Effect of NO donors on protein phosphorylation in intact vascular and nonvascular smooth muscles

2001 ◽  
Vol 280 (4) ◽  
pp. H1565-H1580 ◽  
Author(s):  
James K. Hennan ◽  
Jack Diamond
Keyword(s):  
Smooth Muscle ◽  
Protein Kinase ◽  
Protein Phosphorylation ◽  
Vas Deferens ◽  
Smooth Muscles ◽  
Rat Aorta ◽  
Rat Vas Deferens ◽  
Two Dimensional Gel Electrophoresis ◽  
Relaxant Response ◽  
Underlying Mechanisms

It is generally well accepted that nitrovasodilator-induced relaxation of vascular smooth muscle involves elevation of cGMP and activation of a specific cGMP-dependent protein kinase [protein kinase G (PKG)]. However, the protein targets of PKG and the underlying mechanisms by which this kinase leads to a relaxant response have not been elucidated. Several types of smooth muscle, including rat myometrium and vas deferens, are not relaxed by sodium nitroprusside, even at concentrations that produce marked elevation of cGMP and activation of PKG. The main objective of our studies was to compare PKG-mediated protein phosphorylation in intact rat aorta, rat myometrium, and rat vas deferens using two-dimensional gel electrophoresis. In intact rat aorta, seven PKG substrates were detected during relaxation of the tissue. None of the PKG substrates identified in the rat aorta appeared to be phosphorylated in the myometrium or vas deferens after administration of various cGMP-elevating agents. Thus the failure of the rat myometrium and rat vas deferens to relax in the face of cGMP elevation and PKG activation may be due to a lack of PKG substrate phosphorylation.

scholarly journals Subcellular-membrane characterization of [3H]ryanodine-binding sites in smooth muscle

1993 ◽  
Vol 290 (1) ◽  
pp. 259-266 ◽  
Author(s):  
Z D Zhang ◽  
C Y Kwan ◽  
E E Daniel
Keyword(s):  
Smooth Muscle ◽  
Ryanodine Receptor ◽  
Binding Sites ◽  
Vas Deferens ◽  
Smooth Muscles ◽  
Rat Vas Deferens ◽  
Detailed Characterization ◽  
Release Channel ◽  
Subcellular Membrane

The plant alkaloid ryanodine, known to interact selectively with the intracellular Ca(2+)-release channel in skeletal and cardiac muscles, has been repeatedly reported to affect smooth-muscle contractile functions that are consistent with its intracellular action at the Ca(2+)-release channel sites. Direct evidence for the binding of [3H]ryanodine to smooth-muscle membranes is sparse. Following our recent detailed characterization of functional effects of ryanodine and a preliminary report on the presence of [3H]ryanodine binding sites in rat vas deferens smooth muscle, we now report in this study a detailed characterization of binding of [3H]ryanodine to smooth muscle at the subcellular-membrane level. The ryanodine receptor in rat vas deferens muscle layer is primarily of smooth-muscle origin and is localized at the subcellular membrane site that is consistent with its role as a Ca(2+)-release channel in the sarcoplasmic reticulum (SR). Ryanodine binding to its receptor is Ca(2+)-dependent, with half-maximal binding occurring within the physiologically relevant cytosolic Ca2+ concentration. It is also sensitive to many factors, including change in Mg2+ concentration, ionic strength and osmolarity across the membrane vesicles. Agents known to inhibit (Ruthenium Red, Mg2+) or enhance (caffeine, Na+, K+) the Ca(2+)-induced Ca2+ release also inhibit or enhance the binding of ryanodine. Quantitative differences in ryanodine receptors exist among smooth muscles and do not seem to parallel their SR contents. Results from the present study indicate both the need and the basis for future investigations of the functional role of the ryanodine receptor in different smooth muscles.

