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)

Cyanide is generated in neurons and this report examines the two different receptors which mediate cyanide formation in neuronal tissue. An opiate receptor blocked by naloxone increases cyanide production both in rat brain and in rat pheochromocytoma (PC12) cells. A muscarinic receptor in PC12 cells releases cyanide and the effect is blocked by atropine. In rat brain, in vivo, a muscarinic agonist inhibits cyanide generation, possibly by acting on receptor subtypes different from those in PC12 cells. Cyanide generation by a muscarinic agonist in PC12 cells is blocked by pertussis toxin but that caused by an opiate is not. Thus, two different receptors and two different second messenger systems can mediate cyanide generation in PC12 cells. In parallel with the in vivo data, cultured primary rat cortical cells also show decreased cyanide release following muscarinic stimulation. Both blockade of cyanide generation by muscarinic receptor activation and cyanide release by opiate agonists from cortical cells are pertussis toxin insensitive. Similarly, little cyanide generation was seen following cholera toxin treatment. These data indicate that opiate receptors increase and muscarinic receptors decrease cyanide production in rat brain tissue by G-protein independent mechanisms. This work supports the suggestion that the powerful actions of cyanide may be important for neuromodulation in the CNS.
 ...
PMID:Receptor mechanisms mediating cyanide generation in PC12 cells and rat brain. 1509 99

Guanosine 5' triphosphate (GTP), acting synergistically with the nerve growth factor (NGF), enhances the proportion of neurite-bearing cells in cultures of PC12 rat pheochromocytoma cells. We studied the transduction mechanisms activated by GTP in PC12 cells and found that addition of GTP (100 microM) increased intracellular calcium concentration ([Ca(2+)](i)) in cells that were between 60 and 70% confluent. Addition of GTP also enhanced activation of NGF-induced extracellular regulated kinases (ERKs) and induced Ca(2+) mobilization. This mobilization, due to the activation of voltage-sensitive and ryanodine-sensitive calcium channels, as well as pertussis toxin-sensitive purinoceptors, modulates Ca(2+)-activated K(+) channels not involved in activation of ERKs. The results presented here indicate that GTP-triggered [Ca(2+)](i) increase may be a key event in GTP signal transduction, which can modulate activity of ERKs. The physiological importance of the GTP effect lies in its capacity to interact with the NGF-activated pathway to enhance neurite outgrowth from PC12 cells.
 ...
PMID:Cooperation in signal transduction of extracellular guanosine 5' triphosphate and nerve growth factor in neuronal differentiation of PC12 cells. 1546 78

Although feedback inhibition of noradrenaline release by coreleased nucleotides is a well known phenomenon, it remained unclear which P2 receptor subtypes and associated signalling cascades may be involved. In the rat pheochromocytoma cell line PC12, 2-methylthio-ADP reduced noradrenaline release triggered by K+ depolarization more potently than ADP and ATP, whereas UDP or UTP failed to do so. The inhibition by ADP was abolished by pertussis toxin and antagonized by reactive blue 2, 2-methylthio-AMP, and AR-C69931MX, but not by suramin. AR-C69931MX acted as a competitive antagonist with an apparent affinity of 2 nm, but did not alter noradrenaline release, when PC12 cells were continuously superfused. However, when the superfusion was halted during K+ depolarization, release was significantly reduced and this inhibition was attenuated by AR-C69931MX, thus revealing ongoing autoinhibition. Rises in cellular cyclic AMP did not alter depolarization-evoked release nor its reduction by ADP, even though the nucleotide did inhibit cyclic AMP accumulation. ADP and the direct Ca2+ channel blocker Cd2+ inhibited voltage-activated Ca2+ currents, but not ATP-induced currents, and both agents reduced K+-evoked, but not ATP-evoked, release. Hence, if voltage-gated Ca2+ channels do not contribute to stimulation-evoked release, ADP fails to exert its inhibitory action. In primary cultures of rat sympathetic neurons, ADP also reduced Ca2+ currents and K+-evoked noradrenaline release, and AR-C69931MX acted again as competitive antagonist with an apparent affinity of 3 nm. These results show that P2Y12 receptors mediate an autoinhibition of transmitter release from PC12 cells and sympathetic neurons through an inhibition of voltage-gated Ca2+ channels.
 ...
PMID:Autoinhibition of transmitter release from PC12 cells and sympathetic neurons through a P2Y receptor-mediated inhibition of voltage-gated Ca2+ channels. 1557 46

