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)

We investigated the postnatal developmental changes produced by the muscarinic receptor agonist, carbachol, on the L-type Ca2+ current (ICa(L)) in neonatal (aged 5 to 7 days) and adult (aged 2 to 5 months) rat ventricular cells by using the whole-cell voltage clamp technique. Carbachol inhibited the isoproterenol-stimulated ICa(L). The maximal inhibition was 89.3 +/- 4.8% (n = 5) in neonatal cells and 17.7 +/- 7.7% (n = 9) in adult cells. Carbachol inhibited the forskolin-stimulated ICa(L) to almost same extent as the isoproterenol-stimulated ICa(L). In the cells pretreated with pertussis toxin, carbachol failed to inhibit the isoproterenol-stimulated ICa(L), indicating that carbachol produced its effect via a pertussis toxin-sensitive G-protein pathway. The effects of carbachol in adult cells became more pronounced, increasing from 17.7% to 54.8% (n = 11), with the addition of the synthetic inhibitory G-protein alpha subunit (Gi alpha) (1 microM) to the reaction. Conversely, the alpha subunit of another pertussis toxin-sensitive synthetic G-protein (G(o) alpha, 1 microM) failed to mimic the effect of Gi alpha. These results suggest that, in rat ventricular cells, (1) the action of carbachol on ICa(L) showed a marked decrease during development; (2) the decrease in the effect of carbachol in adult cells is in part due to a decrease in the activity of pertussis toxin-sensitive G protein, especially Gi alpha.
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PMID:Carbachol inhibition of Ca2+ currents in ventricular cells obtained from neonatal and adult rats. 982 94

1. G protein-regulated inward rectifier K+ (GIRK) channels were over-expressed in dissociated rat superior cervical sympathetic (SCG) neurones by co-transfecting green fluorescent protein (GFP)-, GIRK1- and GIRK2-expressing plasmids using the biolistic technique. Membrane currents were subsequently recorded with whole-cell patch electrodes. 2. Co-transfected cells had larger Ba2+-sensitive inwardly rectifying currents and 13 mV more negative resting potentials (in 3 mM [K+]o) than non-transfected cells, or cells transfected with GIRK1 or GIRK2 alone. 3. Carbachol (CCh, 1-30 microM) increased the inwardly rectifying current in 70 % of GIRK1+ GIRK2-transfected cells by 261 +/- 53 % (n = 6, CCh 30 microM) at -120 mV, but had no effect in non-transfected cells or in cells transfected with GIRK1 or GIRK2 alone. Pertussis toxin prevented the effect of carbachol but had no effect on basal currents. 4. The effect of CCh was antagonized by 6 nM tripitramine but not by 100 nM pirenzepine, consistent with activation of endogenous M2 muscarinic acetylcholine receptors. 5. In contrast, inhibition of the voltage-activated Ca2+ current by CCh was antagonized by 100 nM pirenzepine but not by 6 nM tripitramine, indicating that it was mediated by M4 muscarinic acetylcholine receptors. 6. We conclude that endogenous M2 and M4 muscarinic receptors selectively couple to GIRK currents and Ca2+ currents respectively, with negligible cross-talk.
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PMID:Selective activation of heterologously expressed G protein-gated K+ channels by M2 muscarinic receptors in rat sympathetic neurones. 1006 93

Airway smooth muscle hypertrophy contributes to the narrowing of asthmatic airways. Activation of the mitogen-activated protein kinases is an important event in mediating cell proliferation. Because the monomeric G protein p21(ras) is an important intermediate leading to activation of mitogen-activated protein kinases, we questioned which heterotrimeric G protein-coupled receptors were linked to the activation of p21(ras) in cultured human airway smooth muscle and which of the heterotrimeric G protein subunits (alpha or betagamma) transmitted the activation signal. Carbachol and endothelin-1 increased GTP-bound p21(ras) in a pertussis toxin-sensitive manner [ratio of [32P]GTP to ([32P]GTP + [32P]GDP): control, 30 +/- 1.7; 3 min of 1 microM carbachol, 39 +/- 1.1; 3 min of 1 microM endothelin-1, 40 +/- 1.2], whereas histamine, bradykinin, and KCl were without effect. Transfection of an inhibitor of the G protein betagamma-subunit [the carboxy terminus (Gly495-Leu689) of the beta-adrenoceptor kinase 1] failed to inhibit the carbachol-induced activation of p21(ras). These data suggest that Gi- but not Gq-coupled receptors activate p21(ras) in human airway smooth muscle cells, and this effect most likely involves the alpha-subunit.
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PMID:Gialpha but not gqalpha is linked to activation of p21(ras) in human airway smooth muscle cells. 1019 54

