Talk:Smooth muscle

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Someone please correct the sentence "each cell is spindle-shaped, 20-500 micrometers in is ~6:1 in striated muscle and ~15:1 in smooth muscle" - perhaps it's about cell length:width proportions, but I always thought that smooth muscles are less elongated than striated.Porridge (talk) 09:49, 23 May 2009 (UTC)[reply]

Well I messed around and have changed most of the article. It maybe too complicated, and surely needs editing. I can provide references for any facts, but I think some of it is too detailed for an encyclopedia. Help me clip down. GetAgrippa 21:50, 6 October 2006 (UTC)[reply]

yeh somebody make the part about function a little less complicated please

I made the Function section a bit easier to read. Jamesters 23:22, 16 November 2006 (UTC)[reply]

In my studies,"Smooth muscle tissue" always seemed to be a slang term. The more professional term that was used was "Visceral muscle tissue". Isn't Visceral muscle tissue the official term for it now? Shouldn't this article be renamed? I may be incorrect. I'm not going to change it right now myself since I am not confident enough. It may need to be considered though. Jamesters 23:22, 16 November 2006 (UTC)[reply]

Jamesters there is Vascular and Visceral Smooth muscle and it refers to its location. Vascular- arteries and veins or viscera-gut,reproductive tract, respiratory tract, etc.GetAgrippa 01:01, 17 November 2006 (UTC)[reply]

All right, that makes sense. Thanks for clarifying! Jamesters 10:58, 17 November 2006 (UTC)[reply]

Is someone able to explain "slow waves rhythm" (don't know exact English term), decribed in Guyton's physiology as a process characterictic to smooth muscles, that can lead to creation of action potential?

What206.74.157.2 (talk) 15:10, 15 April 2011 (UTC)[reply]

Smooth muscle from some sources displays spontaneous rhythmic activity and autonomic innervation influences contractility. In the gut interstitial cells of Cajal are specialized pacemaker cells. I'll read up on it. GetAgrippa 22:12, 20 November 2006 (UTC)[reply]

Fix-up

For being a member of two wikiprojects, this article shows poor composition and format. If someone would be able to clean it up, that would be great. The information is not structured with a focus on clean, informative text, but rather galloping ideas that skip over some significant points, such as the ones I added. DRosenbach ^{(Talk | Contribs)} 18:56, 23 July 2007 (UTC)[reply]

I agree. The article was a stub. I added to what was present by vomiting a bunch of information on the page touching on various subjects. The contraction relaxation info concentrates on cell signalling rather than biomechanics. A section on the biomechanical properties of various smooth muscle preparations would be interesting but probably overkill for an encyclopedia. Perhaps a secton of neurohumoral influences that effect smooth muscle containing tissues of the body-gut, skin goose bumps, erection, etc. This article doesn't generate much interest so I hadn't even bothered to add any references because I think much of what I added is probably not appropriate for an encyclopedia article anyways and will be removed. I had hoped someone familiar with this Wiki's format and experienced at writing encyclopedia articles would organize and rewrite it into something more useful. Subsections on cell signalling and biomechanics (stress-relaxation, hysteresis, shortening velocities of various tissues, etc.) might be appropriate. Perhaps a section on differences in proteins such as actin and myosin isoforms, lack of troponin and titin, significant other proteins like caldesmon and calponin, etc. Most of this Wiki's articles concerning muscle and contraction are poorly written and the emphasis is always vertebrate and particularly human rather than a general biological perspective that would encompass invertebrate and vertebrate. GetAgrippa 14:15, 24 July 2007 (UTC)[reply]

Hmm...I don't think that the focus of the article being human smooth muscle is at all a problem -- a quick survery of articles such as maxillary central incisor, gall bladder and trigeminal nerve all show a predominance of human anatomy and physiology over those of other species, vertebrate or not. This discussion has taken place at least in one place (hmmm...can't remember where exactly, but I know it had to do with the tooth article, in terms of "who" or "what" is the focus of our articles when it comes to multiple species and their possession of various anatomical and physiologic characteristics.)

I think the smooth muscle article should focus on the basics of smooth muscle anatomy and physiology, and discuss the differences of smooth in relation to skeletal and cardiac muscle.

