversibly reduced the current by about 55%. This hormonal effect was prevented by infusing guanine 5'-[beta-thio]diphosphate (GDP[beta S]) intracellularly but not by pretreating the cell with pertussis toxin (PT). Since PT-insensitive guanine nucleotide-binding regulatory (G) proteins are known to mediate a hormone-stimulated inositol trisphosphate-mediated Ca2+ release from intracellular stores, we assume that the inhibitory effect of TRH on Ba2+ currents through Ca2+ channels is caused by the increased intracellular Ca2+. To prevent a Ca(2+)-release-dependent inhibition of Ca2+ channels, we preincubated GH3 cells in a medium free of divalent charge carriers and measured the Na+ current through Ca2+ channels. When fura-2 was used as indicator for the cytosolic Ca2+, TRH induced a release from intracellular stores only once and had no effect on the intracellular Ca2+ concentration during further applications. In line with this observation, TRH initially reduced the Na+ current through Ca2+ channels but stimulated it during subsequent applications. The stimulation was sensitive to GDP[beta S] and was abolished by pretreatment with PT, suggesting that the stimulatory action of TRH is mediated by a G protein different from the one that functionally couples the receptor to phosphatidylinositol 4,5-bisphosphate hydrolysis. In conclusion, the present data suggest that TRH increases the intracellular Ca2+ concentration by two interacting pathways, that release from intracellular stores causes a secondary blockage of Ca2+ channels, and that, especially with empty intracellular Ca2+ stores, Ca2+ channels are stimulated by a PT-sensitive G protein.
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PMID:Thyrotropin-releasing hormone induces opposite effects on Ca2+ channel currents in pituitary cells by two pathways. 171 53

The heterohybridoma cell line HBp2 secreting human monoclonal antibody (hMAb) directed against Bordetella pertussis was generated by fusing SP2/HPT heteromyeloma cells with human spleen lymphocytes, after in vitro stimulation for 6 days. The hybridoma was maintained in culture for more than 1 year with continuous antibody secretion. The hMAb HBp2, an IgM, reacted with untreated and proteinase K-treated B. pertussis outer membrane antigens, whereas the reactivity was lost when the antigen was treated with sodium periodate. Human MAb HBp2 was shown to be specific to B. pertussis LOS by immunoblotting of whole cell extracts after SDS-PAGE. In a dot enzyme immunoassay, HBp2 reacted with all B. pertussis strains and clinical isolates tested except for four atypical variant strains of the LOS B phenotype. Human MAb HBp2 also reacted with a clinical isolate of B. bronchiseptica. No reaction was observed against B. parapertussis and other gram-negative species. Together these studies suggested that HBp2 is reactive with carbohydrate epitopes present on the LOS A. Binding assays with live bacteria demonstrated that hMAb HBp2 reacted with cell surface exposed epitopes on B. pertussis but the antibody did not bind significantly to the surface on intact B. bronchiseptica cells. When examined for bactericidal activity in the presence of complement, hMAb HBp2 showed high lytic capability against B. pertussis while no killing was obtained against B. bronchiseptica. These experiments established that LOS A is a target for human bactericidal antibodies. This antigen merits further investigation as a potentially important component in human immunity to B. pertussis infection.
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PMID:Biological activity of a human monoclonal antibody to Bordetella pertussis lipooligosaccharide. 172 52


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