In Galpha(z)-deficient mice, survival of sympathetic neurons is significantly attenuated in the presence of pertussis toxin (PTX). This suggests that G(i/o) proteins may have distinct roles in neuronal survival. Here, we investigated the possible involvement of G(i/o) proteins in nerve growth factor (NGF)-induced pro-survival phosphatidylinositol-3-kinase (PI3K)/Akt signaling in rat pheochromocytoma PC12 cells. Treatment of PC12 cells with NGF increased the Akt phosphorylation level in a time- and dose-dependent manner. The NGF-dependent Akt activation was partially attenuated by PTX or overexpression of regulators of G protein signaling Z1 (RGSZ1) and Galpha-interacting protein (GAIP)), indicating the participation of G(i/o) proteins. In contrast, epidermal growth factor (EGF)-mediated Akt phosphorylation was unaffected by PTX or RGSZ1 and GAIP. Expression of PTX-resistant mutants of Galpha(i1), Galpha(i3), Galpha(oA), and Galpha(oB), but not Galpha(i2), abolished the inhibitory effect of PTX on NGF-induced Akt activation. The use of transducin as a Gbetagamma scavenger further revealed that Gbetagamma subunits rather than Galpha(i/o) acted as the signal transducer. The activation profiles of Akt-regulated downstream effectors such as Bad, IKK, and nuclear factor-kappaB (NFkappaB) were also examined. NGF-stimulated phosphorylation of Bad and IKK and transcriptional activity of NFkappaB were indeed sensitive to treatments with PTX. This is the first study that demonstrates the involvement of G(i/o) proteins in NGF-induced Akt signaling.
 ...
PMID:Pertussis toxin-sensitive Gi/o proteins are involved in nerve growth factor-induced pro-survival Akt signaling cascade in PC12 cells. 1576 30

Purkinje cell protein-2 (Pcp2 or L7) is highly expressed in cerebellar Purkinje cells and retinal bipolar neurons and interacts with the Galpha(i/o) family of G-proteins. Although the expression pattern of Pcp2 in the developing central nervous system suggests a role in differentiation, its function remains unknown. We established Tet-off inducible expression of Pcp2 in PC12 cells (rat pheochromocytoma cells) to determine whether Pcp2 regulates neuronal differentiation. Utilizing a polyclonal antibody, Pcp2 was localized in the cell body and throughout neurites of differentiated PC12 cells, similar to its localization in cerebellar Purkinje cells. Pcp2 expression in PC12 cells stimulated process formation (5-fold) and NGF (nerve growth factor)-stimulated neurite length (2-fold). Under basal conditions, Pcp2-PC12 cells demonstrated a 5-fold increase in Ras activation relative to non-induced PC12 cells and there was no change in extracellular-signal-regulated kinase 1/2 activity with Pcp2 expression. However, Pcp2 induction led to a >3-fold increase in basal p38 MAPK (mitogen-activated protein kinase) activity and the addition of NGF significantly stimulated both Ras and p38 MAPK in Pcp2-PC12 cells relative to the controls. Pretreatment of Pcp2-PC12 cells with the p38-specific inhibitor SB203580 blocked both the increased neurite formation and NGF-stimulated neurite growth. Pertussis toxin treatment had no effect on neurite growth in control cells, but completely blocked Pcp2-mediated increased neurite growth. Transient transfection of the beta-adrenergic receptor kinase C-terminus to prevent signalling through Gbetagamma in Pcp2-PC12 cells also inhibited the Pcp2-induced phenotype and reduced the Pcp2-stimulated Ras activation. Taken together, these findings demonstrate that Pcp2 induces differentiation in PC12 cells, in part through Gbetagamma-mediated Ras and p38 MAPK activation and suggest the potential for similar signalling mechanisms in Purkinje cells.
 ...
PMID:Purkinje cell protein-2 (Pcp2) stimulates differentiation in PC12 cells by Gbetagamma-mediated activation of Ras and p38 MAPK. 1594 14