I'll volunteer to redraft this article, if you give me two weeks or so. DRosenbach ^{(Talk | Contribs)} 02:09, 25 July 2007 (UTC)[reply]

The nomenclature used can be confusing and I noted on line searches yielded similar misinformation and confusion. Visceral smooth muscle can be multiunit or single unit. Including blood vessels with visceral smooth muscle is confusing as it is vascular smooth muscle. Smooth muscle from different visceral sources gut, etc. and from different areas of the vasculature are very different beast. I would think that an encyclopedia would be more general biology and not limited to vertebrate or human in its scope, and NPOV should encourage a more general article. I like your idea to compare skeletal, cardiac, and smooth muscle because that would bring up the topics of titin isoforms and stiffness (and the lack of titin in smooth muscle), the differences in shortening velocity-myosin isoforms and ADP affinity,etc, the lack of troponin in smooth muscle and calcium dependent MLC phosphorylation, differences in intracellular structure and content, differences in ionic channels. It could really make a nice separate article. In any case I am pleased you are willing to work on the article and I can assist in finding references for any given posit. Regards GetAgrippa 16:06, 25 July 2007 (UTC)[reply]

Advanced section

The advanced section of contraction and relaxation is great info but probably not appropriate for this encyclopedia. I paired the article down by removing section so we can fix this article. I believe some of the info can be mentioned in other articles or perhaps another article with a different emphasis or cherry pick some to put in basic section. I will move the section to here for now:

Section on Advanced Contraction and Relaxation removed for development.

Muscle can be characterized as two types: tonic and phasic which describes their response to depolarizing high potassium solutions. Tonic smooth muscle contracts and relaxes slowly and exhibits force maintenance such as vascular smooth muscle. Force maintenance is the maintaining of a contraction for a prolonged time with little energy utilization. The phasic smooth muscle contracts and relaxes rapidly such as gut smooth muscle. This phasic response is useful to massage substances through the lumen of the gastrointestinal tract during peristalsis. Vascular smooth muscle (walls of arteries and veins) and visceral smooth muscle (wall of gastrointestinal tract, urogenital tract, iris) is another distinction in common use to discriminate the kind of smooth muscle. Contractions in vertebrate smooth muscle can be initiated by stretch, gap junction electrical, and neural and humoral receptor mediated agents (acetylcholine, endothelin, etc.). Smooth muscle in the gastrointestinal and urogenital tracts is regulated by the enteric nervous system and by peristaltic pacemaker cells -- the interstitial cells of Cajal.

Stretch, neural and humoral agents, and gap junction activity that depolarize the sarcolemma increase intracellular calcium. Extracellular calcium enters through L type calcium channels and intracellular calcium is released from stored calcium in the sarcoplasmic reticulum. Calcium release from the sarcoplasmic reticulum is through Ryanodine receptor channels (calcium sparks) by a redox process and inositol triphosphate receptor channels by the second messenger inositol triphosphate. The intracellular calcium binds with calmodulin which then binds and activates myosin-light chain kinase. The calcium-calmodulin-myosin light chain kinase complex phosphorylates the 20 kilodalton (kd) myosin light chains on amino acid residue-serine 19 to initiate contraction. The phosphorylation of the myosin light chains then allows the myosin ATPase to function. The thin filament associated proteins caldesmon and calponin are also believed to serve a function in contractility within smooth muscle. During contraction actin polymerization also occurs and it appears to be significant in the process.

Phosphorylation of the 20 kd myosin light chains correlates well with the shortening velocity of smooth muscle. During this period there is a rapid burst of energy utilization as measured by oxygen consumption. Within a few minutes of initiation the calcium level markedly decrease, 20 kd myosin light chains phosphorylation decreases, and energy utilization decreases and the muscle can relax, however there is a sustained maintenance of force in vascular smooth muscle. The sustained phase has been attributed to slowly cycling dephosphorylated myosin crossbridges termed latch-bridges and actin polymerization stiffening the cell. During contraction of muscle, rapidly cycling crossbridges form between activated actin and phosphorylated myosin generating force. During the sustained phase, phosphorylation levels decline and slow cycling dephosphorylated crossbridges act as latch bridges to contribute to maintaining the force at low energy costs. Other cell signalling pathways and protein kinases (Protein kinase C, ROCK kinase, Zip kinase, Focal adhesion kinases) have been implcated and actin polymerization dynamics plays a role in force maintenance. While myosin light chain phosphorylation correlates well with shortening velocity, other cell signalling pathways have been implicated in the development of force and maintenance of force. Notably the phosphorylation of specific tyrosine residues on the focal adhesion adapter protein-paxillin by specific tyrosine kinases has been demonstrated to be essential to force development and maintenance.