Extracellular stimuli induce cytoskeleton reorganization (stress-fiber formation) in cells and Ca2+ sensitization in intact smooth muscle preparations by activating signaling pathways that involve Rho proteins, a subfamily of the Ras superfamily of monomeric G proteins. In airway smooth muscle, the agonists responsible for cytoskeletal reorganization via actin polymerization are poorly understood. Carbachol-, lysophosphatidic acid (LPA)-, and endothelin-1-induced increases in filamentous actin staining are indicative of actin reorganization (filamentous-to-globular actin ratios of 2.4 +/- 0.3 in control cells, 6.7 +/- 0.8 with carbachol, 7.2 +/- 0.8 with LPA, and 7.4 +/- 0.9 with endothelin-1; P < 0.001; n = 14 experiments). Although the effect of all agonists was blocked by C3 exoenzyme (inactivator of Rho), only carbachol was blocked by pertussis toxin. Although carbachol-induced actin reorganization was blocked in cells pretreated with antisense oligonucleotides directed against Galphai-2 alone, LPA- and endothelin-1-induced actin reorganization were only blocked when both Galphai-2 and G(q)alpha were depleted. These data indicate that in human airway smooth muscle cells, carbachol induces actin reorganization via a Galphai-2 pathway, whereas LPA or endothelin-1 induce actin reorganization via either a Galphai-2 or a Gqalpha pathway.
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PMID:Actin reorganization in airway smooth muscle cells involves Gq and Gi-2 activation of Rho. 1048 74

We have characterized the muscarinic ACh receptors (mAChRs) expressed in Madin- Darby canine kidney (MDCK) strain II epithelial cells. Binding studies with the membrane-impermeable antagonist N-[(3)H]methylscopolamine demonstrated that mAChRs are approximately 2.5 times more abundant on the basolateral than on the apical surface. Apical, but not basolateral, mAChRs inhibited forskolin-stimulated adenylyl cyclase activity in response to the agonist carbachol. Neither apical nor basolateral mAChRs exhibited detectable carbachol-stimulated phospholipase C activity. Carbachol application to the apical or the basolateral membrane resulted in a threefold increase in intracellular Ca(2+) concentration, which was completely inhibited by pertussis toxin on the apical side and partially inhibited on the basolateral side. RT-PCR analysis showed that MDCK cells express the M(4) and M(5) receptor mRNAs. These data suggest that M(4) receptors reside on the apical and basolateral membranes of polarized MDCK strain II cells and that the M(5) receptor may reside in the basolateral membrane of a subset of cells.
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PMID:Asymmetric distribution of muscarinic acetylcholine receptors in Madin-Darby canine kidney cells. 1060 Jul 74

The GH3 anterior pituitary cell line has been used as a model to investigate diverse aspects of pituitary cell physiology including Ca2+ homeostasis and secretion. These cells possess muscarinic receptors which, by activating K+ channels and inhibiting Ca2+ channels, should decrease electrical excitability. We measured the effect of carbachol (10 microM) on the frequency of Ca2+ oscillations caused by Ca2+ action potentials in the plasma membrane. Carbachol reduced oscillation frequency by approximately 85% (p < 0.001). This inhibition was reversed by atropine (1 microM), and was prevented by pre-incubation with pertussis toxin (200 ng/ml, 24 h). Since many anterior pituitary cell types secrete acetylcholine, the presence of muscarinic receptors coupled to cell excitability in these cells suggest that ACh could exert a paracrine- or autocrine-like action in GH3 cell cultures. In experiments designed to test this idea, perfusion with 1 microM atropine caused a small but significant increase (p < 0.05) in oscillation frequency when the cells had previously been incubated for 30 min without perfusion. However, this effect was not blocked by either pre-treatment with pertussis toxin or by including atropine during the entire experiment (including the 30-min incubation without perfusion). We conclude that these cells respond to muscarinic agonists by decreasing oscillation frequency but find no evidence for feedback control by endogenous ACh under these conditions.
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PMID:Muscarinic regulation of Ca2+ oscillation frequency in GH3 cells. 1064 26

We have shown that stimulation of beta-adrenergic receptors (beta-AR) by norepinephrine (NE) increases apoptosis in adult rat ventricular myocytes (ARVMs) via a cAMP-dependent mechanism that is antagonized by activation of G(i) protein. The family of mitogen-activated protein kinases (MAPKs) is involved in the regulation of cardiac myocyte growth and apoptosis. Here we show that beta-AR stimulation activates p38 kinase, c-jun N-terminal kinases (JNKs), and extracellular signal-regulated kinase (ERK1/2) in ARVMs. Inhibition of p38 kinase with SB-202190 (10 micrometer) potentiated beta-AR-stimulated apoptosis as measured by flow cytometry and terminal deoxynucleotidyl transferase-mediated nick end labeling (TUNEL) staining. SB-202190 at this concentration specifically blocked beta-AR-stimulated activation of p38 kinase and its downstream substrate MAPK-activated protein kinase-2 (MAPKAPK2). Pertussis toxin, an inhibitor of G(i)/G(o) proteins, blocked the activation of p38 kinase and potentiated beta-AR-stimulated apoptosis. Activation of G(i) protein with the muscarinic receptor agonist carbachol protected against beta-AR-stimulated apoptosis. Carbachol also activated p38 kinase, and the protective effect of carbachol was abolished by SB-202190. PD-98059 (10 micrometer), an inhibitor of ERK1/2 pathway, blocked beta-AR-stimulated activation of ERK1/2 but had no effect on apoptosis. These data suggest that 1) beta-AR stimulation activates p38 kinase, JNKs, and ERK1/2; 2) activation of p38 kinase plays a protective role in beta-AR-stimulated apoptosis in cardiac myocytes; and 3) the protective effects of G(i) are mediated via the activation of p38 kinase.
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PMID:p38 mitogen-activated protein kinase pathway protects adult rat ventricular myocytes against beta -adrenergic receptor-stimulated apoptosis. Evidence for Gi-dependent activation. 1077 Sep 56