We found that Grifola frondosa extracts induced the activation of mitogen-activated protein kinase (MAPK) in cultured PC12 cells, a line of rat pheochromocytoma cells. The active substance was isolated by a few chromatographic steps, including high-performance liquid chromatography, and was identified to be lysophosphatidylethanolamine (LPE) from various structural analyses. LPE from G. frondosa (GLPE) was confirmed to induce the activation of MAPK of cultured PC12 cells and was found to suppress cell condensation and DNA ladder generation evoked by serum deprivation, suggesting that the GLPE had antiapoptotic effects. Moreover, GLPE caused morphological changes in and upregulation of neurofilament M expression of PC12 cells, demonstrating that the GLPE could induce neuronal differentiation of these cells. The activation of MAPK by GLPE was suppressed by AG1478, an antagonist of epidermal growth factor receptor (EGFR), and by U0126, an inhibitor of MAPK kinase (MEK1/2), but not by K252a, an inhibitor of TrkA, or by pertussis toxin. These results demonstrate that GLPE induced the MAPK cascade [EGFR-MEK1/2-extracellular signal-regulated protein kinases (ERK1/2)] of PC12 cells, the activation of which induced neuronal differentiation and suppressed serum deprivation-induced apoptosis. This study has clarified for the first time the involvement of the MAPK signal cascade in LPE actions.
 ...
PMID:Lysophosphatidylethanolamine in Grifola frondosa as a neurotrophic activator via activation of MAPK. 1661 93

Endocrine-disrupting compounds (EDCs) may interfere with neuronal development due to high levels of accumulation in biological tissue and potentially aberrant steroid signaling. Treatment of dissociated embryonic Xenopus spinal cord neurons with the EDC, nonylphenol (NP), did not alter cell survival or neurite outgrowth but inhibited neurotrophin-induced neurite outgrowth, effects that were recapitulated by treatment with comparable concentrations of 17 beta-estradiol (E2) and beta-estradiol 6-(O-carboxy-methyl)oxime: BSA (E2-BSA), but not a synthetic androgen. Effects of NP were not inhibited by the nuclear estrogen receptor antagonist, ICI 182,780, but were inhibited by the G protein antagonist, pertussis toxin. Nerve growth factor (NGF)-induced neurite outgrowth in Xenopus neurons was shown to require MAPK signaling. NP did not affect TrkA expression, MAPK signaling, or phosphatidylinositol 3' kinase-Akt-glycogen synthase kinase 3 beta (PI3K-Akt-GSK3 beta) signaling in Xenopus. The ability of NP to inhibit NGF-induced neurite outgrowth without altering survival was recapitulated in the rat pheochromocytoma (PC12) cell line. As with Xenopus neurons, the inhibitory actions of NP in PC12 cells were not antagonized by ICI 182,780 and did not involve alterations in signaling along either the MAPK or PI3K-Akt-GSK3 beta pathways. NP did significantly inhibit the ability of NGF to increase protein kinase A activity in this cell line. These data have important implications with respect to potentially deleterious effects of NP exposure during early neural development and highlight the fact that bioaccumulation of EDCs, such as NP, may elicit very disparate effects along divergent signaling pathways than those that arise from the actions of physiological levels of endogenous estrogens.
 ...
PMID:The endocrine-disrupting compound, nonylphenol, inhibits neurotrophin-dependent neurite outgrowth. 1677 73

We found that ebselen [2-phenyl-1,2-benzisoselenazol-3(2H)-one] caused phosphorylation of mitogen-activated protein kinase (MAPK), followed by expression of neurofilament-M, a neuron-specific protein, in cultured PC12 rat pheochromocytoma cells. The ebselen-induced MAPK activation was suppressed by U0126, an inhibitor of MAPK kinase (MEK1/2), but not by K252a, a selective inhibitor of Trk family tyrosine kinases; AG1478, an antagonist of epidermal growth factor receptor (EGFR); pertussis toxin, an inhibitor of Gi/o; or GP antagonist-2A, an inhibitor of Gq. Furthermore, we observed that N-acetyl-L-cysteine, an inhibitor of tyrosine kinases, suppressed ebselen-induced MAPK activation and buthionine sulfoximine, an activator of protein tyrosine phosphatases, enhanced the effect, indicating that ebselen activated MEK1/2 through one or more tyrosine kinases. Based on these results, we propose that ebselen stimulated intracellular tyrosine kinase activity, thus activating a MAPK cascade (tyrosine kinase-MEK1/2-ERK1/2) in PC12 cells and that this activation resulted in their neuronal differentiation.
 ...
PMID:Ebselen, a redox regulator containing a selenium atom, induces neurofilament M expression in cultured rat pheochromocytoma PC12 cells via activation of mitogen-activated protein kinase. 1791 45

