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

In the present studies, we initiated experiments to identify the signal transduction factors involved in activating phagocytosis, oxidative burst, and degranulation following the binding of IgG-opsonized SE to Fc receptors on the surface of avian heterophils. Peripheral blood heterophils were isolated and exposed to known inhibitors of signal transduction pathways for either 20min (chelerythine, genistein, or verapamil) or 120min (pertussis toxin) at 39 degrees C. The cells were then stimulated for 30min at 39 degrees C with SE opsonized with IgG purified from SE-immune chickens. Phagocytosis, luminol-dependent chemiluminescence (LDCL), and beta-D-glucuronidase release were then evaluated in vitro. The G-protein inhibitor, pertussis toxin, the protein kinase C inhibitor, chelerythine, and the Ca(++) channel blocker, verapamil, markedly reduced phagocytosis in a dose responsive manner. Genistein, a tyrosine kinase inhibitor, had no effect on the phagocytosis of the opsonized SE. Both pertussis toxin (66-98%) and verapamil (47-76%) had marked inhibitory effect on LDCL. Chelerythine (13-25%) and genistein (5-25%) had far less biologically significant effects on LDCL. Neither chelerythine nor genistein had a significant effect on degranulation. Verapamil (2-28%) and pertussis toxin (25-29%) had a moderate inhibitory effect on degranulation stimulated by IgG-opsonized SE. As was found with complement receptor mediated activation of heterophils, the binding of Fc receptors by the IgG-SE complex activated distinct signaling pathways that regulate the functional activities of avian heterophils. Pertussis toxin-sensitive, Ca(++)-dependent, G-proteins and protein kinase C-dependent protein phosphorylation play a major role in the phagocytosis of IgG-opsonized SE. Pertussis toxin-sensitive, Ca(++)-dependent, G-proteins appear to regulate LDCL following Fc receptor binding. The signal transduction inhibitors used in these studies did not affect Fc receptor mediated degranulation by avian heterophils.
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PMID:Signal transduction pathways activated by engaging immunoglobulin Fc receptors on chicken heterophils. 1147 85

The responses of Dictyostelium discoideum amoebae to developing (temporal) and stationary (spatial) gradients of folic acid, cAMP, Ca(2+), and Mg(2+) were studied using the methods of computer-aided image analysis. The results presented demonstrate that the new type of experimental chambers used for the observation of single cells moving within the investigated gradients of chemoattractants permit time lapse recording of single amoebae and determination of the trajectories of moving cells. It was found that, besides folic acid and cAMP (natural chemoattractants for Dictyostelium discoideum amoebae), also extracellular Ca(2+) and Mg(2+) are potent inducers of these cells' chemotaxis, and the amoebae of D. discoideum can respond to various chemoattractants differently. In the positively developing gradients of folic acid, cAMP, Ca(2+), and Mg(2+) oriented locomotion of amoebae directed towards the higher concentration of the tested chemoattractants was observed. However, in the negatively developing (temporal) and stationary linear (spatial) gradients, the univocal chemotaxis of amoebae was recorded only in the case of the Mg(2+) concentration gradient. This demonstrates that amoebae can respond to both developing and stationary gradients, depending upon the nature of the chemoattractant. We also investigated the effects of chosen inhibitors of signalling pathways upon chemotaxis of D. discoideum amoebae in the positively developing (temporal) gradients of tested chemoattractants. Verapamil was found to abolish the chemotaxis of amoebae only in the Ca(2+) gradients. Pertussis toxin suppressed the chemotactic response of cells in the gradients of folic acid and cAMP but did not prevent chemotaxis in those of Ca(2+) and Mg(2+), while quinacrine inhibited chemotaxis in the gradients of folic acid, cAMP, and Ca(2+) but only slightly affected chemotaxis in the Mg(2+) gradient. None of the tested inhibitors causes inhibition of cell random movement, when applied in isotropic solution. Also EDTA and EGTA up to 50 mM concentration did not inhibit locomotion of amoebae in control isotropic solutions.
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PMID:Diverse chemotactic responses of Dictyostelium discoideum amoebae in the developing (temporal) and stationary (spatial) concentration gradients of folic acid, cAMP, Ca(2+) and Mg(2+). 1221 Nov 12

The effects of carbachol and histamine on changes in cytosolic-free calcium ([Ca2+]i) and cell proliferation have been characterized in human ovarian cancer cells (OVCAR-3) and non-tumourigenic Chinese hamster ovary cells (CHO). The muscarinic agonist carbachol increased [Ca2+]i significantly with a rapid biphasic response due to both influx of extracellular calcium and release of calcium from intracellular stores. None of these effects were however seen in CHO cells. The increase in cellular calcium by carbachol was also confirmed by calcium uptake experiments using Ca-45. Carbachol increased Ca-45 uptake by 25% in OVCAR-3 cells but had no effect in CHO cells. Histamine also stimulated calcium mobilization in OVCAR-3 cells but had no effect in CHO cells. The response to histamine was also biphasic although the calcium increase was smaller than with carbachol. Data obtained with selective histamine antagonists showed that the response to histamine was mediated by H-1 histaminergic receptors. Both carbachol and histamine also stimulated cell growth of OVCAR-3 cells but were without effect on CHO cells. The cell proliferating effect of carbachol and of histamine on OVCAR-3 cells as well as the increase in [Ca2+], was totally blocked by atropine and selective H-1 histaminergic receptor antagonist pyrilamine, respectively. Fetal calf serum (FCS) which increased [Ca2+]i in both cell lines also caused a substantial increase in cell growth in the two cell lines. Verapamil partially and TMB-8 totally blocked carbachol stimulated release of calcium from intracellular stores, whereas prenylamine had only a minor inhibitory effect on calcium influx. The effect of verapamil and TMB-8 were most likely resulted from their inhibition of cholinergic receptors rather than a direct inhibition of intracellular calcium release. The carbachol induced effects on calcium transients were also partially inhibited by pertussis toxin and the phorbol ester PMA. Our data suggest that the mitogenic action of carbachol occurs through an increase in [Ca2+]i which promote DNA synthesis and cell growth. These data also indicate the involvement of both a pertussis toxin sensitive and insensitive G-protein as well as protein kinase C in the signal transduction pathway induced by carbachol.
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PMID:Muscarinic acetylcholine and histamine-receptor mediated calcium mobilization and cell-growth in human ovarian-cancer cells. 2156 46


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