Polydatin Attenuates Carbachol-induced Contraction of Guinea Pig Gallbladder

2019 ◽  
Vol 18 (1) ◽  
pp. 34-38
Author(s):  
Chen Lei ◽  
Pan Xiang ◽  
Shen Yonggang ◽  
Song Kai ◽  
Zhong Xingguo ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Guinea Pig ◽  
Smooth Muscles ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Cyclic Guanosine Monophosphate ◽  
Guanosine Monophosphate ◽  
Dependent Manner ◽  
Underlying Mechanisms ◽  
Dose Dependent

The aim of this study was to determine whether polydatin, a glucoside of resveratrol isolated from the root of Polygonum cuspidatum, warranted development as a potential therapeutic for ameliorating the pain originating from gallbladder spasm disorders and the underlying mechanisms. Guinea pig gallbladder smooth muscles were treated with polydatin and specific inhibitors to explore the mechanisms underpinning polydatin-induced relaxation of carbachol-precontracted guinea pig gallbladder. Our results shown that polydatin relaxed carbachol-induced contraction in a dose-dependent manner through the nitric oxide/cyclic guanosine monophosphate/protein kinase G and the cyclic adenosine monophosphate/protein kinase A signaling pathways as well as the myosin light chain kinase and potassium channels. Our findings suggested that there was value in further exploring the potential therapeutic use of polydatin in gallbladder spasm disorders.

Ca2+-independent contraction of longitudinal ileal smooth muscle is potentiated by a zipper-interacting protein kinase pseudosubstrate peptide

2009 ◽  
Vol 297 (2) ◽  
pp. G361-G370 ◽  
Author(s):  
Eikichi Ihara ◽  
Lori Moffat ◽  
Meredith A. Borman ◽  
Jennifer E. Amon ◽  
Michael P. Walsh ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Protein Kinase ◽  
Conformational Changes ◽  
Kinase Inhibitor ◽  
Smooth Muscles ◽  
Dominant Negative ◽  
Myosin Phosphatase ◽  
Interacting Protein ◽  
Zipper Interacting Protein Kinase

As a regulator of smooth muscle contraction, zipper-interacting protein kinase (ZIPK) can directly phosphorylate the myosin regulatory light chains (LC20) and produce contractile force. Synthetic peptides (SM-1 and AV25) derived from the autoinhibitory region of smooth muscle myosin light chain kinase can inhibit ZIPK activity in vitro. Paradoxically, treatment of Triton-skinned ileal smooth muscle strips with AV25, but not SM-1, potentiated Ca2+-independent, microcystin- and ZIPK-induced contractions. The AV25-induced potentiation was limited to ileal and colonic smooth muscles and was not observed in rat caudal artery. Thus the potentiation of Ca2+-independent contractions by AV25 appeared to be mediated by a mechanism unique to intestinal smooth muscle. AV25 treatment elicited increased phosphorylation of LC20 (both Ser-19 and Thr-18) and myosin phosphatase-targeting subunit (MYPT1, inhibitory Thr-697 site), suggesting involvement of a Ca2+-independent LC20 kinase with coincident inhibition of myosin phosphatase. The phosphorylation of the inhibitor of myosin phosphatase, CPI-17, was not affected. The AV25-induced potentiation was abolished by pretreatment with staurosporine, a broad-specificity kinase inhibitor, but specific inhibitors of Rho-associated kinase, PKC, and MAPK pathways had no effect. When a dominant-negative ZIPK [kinase-dead ZIPK(1–320)-D161A] was added to skinned ileal smooth muscle, the potentiation of microcystin-induced contraction by AV25 was blocked. Furthermore, pretreatment of skinned ileal muscle with SM-1 abolished AV25-induced potentiation. We conclude, therefore, that, even though AV25 is an in vitro inhibitor of ZIPK, activation of the ZIPK pathway occurs following application of AV25 to permeabilized ileal smooth muscle. Finally, we propose a mechanism whereby conformational changes in the pseudosubstrate region of ZIPK permit augmentation of ZIPK activity toward LC20 and MYPT1 in situ. AV25 or molecules based on its structure could be used in therapeutic situations to induce contractility in diseases of the gastrointestinal tract associated with hypomotility.