Phosphorylation of the 20kd myosin light chains is counteracted by a myosin light chain phosphatase that dephosphorylates the myosin light chains. Isolated preparations of vascular and visceral smooth muscle contract with depolarizing high potassium balanced saline generating a certain amount of contractile force. The same preparation stimulated in normal balanced saline with an agonist such as endothelin or serotonin will generate more contractile force. This increase in force is termed calcium sensitization. The myosin light chain phosphatase is inhibited to increase the gain or sensitivity of myosin light chain kinase to calcium. There are number of cell signalling pathways believed to regulate this decrease in myosin light chain phosphatase: a RhoA-Rock kinase pathway, a Protein kinase C-Protein kinase C potentiation inhibitor protein 17 (CPI-17) pathway, telokin, and a Zip kinase pathway. Further Rock kinase and Zip kinase have been implicated to directly phosphorylate the 20kd myosin light chains.

The relaxation of smooth muscle can be mediated by the endothelium-derived relaxing factor-nitric oxide, endothelial derived hyperpolarizing factor (either an endogenous cannabinoid, cytochrome P450 metabolite, or hydrogen peroxide), or prostacyclin (PGI2). Nitric oxide and PGI2 stimulate soluble guanylate cyclase and membrane bound adenylate cyclase, respectively. These cyclic nucleotides activate Protein Kinase G and Proten Kinase A and phosphorylate a number of proteins. The phosphorylation events lead to a decrease in intracelluar calcium (inhibit L type Calcium channels, inhibits IP3 receptor channels, stimulates sarcoplasmic reticulum Calcium pump ATPase), a decrease in the 20kd myosin light chain phosphorylation by altering calcium sensitization and increasing myosin light chain phosphatase activity, a stimulation of calcium sensitive potassium channels which hyperpolarize the cell, and the phosphorylation of amino acid residue serine 16 on the small heat shock protein (hsp20)by Protein Kinases A and G. The phosphorylation of hsp20 appears to alter actin and focal adhesion dynamics and actin-myosin interaction, and recent evidence indicates that hsp20 binding to 14-3-3 protein is envolved in this process. Hsp20 may also alter the affinity of phosphorylated myosin with actin and inhibit contractility by interfering with crossbridge formation. The endothelium derived hyperpolarizing factor stimulates calcium sensitive potassium channels and/or ATP sensitive potassium channels and stimulate potassium efflux which hyperpolarizes the cell and produces relaxation.GetAgrippa (talk) 15:38, 21 November 2007 (UTC)[reply]

This is a nice summary on the mechanical aspects of the relaxation-contraction mechanism but there is no discussion on the Latch-bridge state which is one of the most important principles for energy conservation in smooth muscle. This princple is the key to low fatiguability of smooth muscle. I can add this if no one feels incline to do so. SteveD 14th December 2008. 7:44 am. —Preceding unsigned comment added by 58.106.16.56 (talk) 20:45, 13 December 2008 (UTC)[reply]

That would be very nice to know, SteveD. Also, some people are interested in the exceptions to the rule that smooth muscle is involuntary. So, information concerning any conscious operation of the smooth muscle systems of the human body would be very useful for students, etc., to know. Thank you. (Contributions/124.180.255.210 (talk) 18:16, 15 June 2009 (UTC))[reply]

There is now a discussion of latch bridges. To my knowledge their aren't any volutary smooth muscles. All the smooth muscle sphincters are involuntary and skeletal muscle sphincters are voluntarily regulated. Smooth muscle in eyes, kidneys, arteries and veins, gut, bladder and reproductive tract, are involuntary. Smooth muscle in skin is also involuntary.GetAgrippa (talk) 01:34, 20 June 2009 (UTC)[reply]