Recently, we have isolated a cDNA encoding a muscarinic acetylcholine receptor (mAChR) from Caenorhabditis elegans. To investigate the regulation of phospholipase D (PLD) signaling via a muscarinic receptor, we generated stable transfected Chinese hamster ovary (CHO) cells that overexpress the mAChR of C. elegans (CHO-GAR-3). Carbachol (CCh) induced inositol phosphate formation and a significantly higher Ca(2+) elevation and stimulated PLD activity through the mAChR; this was insensitive to pertussis toxin, but its activity was abolished by the phospholipase C (PLC) inhibitor U73122. Western blot analysis revealed several apparent tyrosine-phosphorylated protein bands after CCh treatment. The CCh-induced PLD activation and tyrosine phosphorylation were significantly reduced by the protein kinase C (PKC) inhibitor calphostin C and down-regulation of PKC and the tyrosine kinase inhibitor genistein. Moreover, the Ca(2+)-calmodulin-dependent protein kinase II (CaM kinase II) inhibitor KN62, in addition to chelation of extracellular or intracellular Ca(2+) by EGTA and BAPTA/AM, abolished CCh-induced PLD activation and protein tyrosine phosphorylation. Taken together, these results suggest that the PLC/PKC-PLD pathway and the CaM kinase II/tyrosine kinase-PLD pathway are involved in the activation of PLD through mAChRs of C. elegans.
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PMID:Phospholipase C, protein kinase C, Ca(2+)/calmodulin-dependent protein kinase II, and tyrosine phosphorylation are involved in carbachol-induced phospholipase D activation in Chinese hamster ovary cells expressing muscarinic acetylcholine receptor of Caenorhabditis elegans. 1085 71

Parasympathetic stimulation of the heart acts through M(2)-muscarinic acetylcholine receptors to regulate ion channel activity and subsequent inotropic status. Although muscarinic signal transduction is mediated via pertussis toxin-sensitive G proteins Galpha(i/o), the specific signal transduction requirements of Galpha(i2) and Galpha(i3) in mediating muscarinic regulated L-type calcium currents (I(Ca, L)), intracellular calcium, and cell contractility remain to be determined. Adult ventricular myocytes were isolated from Galpha(i2)-null mice, Galpha(i3)-null mice, and their wild-type littermates. Cell shortening, intracellular calcium levels, and I(Ca, L) were all measured in response to isoproterenol, a beta-adrenergic receptor agonist, and carbachol, a cholinergic receptor agonist. With isoproterenol stimulation, myocytes from all groups demonstrated a marked increase in calcium currents, correlating with augmented intracellular calcium transient amplitude and cell shortening. Carbachol significantly attenuated the isoproterenol response in wild-type and Galpha(i3)-null cells but had no effect in Galpha(i2)-null cells. This study demonstrates that Galpha(i2), but not Galpha(i3), is required for muscarinic inhibition of the beta-adrenergic response in adult murine ventricular myocytes.
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PMID:Galpha(i2) but not Galpha(i3) is required for muscarinic inhibition of contractility and calcium currents in adult cardiomyocytes. 1107 86

Rat sublingual gland M2 and M3 muscarinic receptors each directly activate exocrine secretion. To investigate the functional role of coreceptor expression, we determined receptor-G protein coupling. Although membrane proteins of 40 and 41 kDa are ADP-ribosylated by pertussis toxin (PTX), and 44 kDa proteins by cholera toxin (CTX), both carbachol-stimulated high-affinity GTPase activity and the GTP-induced shift in agonist binding are insensitive to CTX or PTX. Carbachol enhances photoaffinity labeling ([alpha-(32)P]GTP-azidoaniline) of only 42-kDa proteins that are subsequently tractable to immunoprecipitation by antibodies specific for Galpha(q) or Galpha(11) but not Galpha(12) or Galpha(13). Carbachol-stimulated photoaffinity labeling as well as phosphatidylinositol 4,5-bisphosphate (PIP2) hydrolysis is reduced 55% and 60%, respectively, by M1 receptor blockade with m1-toxin. Galpha(q/11)-specific antibody blocks carbachol-stimulated PIP2 hydrolysis. We also provide estimates of the molar ratios of receptors to Galpha(q) and Galpha(11). Although simultaneous activation of M1 and M3 receptors is required for a maximal response, both receptor subtypes are coupled to Galpha(q) and Galpha(11) to stimulate exocrine secretion via redundant mechanisms.
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PMID:G protein coupling to M1 and M3 muscarinic receptors in sublingual glands. 1124 6


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