scholarly journals Non-genomic effects of progesterone on Rho kinase II in rat gastric smooth muscle cells

2013 ◽  
Vol 49 (0) ◽  
pp. 55-62 ◽  
Author(s):  
Othman Al-Shboul ◽  
Ayman Mustafa ◽  
Farah Al-hashimi
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Rho Kinase ◽  
Muscle Cells ◽  
Gastric Smooth Muscle ◽  
Genomic Effects

Distinctive G protein-dependent signaling in smooth muscle by sphingosine 1-phosphate receptors S1P1and S1P2

2004 ◽  
Vol 286 (5) ◽  
pp. C1130-C1138 ◽  
Author(s):  
Huiping Zhou ◽  
Karnam S. Murthy
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Kinase Inhibitor ◽  
Rho Kinase ◽  
Muscle Cells ◽  
Rt Pcr ◽  
Sustained Contraction ◽  
Gastric Smooth Muscle ◽  
Rho Kinase Inhibitor ◽  
Sphingosine 1 Phosphate

We examined expression of sphingosine 1-phosphate (S1P) receptors and sphingosine kinase (SPK) in gastric smooth muscle cells and characterized signaling pathways mediating S1P-induced 20-kDa myosin light chain (MLC20) phosphorylation and contraction. RT-PCR demonstrated expression of SPK1 and SPK2 and S1P1and S1P2receptors. S1P activated Gq, G13, and all Giisoforms and stimulated PLC-β1, PLC-β3, and Rho kinase activities. PLC-β activity was partially inhibited by pertussis toxin (PTX), Gβ or Gαqantibody, PLC-β1 or PLC-β3 antibody, and by expression of Gαqor Gαiminigene, and was abolished by a combination of antibodies or minigenes. S1P-stimulated Rho kinase activity was partially inhibited by expression of Gα13or Gαqminigene and abolished by expression of both. S1P stimulated Ca2+release that was inhibited by U-73122 and heparin and induced concentration-dependent contraction of smooth muscle cells (EC501 nM). Initial contraction and MLC20phosphorylation were abolished by U-73122 and MLC kinase (MLCK) inhibitor ML-9. Initial contraction was also partially inhibited by PTX and Gαqor Gβ antibody and abolished by a combination of both antibodies. In contrast, sustained contraction and MLC20phosphorylation were partially inhibited by a PKC or Rho kinase inhibitor (bisindolylmaleimide and Y-27632) and abolished by a combination of both inhibitors but not affected by U-73122 or ML-9. These results indicate that S1P induces 1) initial contraction mediated by S1P2and S1P1involving concurrent activation of PLC-β1 and PLC-β3 via Gαqand Gβγi, respectively, resulting in inositol 1,4,5-trisphosphate-dependent Ca2+release and MLCK-mediated MLC20phosphorylation, and 2) sustained contraction exclusively mediated by S1P2involving activation of RhoA via Gαqand Gα13, resulting in Rho kinase- and PKC-dependent MLC20phosphorylation.

scholarly journals Inhibition of RhoA-dependent pathway and contraction by endogenous hydrogen sulfide in rabbit gastric smooth muscle cells

2015 ◽  
Vol 308 (6) ◽  
pp. C485-C495 ◽  
Author(s):  
Ancy D. Nalli ◽  
Senthilkumar Rajagopal ◽  
Sunila Mahavadi ◽  
John R. Grider ◽  
Karnam S. Murthy
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Muscle Contraction ◽  
Light Chain ◽  
Rho Kinase ◽  
Muscle Cells ◽  
Inhibitory Effects ◽  
Gastric Smooth Muscle ◽  
Camp And Cgmp ◽  
Cgmp Formation

Inhibitory neurotransmitters, chiefly nitric oxide and vasoactive intestinal peptide, increase cyclic nucleotide levels and inhibit muscle contraction via inhibition of myosin light chain (MLC) kinase and activation of MLC phosphatase (MLCP). H2S produced as an endogenous signaling molecule synthesized mainly from l-cysteine via cystathionine-γ-lyase (CSE) and cystathionine-β-synthase (CBS) regulates muscle contraction. The aim of this study was to analyze the expression of CSE and H2S function in the regulation of MLCP activity, 20-kDa regulatory light chain of myosin II (MLC20) phosphorylation, and contraction in isolated gastric smooth muscle cells. Both mRNA expression and protein expression of CSE, but not CBS, were detected in smooth muscle cells of rabbit, human, and mouse stomach. l-cysteine, an activator of CSE, and NaHS, a donor of H2S, inhibited carbachol-induced Rho kinase and PKC activity, Rho kinase-sensitive phosphorylation of MYPT1, PKC-sensitive phosphorylation of CPI-17, and MLC20 phosphorylation and sustained muscle contraction. The inhibitory effects of l-cysteine, but not NaHS, were blocked upon suppression of CSE expression by siRNA or inhibition of its activity by dl-propargylglycine (PPG) suggesting that the effect of l-cysteine is mediated via activation of CSE. Glibenclamide, an inhibitor of KATP channels, had no effect on the inhibition of contraction by H2S. Both l-cysteine and NaHS had no effect on basal cAMP and cGMP levels but augmented forskolin-induced cAMP and SNP-induced cGMP formation. We conclude that both endogenous and exogenous H2S inhibit muscle contraction, and the mechanism involves inhibition of Rho kinase and PKC activities and stimulation of MLCP activity leading to MLC20 dephosphorylation and inhibition of muscle contraction.