scholarly journals Electrophysiology of Syncytial Smooth Muscle

2019 ◽  
Vol 13 ◽  
pp. 117906951882191 ◽  
Author(s):  
Rohit Manchanda ◽  
Shailesh Appukuttan ◽  
Mithun Padmakumar
Keyword(s):  
Smooth Muscle ◽  
Action Potentials ◽  
Signal Analysis ◽  
Computational Models ◽  
Vas Deferens ◽  
Contractile Activity ◽  
Smooth Muscles ◽  
Biophysical Analysis ◽  
Recent Developments ◽  
The Many

As in other excitable tissues, two classes of electrical signals are of fundamental importance to the functioning of smooth muscles: junction potentials, which arise from neurotransmission and represent the initiation of excitation (or in some instances inhibition) of the tissue, and spikes or action potentials, which represent the accomplishment of excitation and lead on to contractile activity. Unlike the case in skeletal muscle and in neurons, junction potentials and spikes in smooth muscle have been poorly understood in relation to the electrical properties of the tissue and in terms of their spatiotemporal spread within it. This owes principally to the experimental difficulties involved in making precise electrical recordings from smooth muscles and also to two inherent features of this class of muscle, ie, the syncytial organization of its cells and the distributed innervation they receive, which renders their biophysical analysis problematic. In this review, we outline the development of hypotheses and knowledge on junction potentials and spikes in syncytial smooth muscle, showing how our concepts have frequently undergone radical changes and how recent developments hold promise in unraveling some of the many puzzles that remain. We focus especially on computational models and signal analysis approaches. We take as illustrative examples the smooth muscles of two organs with distinct functional characteristics, the vas deferens and urinary bladder, while also touching on features of electrical functioning in the smooth muscles of other organs.

Ca2+ handling properties of microsomal subfractions of rat vas deferens smooth muscle

1984 ◽  
Vol 62 (1) ◽  
pp. 76-79 ◽  
Author(s):  
A. K. Grover ◽  
C. Y. Kwan
Keyword(s):  
Smooth Muscle ◽  
Concentration Dependence ◽  
Vas Deferens ◽  
Membrane Vesicles ◽  
Rat Vas Deferens ◽  
Enzyme Marker ◽  
Isopycnic Centrifugation ◽  
Stimulation Of ◽  
Ph Profiles

The rat vas deferens smooth muscle microsomes on isopycnic centrifugation gave two fractions, namely F2 (15–30% sucrose) and F3 (30–40% sucrose), with comparable ATP-dependent azide-insensitive Ca2+-uptake capacities, although these fractions differed from each other in various enzyme marker activities. The fractions F2 and F3 also show similar pH profiles for the ATP-independent and ATP-dependent Ca2+ uptake, and similar ionized Ca2+-concentration dependence for the ATP-dependent Ca2+ uptake. However, the fractions F2 and F3 differ from each other in that: (a) F3 shows higher permeability to Ca2+, and (b) F3 shows higher stimulation of the ATP-dependent Ca2+ uptake by oxalate. The F3 fraction can also be used to obtain membrane vesicles loaded with Ca2+ oxalate in the presence of ATP. However, the yield of the Ca2+ oxalate enriched fraction is too low to permit their further characterization.

Protein phosphorylation in cardiac and vascular smooth muscle

1981 ◽  
Vol 241 (2) ◽  
pp. H117-H128 ◽  
Author(s):  
M. Barany ◽  
K. Barany
Keyword(s):  
Smooth Muscle ◽  
Protein Phosphorylation ◽  
Light Chain ◽  
Myosin Light Chain ◽  
Current Knowledge ◽  
Smooth Muscles ◽  
Arterial Smooth Muscle ◽  
Cardiac Sarcoplasmic Reticulum ◽  
The Many ◽  
Contraction Cycle