Time to add references

I'm going to use the talk page as a sandbox while I gather references for this article. I will later format by Wikipedia standards. GetAgrippa (talk) 15:57, 14 December 2009 (UTC)[reply]

Contents of myofibrillar proteins in cardiac, skeletal, and smooth muscles. Murakami U, Uchida K. J Biochem. 1985 Jul;98(1):187-97.PMID: 4044549 [PubMed - indexed for MEDLINE]Related articles

The thin filaments of smooth muscles. Marston SB, Smith CW. J Muscle Res Cell Motil. 1985 Dec;6(6):669-708. Review.PMID: 3937845 [PubMed - indexed for MEDLINE]Related articles

Corkscrew-like shortening in single smooth muscle cells. Warshaw DM, McBride WJ, Work SS. Science. 1987 Jun 12;236(4807):1457-9.

Bennett, J. P., R. A. Cross, J. Kendrick-Jones, andA. G. Weeds. 1988. Spatial pattern of myosin phosphorylation in contracting smooth muscle PMID: 3109034 [PubMed - indexed for MEDLINE]

Membrane rafts and caveolae in cardiovascular signaling. Insel PA, Patel HH. Curr Opin Nephrol Hypertens. 2009 Jan;18(1):50-6. Review. PMID: 19077689 [PubMed - indexed for MEDLINE]

The latch-bridge hypothesis of smooth muscle contraction. Murphy RA, Rembold CM. Can J Physiol Pharmacol. 2005 Oct;83(10):857-64. Review. PMID: 16333357 [PubMed - indexed for MEDLINE]

Regulation of shortening velocity by cross-bridge phosphorylation in smooth muscle. Hai CM, Murphy RA. Am J Physiol. 1988 Jul;255(1 Pt 1):C86-94. PMID: 3389402 [PubMed - indexed for MEDLINE]

(Molluscan smooth muscle) Twitchin as a regulator of catch contraction in molluscan smooth muscle. Funabara D, Kanoh S, Siegman MJ, Butler TM, Hartshorne DJ, Watabe S. J Muscle Res Cell Motil. 2005;26(6-8):455-60. Review. PMID: 16453161 [PubMed - indexed for MEDLINE]

Molecular basis of the catch state in molluscan smooth muscles: a catchy challenge. Galler S.J Biol Chem. 1988 Dec 15;263(35):19166-73.

Sites phosphorylated in myosin light chain in contracting smooth muscle. Colburn JC, Michnoff CH, Hsu LC, Slaughter CA, Kamm KE, Stull JT. Department of Physiology, University of Texas Southwestern Medical Center, Dallas 75235. J Muscle Res Cell Motil. 2008;29(2-5):73-99. Epub 2008 Nov 28. Review. PMID: 19039672 [PubMed - indexed for MEDLINE]

Remember to add section on actin and myosin isoforms in smooth muscle!!!!! Add section of orientation of smooth muscle in various organs such as blood vessels,iris and ciliary body, respiratory tract, digestive tract layers, urinary tract, and reproductive tract-also differences in smooth muscle in these tissues. Perhaps a section for each with organization of smooth muscle, control, function, differences in contractile protein isoforms, receptors, cell signalling pathways, etc. Really bring article together with more info demonstrating the diversity of smooth muscle,Maybe a little biomechanics from Dobrin and Fung especially about viscoelasticity and length tension curve of smooth muscle compared to striated muscle (smooth can be stretched most, skeletal length tension curve then stiff cardiac curve due to titin isoforms-important in preload and Starling's law. Differences in receptors explain differences in response of skeletal blood vessels and coronary blood vessels dilate from sympathetic activation, unlike rest of vasculature which vasoconstricts. Importance of blood flow regulation in afferent and efferent arterioles of kidney glomerulus, mesangial cells, juxtaglomerular complex, then bladder smooth muscle section. Digestive tract section regulation of motiity by neuroendocrine factors, interstitial cells of Cajal, etc. Respiratory tract section tracheal, bronchial smooth muscle, section on asthma. Note how pulmonary arteries dilate with high pO2 whereas most constrict. Brain arteries sensitive to pH and carbon dioxide. Regulation of iris of eye section. Regulation of uterine contractions in sex and birth. Segment on errector pili smooth muscle of skin. Histology, Function and Regulation, Normal and Pathology to fit in WikiMedicine and Anatomy. GetAgrippa (talk) 05:23, 19 December 2009 (UTC)[reply]

