scholarly journals Non-cholinergic, excitatory junction potentials in intestinal smooth muscle cells

1976 ◽  
Vol 26 ◽  
pp. 56
Author(s):  
Hidenori Ohashi ◽  
Kyozo Naito ◽  
Tadashi Takewaki ◽  
Toshiaki Okada
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
Intestinal Smooth Muscle ◽  
Excitatory Junction Potentials

IGFBP-3 activates TGF-β receptors and directly inhibits growth in human intestinal smooth muscle cells

2004 ◽  
Vol 287 (4) ◽  
pp. G795-G802 ◽  
Author(s):  
John F. Kuemmerle ◽  
Karnam S. Murthy ◽  
Jennifer G. Bowers
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Nuclear Translocation ◽  
Thymidine Incorporation ◽  
Muscle Cells ◽  
Serine Phosphorylation ◽  
Intestinal Smooth Muscle ◽  
Igf I ◽  
Tgf Β1 ◽  
Igfbp 3

We have shown that human intestinal smooth muscle cells produce IGF-I and IGF binding protein-3 (IGFBP-3). Endogenous IGF-I acts in autocrine fashion to stimulate growth of these cells. IGFBP-3 inhibits the binding of IGF-I to its receptor and thereby inhibits IGF-I-stimulated growth. In several carcinoma cell lines and some normal cells, IGFBP-3 regulates growth independently of IGF-I. Two mechanisms for this effect have been identified: IGFBP-3 can directly activate transforming growth factor-β (TGF-β) receptors or it can undergo direct nuclear translocation. The aim of the present study was to determine whether IGFBP-3 acts independently of IGF-I and to characterize the mechanisms mediating this effect in human intestinal smooth muscle cells. The direct effects of IGFBP-3 were determined in the presence of an IGF-I receptor antagonist to eliminate its IGF-I-dependent effects. Affinity labeling of TGF-β receptors (TGF-βRI, TGF-βRII, and TGF-βRV) with 125I-labeled TGF-β1 showed that IGFBP-3 displaced binding to TGF-βRII and TGF-βRV in a concentration-dependent fashion. IGFBP-3 stimulated TGF-βRII-dependent serine phosphorylation (activation) of both TGF-βRI and of its primary substrate, Smad2(Ser465/467). IGFBP-3 also caused IGF-I-independent inhibition of basal [3H]thymidine incorporation. The effects of IGFBP-3 on Smad2 phosphorylation and on smooth muscle cell proliferation were independent of TGF-β1 and were abolished by transfection of Smad2 siRNA. Immunoneutralization of IGFBP-3 increased basal [3H]thymidine incorporation, implying that endogenous IGFBP-3 inhibits proliferation. We conclude that endogenous IGFBP-3 directly inhibits proliferation of human intestinal smooth muscle cells by activation of TGF-βRI and Smad2, an effect that is independent of its effect on IGF-I-stimulated growth.

Galanin contracts and relaxes guinea pig and canine intestinal smooth muscle cells through distinct receptors

1995 ◽  
Vol 108 (1) ◽  
pp. 3-11 ◽  
Author(s):  
Alain Botella ◽  
Michel Delvaux ◽  
Jean Fioramonti ◽  
Jacques Frexinos ◽  
Lionel Bueno
Keyword(s):  
Smooth Muscle ◽  
Guinea Pig ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
Intestinal Smooth Muscle

IGF-I increases IGFBP-5 and collagen α1(I) mRNAs by the MAPK pathway in rat intestinal smooth muscle cells

2004 ◽  
Vol 286 (5) ◽  
pp. G777-G783 ◽  
Author(s):  
Xiping Xin ◽  
Yong Tai Hou ◽  
Lina Li ◽  
Phyllissa Schmiedlin-Ren ◽  
Gregory M. Christman ◽  
...  
Keyword(s):  
Gene Regulation ◽  
Smooth Muscle ◽  
Crohn’S Disease ◽  
Smooth Muscle Cells ◽  
Mapk Pathway ◽  
Muscle Cells ◽  
Intestinal Smooth Muscle ◽  
Concurrent Treatment ◽  
Igf I ◽  
Docking Proteins