Characterization of opioid receptors on smooth muscle cells from guinea pig stomach

1992 ◽  
Vol 262 (3) ◽  
pp. G461-G469 ◽  
Author(s):  
L. Zhang ◽  
Z. F. Gu ◽  
T. Pradhan ◽  
R. T. Jensen ◽  
P. N. Maton
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Opioid Receptors ◽  
Muscle Cells ◽  
Receptor Subtypes ◽  
Selective Antagonist ◽  
Kappa Agonist ◽  
Gastric Smooth Muscle ◽  
Selective Ligand ◽  
Guinea Pig Stomach

On the basis of opioid-stimulated contraction of dispersed gastric smooth muscle cells it has been suggested that these cells possess opioid receptors of three subtypes: kappa (kappa), mu (mu), and delta (delta). We have used selective peptidase-resistant radioligands, agonists and antagonists, to examine receptor subtypes on dispersed gastric smooth muscle cells from guinea pigs prepared by collagenase digestion. The kappa-agonist U-50488H, the mu-agonist [D-Ala2,N-Me-Phe4,Gly5-ol]enkephalin (DAGO), and the delta-agonist [D-Pen2,Pen5]enkephalin (DPDPE) each caused muscle contraction. The concentrations required to caused half-maximal contraction were U50488H (6 pM) greater than DAGO (13 pM) greater than DPDPE (6 nM). The abilities of these agonists to inhibit binding of [3H]U-69593 (kappa-preferring) by 50% were U50488H (43 nM) greater than DAGO (43 microM) greater than DPDPE (200 microM). Their abilities to inhibit binding of [3H]naloxone (mu-preferring) by 50% were DAGO (0.2 microM) greater than U50488H (10 microM) greater than DPDPE (greater than 100 microM). No binding could be detected with the delta-selective ligand [3H]DPDPE. The kappa-preferring antagonist Mr2266 (10 nM) preferentially inhibited contraction stimulated by the kappa-agonist U50488H, and naltrexone (10 nM) (mu-selective antagonist) preferentially inhibited contraction stimulated by the mu-agonist DAGO. ICI 174864 (200 microM; delta-selective antagonist) had no effect on contraction stimulated by mu-, kappa-, or delta-agonists. Contraction stimulated by the delta-agonist DPDPE was inhibited by both kappa- and mu-receptor antagonists. Studies on the effect of the antagonists on binding of [3H]naloxone and [3H]U69593 also provided evidence for kappa- and mu-sites but nor for delta-sites.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Activation of G protein-coupled bile acid receptor, TGR5, induces smooth muscle relaxation via both Epac- and PKA-mediated inhibition of RhoA/Rho kinase pathway

2013 ◽  
Vol 304 (5) ◽  
pp. G527-G535 ◽  
Author(s):  
Senthilkumar Rajagopal ◽  
Divya P. Kumar ◽  
Sunila Mahavadi ◽  
Sayak Bhattacharya ◽  
Ruizhe Zhou ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Kinase Activity ◽  
Muscle Relaxation ◽  
Rho Kinase ◽  
Muscle Cells ◽  
Receptor Activation ◽  
Gastric Smooth Muscle ◽  
Selective Ligand ◽  
Gastric Muscle ◽  
Kinase Pathway

The present study characterized the TGR5 expression and the signaling pathways coupled to this receptor that mediates the relaxation of gastric smooth muscle. TGR5 was detected in gastric muscle cells by RT-PCR and Western blotting. Treatment of cells with the TGR5-selective ligand oleanolic acid (OA) activated Gαs, but not Gαq, Gαi1, Gαi2, or Gαi3, and increased cAMP levels. OA did not elicit contraction, but caused relaxation of carbachol-induced contraction of gastric muscle cells from wild-type mice, but not tgr5−/− mice. OA, but not a selective exchange protein activated by cAMP (Epac) ligand (8-pCPT-2′-O-Me-cAMP), caused phosphorylation of RhoA and the phosphorylation was blocked by the PKA inhibitor, myristoylated PKI, and by the expression of phosphorylation-deficient mutant RhoA (S188A). Both OA and Epac ligand stimulated Ras-related protein 1 (Rap1) and inhibited carbachol (CCh)-induced Rho kinase activity. Expression of RhoA (S188A) or PKI partly reversed the inhibition of Rho kinase activity by OA but had no effect on inhibition by Epac ligand. However, suppression of Rap1 with siRNA blocked the inhibition of Rho kinase by Epac ligand, and partly reversed the inhibition by OA; the residual inhibition was blocked by PKI. Muscle relaxation in response to OA, but not Epac ligand, was partly reversed by PKI. We conclude that activation of TGR5 causes relaxation of gastric smooth muscle and the relaxation is mediated through inhibition of RhoA/Rho kinase pathway via both cAMP/Epac-dependent stimulation of Rap1 and cAMP/PKA-dependent phosphorylation of RhoA at Ser188. TGR5 receptor activation on smooth muscle reveals a novel mechanism for the regulation of gut motility by bile acids.