Present Contents Contents [hide] 1 Function 2 Contraction and relaxation basics 3 Advances and Current Research in Contraction and Relaxation 4 Invertebrate smooth muscle 5 Control 6 Growth and rearrangement 7 Related diseases 8 References 9 See also 10 External links

Proposed Contents 1 Define, function and where present, nomenclature (single-unit vs multi-unit, phasic vs tonic, vascular vs visceral). 2 Contraction and relaxation. Biomechanical properties of smooth muscle tissues. 3 Digestive tract (these sections 3-7 will demonstrate diversity of smooth muscle and give info related to major systems) 4 Respiratory tract-Pulmonary arteries, bronchioles, tracheal, etc. 5 Excretory tract-juxtaglomerular complex-renin and tubuloglomerular feedback, bladder smooth muscle regulaton, etc. 6 Reproductive tract-Male (viagra, PDE inhibitors) and female (birth, hormones) 7 Other specialized areas: Brain-sensitivity to pH and hypercapnia, Skeletal and Coronary Arteries, Iris of Eye 8 Control 9 Growth and rearrangement 10 Related diseases 11 Invertebrate smooth muscle-regulation of latch state by twitchin. 12 See also 13 External links

Thanks

Thanks to all the editors who took my effort to expand this article and organized and expanded it. I still think some of my suggestions I posited above would be nice additions still. I added some references here but never incorporated so I'll try to do that. Regards. GetAgrippa (talk) 18:36, 24 January 2014 (UTC)[reply]

one of most — Preceding unsigned comment added by 49.146.214.228 (talk) 10:36, 1 July 2014 (UTC)[reply]

I'm going to use this as storage as I collect references.

Other tensile structures.

Isolated single smooth muscle cells have been observed contracting in a spiral corkscrew fashion, and isolated permeabilized smooth muscle cells adhered to glass (so contractile proteins allowed to internally contract) demonstrate zones of contractile protein interactions along the long axis as the cell contracts.

(Science, 236 (4807), 1457-9 1987 Jun 12 Corkscrew-like Shortening in Single Smooth Muscle Cells

D M Warshaw, W J McBride, S S Work PMID: 3109034 DOI: 10.1126/science.3109034)

*(J Cell Biol, 111 (6 Pt 1), 2463-73  Dec 1990

The Cytoskeletal and Contractile Apparatus of Smooth Muscle: Contraction Bands and Segmentation of the Contractile ElementsA Draeger 1 , W B Amos, M Ikebe, J V Small Affiliations expand PMID: 2277068 PMCID: PMC2116423 DOI: 10.1083/jcb.111.6.2463.

Adrenergic receptors (confounding sentence)

This sentence in the section 'External substances' is contradictory as regards adrenergic receptors in the smooth muscle. Blood vessel contraction is always caused by the smooth muscle of their walls, but the sentence starts saying they have alpha-1-adrenergic receptors but ends saying they have beta-adrenergic receptors. The sentence is: "For instance, most blood vessels respond to norepinephrine and epinephrine (from sympathetic stimulation or the adrenal medulla) by producing vasoconstriction (this response is mediated through alpha 1-adrenergic receptors). Blood vessels in skeletal muscle and cardiac muscle respond to these catecholamines producing vasodilation because the smooth muscle possess beta-adrenergic receptors." What does 'most blood vessels' mean here? Most blood vessels in the entire body? Or in the smooth muscle?-Miguelferig (talk) 12:04, 2 November 2014 (UTC)[reply]

Proposed merge of Single-unit smooth muscle into Smooth muscle

Small stub covered mostly on target page - the other type is multiunit another smaller stub without a target which would fit well into both items being covered on target page structure section Iztwoz (talk) 20:13, 7 April 2022 (UTC)[reply]

Support seems sensible and straightforward to have these covered on the same article.Tom (LT) (talk) 01:31, 22 April 2022 (UTC)[reply]