IGF-I is a potent fibrogenic growth factor that stimulates proliferation of intestinal smooth muscle cells and increases synthesis of collagen and IGF-I-binding proteins by the cells. These processes contribute to intestinal fibrosis that develops in patients with Crohn's disease and in Lewis-strain rats with experimental Crohn's disease. The aim of this study was to determine which early docking proteins are associated with IGF-I receptor signal transduction and which transduction pathway is involved in IGF-I-mediated gene regulation in intestinal smooth muscle cells. Primary cultures of smooth muscle cells isolated from the muscularis externa of the distal colon of Lewis rats were treated with IGF-I (100 ng/ml). Immunoprecipitation studies demonstrated that IGF-I stimulation resulted in tyrosine phosphorylation of IRS-1, IRS-2, and Shc. Coimmunoprecipitation demonstrated a close association between the IGF-I receptor and these three early docking proteins. Concurrent treatment with the MAPK inhibitor PD98059 (10 μM) resulted in an inhibition of the IGF-I-mediated increase in IGFBP-5 and collagen α1(I) mRNAs, while concurrent treatment with the phosphatidylinositol 3-kinase (PI3-K) inhibitor wortmannin (100 nM) had no effect. In additional experiments, cells were transiently transfected with adenoviral vectors dominantly expressing inactive mutant Akt or constitutively expressing wild-type Akt. In both cases, the IGF-I-mediated increase in collagen I protein did not differ from that observed in control cultures that had been transfected with an adenoviral vector carrying the LacZ reporter gene. These results suggest that the MAPK pathway is key to IGF-I-mediated gene regulation in intestinal smooth muscle cells, whereas data do not suggest a role for the Akt-dependent pathway in our system.

Multiple types of voltage-dependent Ca channels in mammalian intestinal smooth muscle cells

1989 ◽  
Vol 414 (4) ◽  
pp. 401-409 ◽  
Author(s):  
M. Yoshino ◽  
T. Someya ◽  
A. Nishio ◽  
K. Yazawa ◽  
T. Usuki ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
Intestinal Smooth Muscle ◽  
Ca Channels ◽  
Voltage Dependent

Nongenomic effects of progesterone on human intestinal smooth muscle cells

1996 ◽  
Vol 271 (2) ◽  
pp. G370-G376 ◽  
Author(s):  
K. Bielefeldt ◽  
L. Waite ◽  
F. M. Abboud ◽  
J. L. Conklin
Keyword(s):  
Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
Ionic Currents ◽  
Calcium Currents ◽  
Intestinal Smooth Muscle ◽  
Calcium Signal ◽  
Membrane Excitability ◽  
Patch Clamp Technique ◽  
Nongenomic Effects

Previous experiments demonstrated that progesterone affects intestinal smooth muscle cells through genomic and nongenomic pathways. We hypothesized that the nongenomic effect was mediated by changes in membrane excitability. We studied the effects of progesterone and other steroid hormones on a human intestinal smooth muscle cell line, using the whole cell patch-clamp technique. Ionic currents were elicited through steps from -70 mV to various test potentials. Progesterone dose-dependently reduced calcium currents. The decrease in inward current was partly due to a shift in the steady-state inactivation to more hyperpolarized potentials. This effect did not involve gene transcription, since it was not blocked by the progesterone antagonist ZK-98-299. The progesterone analogue 5-beta-dihydroprogesterone also decreased calcium currents, whereas its stereoisomer, 5-alpha- dihydroprogesterone, did not affect the properties of voltage-sensitive ion channels. Similarly, estradiol and dexamethasone did not alter inward currents. We conclude that progestins exert their nongenomic effects on intestinal smooth muscle cells by decreasing calcium currents. The change in the calcium signal may contribute to the reduction in muscle contraction observed after progesterone.

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