In the heart and arterial smooth muscles, several proteins are phosphorylated. This review summarizes our current knowledge about these phosphoproteins and their possible role in the function of these muscles. In the contractile apparatus, the phosphorylation of myosin light chain seems to be an integral part of the contraction cycle of arterial smooth muscle. However, in the heart the relationship between light chain phosphorylation-dehosphorylation and systolic-diastolic states remains open. In the heart, the phosphorylation of the inhibitory subunit of troponin, a myofibrillar protein, parallels the positive inotropic response induced by beta-adrenergic agonists. It seems likely that this phosphorylation is involved in the physiological stimulation of the heart by epinephrine. Cardiac sarcoplasmic reticulum contains a low-molecular-weight protein, phospholamban, the phosphorylation of which is required for Ca2+ transport. Ion fluxes through the heart sarcolemma may also be controlled through membrane protein phosphorylation. Key enzymes of the energy-yielding pathways in the heart, the pyruvate dehydrogenase multienzyme complex and phosphorylase, are turned on and off by phosphorylation-dephosphorylation mechanisms. Our understanding of protein phosphorylation in the heart has advanced greatly. In contrast, with the exception of the myosin light chain, much less is known about the many proteins phosphorylated in arterial smooth muscle.

scholarly journals Regulation of smooth muscle contractility by the epithelium in rat vas deferens: role of ATP-induced release of PGE2

2008 ◽  
Vol 586 (20) ◽  
pp. 4843-4857 ◽  
Author(s):  
Ye Chun Ruan ◽  
Zhe Wang ◽  
Jian Yang Du ◽  
Wu Lin Zuo ◽  
Jing Hui Guo ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Vas Deferens ◽  
Rat Vas Deferens ◽  
Muscle Contractility ◽  
Smooth Muscle Contractility

Actin cytoskeletal dynamics in smooth muscle contraction

2005 ◽  
Vol 83 (10) ◽  
pp. 851-856 ◽  
Author(s):  
William T Gerthoffer
Keyword(s):  
Smooth Muscle ◽  
Protein Kinase ◽  
Actin Cytoskeleton ◽  
Protein Kinases ◽  
Smooth Muscles ◽  
Small Gtpases ◽  
Signaling Cascades ◽  
Contractile Element ◽  
Muscle Plasticity ◽  
Wide Range

Smooth muscles develop isometric force over a very wide range of cell lengths. The molecular mechanisms of this phenomenon are undefined, but are described as reflecting "mechanical plasticity" of smooth muscle cells. Plasticity is defined here as a persistent change in cell structure or function in response to a change in the environment. Important environmental stimuli that trigger muscle plasticity include chemical (e.g., neurotransmitters, autacoids, and cytokines) and external mechanical signals (e.g., applied stress and strain). Both kinds of signals are probably transduced by ionic and protein kinase signaling cascades to alter gene expression patterns and changes in the cytoskeleton and contractile system. Defining the signaling mechanisms and effector proteins mediating phenotypic and mechanical plasticity of smooth muscles is a major goal in muscle cell biology. Some of the signaling cascades likely to be important include calcium-dependent protein kinases, small GTPases (Rho, Rac, cdc42), Rho kinase, protein kinase C (PKC), Src family tyrosine kinases, mitogen-activated protein (MAP) kinases, and p21 activated protein kinases (PAK). There are many potential targets for these signaling cascades including nuclear processes, metabolic pathways, and structural components of the cytoskeleton. There is growing appreciation of the dynamic nature of the actin cytoskeleton in smooth muscles and the necessity for actin remodeling to occur during contraction. The actin cytoskeleton serves many functions that are probably critical for muscle plasticity including generation and transmission of force vectors, determination of cell shape, and assembly of signal transduction machinery. Evidence is presented showing that actin filaments are dynamic and that actin-associated proteins comprising the contractile element and actin attachment sites are necessary for smooth muscle contraction.Key words: integrin, muscle mechanics, paxillin, Rho, HSP27.

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