Role of Potassium Channels in the Effects of Hydrogen Sulfide on Contractility of Gastric Smooth Muscle Cells in Rats

2018 ◽  
Vol 54 (5) ◽  
pp. 400-407 ◽  
Author(s):  
I. F. Shaidullov ◽  
M. U. Shafigullin ◽  
L. M. Gabitova ◽  
F. G. Sitdikov ◽  
A. L. Zefirov ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Hydrogen Sulfide ◽  
Potassium Channels ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
Gastric Smooth Muscle

Muscarinic receptor size on smooth muscle cells and membranes

1986 ◽  
Vol 251 (2) ◽  
pp. G195-G200
Author(s):  
S. M. Collins ◽  
C. Y. Jung ◽  
A. K. Grover
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Muscarinic Receptor ◽  
Plasma Membranes ◽  
Muscle Cells ◽  
High Energy ◽  
Membrane Preparation ◽  
Galactose Oxidase ◽  
Radiation Inactivation ◽  
Gastric Smooth Muscle

The loss of [3H]quinuclidinyl benzilate ([3H]QNB) binding following high-energy radiation was used to compare the muscarinic receptor size on single smooth muscle cells isolated by collagenase digestion from the canine stomach and on plasma membranes derived from intact gastric smooth muscle without exposure to exogenous proteolysis. Radiation inactivation of galactose oxidase (68 kdaltons), yeast alcohol dehydrogenase (160 kdaltons), and pyruvate kinase (224 kdaltons) activities were used as molecular-weight standards. Radiation inactivation of [3H]QNB binding to rat brain membranes, which gave a target size of 86 kdaltons, served as an additional control. In isolated smooth muscle cells, the calculated size of the muscarinic receptor was 80 +/- 8 kdaltons. In contrast, in a smooth muscle enriched plasma membrane preparation, muscarinic receptor size was significantly smaller at 45 +/- 3 kdaltons. Larger molecular sizes were obtained either in the presence of protease inhibitors (62 +/- 4 kdaltons) or by using a crude membrane preparation of gastric smooth muscle 86 +/- 7 kdaltons).

Gastric smooth muscle cells possess two classes of endothelin receptors but only one alters contraction

1994 ◽  
Vol 266 (4) ◽  
pp. G713-G721 ◽  
Author(s):  
Y. Kitsukawa ◽  
Z. F. Gu ◽  
P. Hildebrand ◽  
R. T. Jensen
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Muscle Contraction ◽  
Muscle Cells ◽  
The Other ◽  
Stomach Muscle ◽  
Dependent Manner ◽  
High Affinity ◽  
Gastric Smooth Muscle ◽  
Eta Receptor

Endothelin (ET)-like immunoreactivity and ET binding sites are widely distributed in the gastrointestinal tract, and ET causes contraction of stomach muscle strips. To determine whether ETs could interact with gastric smooth muscle cells directly and alter function, we measured binding of 125I-ET-1, 125I-ET-2, and 125I-ET-3 to dispersed gastric smooth muscle cells from guinea pig and their abilities to alter cell length. Each ligand bound in a time- and temperature-dependent manner, which was specific and saturable. Analysis of the dose-inhibition curves of both ET-1 and ET-3 for binding of each ligand indicated the presence of two classes of receptors, one class (ETA receptor) with a high affinity for ET-1 and ET-2 but a low affinity for ET-3, and the other (ETB receptor) with a high affinity for ET-1, ET-2, and ET-3. The ligands were rapidly internalized by both receptors; however, it was greater with ETA receptors. ET-1 stimulated muscle contraction (50% effective concentration approximately 2 nM), whereas ET-3 did not stimulate contraction or cause relaxation. These results demonstrate that gastric smooth muscle cells possess two classes of ET receptors. One type (ETA) has a high affinity for ET-1 and ET-2 and a low affinity for ET-3, and receptor occupation results in rapid ligand internalization and muscle contraction; the other type (ETB) has a high affinity for ET-1, ET-2, and ET-3, and receptor occupation results in a lesser degree of ligand internalization than the ETA receptor and does not alter contractile behavior.

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