Human immunodeficiency virus (HIV)-1 Tat is a multifunctional protein involved in viral replication, inflammation and apoptosis. Tat activates phospholipase C-beta (PLC-beta), presumably via a pertussis toxin (PTX) sensitive G(i) protein, which is critical for neuronal apoptosis. In this study, we show that Tat-mediated intracellular Ca(2+) release in rat pheochromocytoma (PC-12) cells and rat primary cortical neuronal cultures was abrogated by pretreatment with either pertussis toxin and/or its B-oligomer subunit (PTX-B), devoid of ADP ribosyltransferase activity. PTX-B pretreatment also inhibited intracellular Ca(2+) release by bradykinin and 2,4,6-trimethyl-N-(m-3-trifluoromethylphenyl) benzenesulfonamide (m-3M3FBS), a director activator of phospholipase C. Activation of protein kinase C (PKC) by phorbol 12,13-dibutyrate (PdBu) mimicked the PTX-B-mediated inhibition of m-3M3FBS-stimulated intracellular Ca(2+) increase, while inhibition of PKC by bisindolylmaleimide I hydrochloride (BIM) reversed the inhibitory action of PTX-B. Functionally, PTX-B reduced Tat-induced Bax and caspase-3 proteins and reduced cell apoptosis. We conclude that PTX inhibition of Tat-mediated intracellular Ca(2+) release is independent of ADP ribosylation of the G(i) protein via the A protomer, but mediated by the B-oligomer. Furthermore, PTX-B suppresses HIV-1 Tat-mediated apoptosis by reducing its activation of PLC-beta through a PKC activation pathway.
 ...
PMID:Pertussis toxin B-oligomer suppresses human immunodeficiency virus-1 Tat-induced neuronal apoptosis through feedback inhibition of phospholipase C-beta by protein kinase C. 1809 42

Extracellular signal-regulated kinases (ERKs) play important physiological roles in proliferation, differentiation and gene expression. ERK5 is twice the size of ERK1/2, the amino-terminal half contains the kinase domain that shares the homology with ERK1/2 and TEY activation motif, whereas the carboxy-terminal half is unique. In this study, we examined the cross-talk mechanism between G-protein-coupled receptors (GPCRs) and receptor tyrosine kinases, focusing on ERK1/2 and 5. The pretreatment of rat pheochromocytoma cells (PC12) with pertussis toxin (PTX) specifically enhanced epidermal growth factor (EGF)-induced ERK5 phosphorylation. In addition, lysophosphatidic acid (LPA) attenuated the EGF-induced ERK5 phosphorylation in LPA(1) receptor- and G(i/o)-dependent manners. On the other hand, LPA alone activated ERK1/2 via Gbetagamma subunits and Ras and potentiated EGF-induced ERK1/2 phosphorylation at late time points. These results suggest G(i/o) negatively regulates ERK5, while it positively regulates ERK1/2. LPA did not affect cAMP levels after EGF treatment, and the reagents promoting cAMP production such as forskolin and cholera toxin also attenuated the EGF-induced ERK5 phosphorylation, indicating that the inhibitory effect of LPA on ERK5 inhibition via G(i/o) is not due to inhibition of adenylyl cyclase by Galpha(i/o). However, the inhibitory effect of LPA on ERK5 was abolished in PC12 cells stably overexpressing C-terminus of GPCR kinase2 (GRK2), and overexpression of Gbeta(1) and gamma(2) subunits also suppressed ERK5 phosphorylation by EGF. In response to LPA, Gbetagamma subunits interacted with EGF receptor in a time-dependent manner. These results strongly suggest that LPA negatively regulates the EGF-induced ERK5 phosphorylation through Gbetagamma subunits.
 ...
PMID:Betagamma subunits of G(i/o) suppress EGF-induced ERK5 phosphorylation, whereas ERK1/2 phosphorylation is enhanced. 1840 64


<< Previous 1 2 3 4 5 6