A study was performed to determine the in vitro response of the longitudinal smooth muscle layer (conjoined longitudinal coat) of the human and canal to cholinergic and adrenergic stimulation, and to compare this with similar features of the internal anal sphincter (IAS) and rectal smooth muscle. Tissue was obtained from abdominoperineal and anterior resection specimens, and strips of muscle mounted for isometric tension recording in superfusion organ baths. Both conjoined longitudinal coat and IAS strips generated and maintained spontaneous myogenic tension (mean(s.e.m.) 0.10(0.01) and 0.48(0.04) g per mg tissue respectively), whereas equivalent rectal smooth muscle did not. Stimulation of muscarinic (cholinergic) receptors caused contraction of strips from the conjoined longitudinal coat and rectal smooth muscle layers in a dose-dependent manner (10(-7)-10(-4) mol/l); however, IAS strips relaxed (10(-6)-10(-4) mol/l). Activation of alpha-adrenergic receptors in conjoined longitudinal coat and IAS strips produced concentration-dependent contraction (10(-7)-10(-4) mol/l). In comparison, rectal smooth muscle relaxed. All muscle layers relaxed in response to beta-adrenoceptor stimulation. These data indicate that in the anal canal both the conjoined longitudinal coat and IAS are specialized sphincteric smooth muscles.
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http://dx.doi.org/10.1002/bjs.1800801041 | DOI Listing |
ACS Biomater Sci Eng
January 2025
Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, P.R. China.
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View Article and Find Full Text PDFWorld J Biol Psychiatry
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Division of Genetics, Department of Cell and Molecular Biology and Microbiology, Faculty of Biological Science and Technology, University of Isfahan, Isfahan, Iran.
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Vet Sci
January 2025
Department of Veterinary Medicine, University of Perugia, Via San Costanzo 4, 06126 Perugia, Italy.
Ghrelin (GhRL) is an orexigenic hormone influenced by nutritional state. It plays a role in skin repair and diseases, though little information exists regarding its function in this organ. GhRL and its receptor were investigated in the skin of sheep under different feeding conditions to explore GhRL system presence and possible modifications due to diet.
View Article and Find Full Text PDFMetabolites
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The College of Nursing, Zhejiang Chinese Medical University, Hangzhou 310053, China.
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View Article and Find Full Text PDFBiomimetics (Basel)
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School of Engineering, University of Kent, Canterbury CT2 7NZ, UK.
Pneumatic artificial muscles (PAMs) are flexible actuators that can be contracted or expanded by applying air pressure. They are used in robotics, prosthetics, and other applications requiring flexible and compliant actuation. PAMs are basically designed to mimic the function of biological muscles, providing a high force-to-weight ratio and smooth, lifelike movement.
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