Contractile properties of the proximal urethra and bladder in female pig: Morphology and function

Pel, J.J.M.; Asselt, Els van; Mastrigt, Ron van

doi:10.1002/nau.20156

Cited by 10 publications

(8 citation statements)

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“…Mean curv factor (0.371 ± 0.144) is within the range of 0.1–0.5 normally found in smooth (Stephens et al, 1969; Gordon and Siegman, 1971; Uvelius, 1977; Moriya and Miyazaki, 1985; Menzel et al, 2017; Tomalka et al, 2017) and skeletal muscles (Siebert et al, 2015). The average v max of 0.071 ± 0.017 L 0 / s is within the range of values of 0.04–0.35 L 0 / s observed in visceral smooth muscles from the pig (Uvelius, 1977; Minekus and van Mastrigt, 2001; Pel et al, 2006; Menzel et al, 2017; Tomalka et al, 2017).…”

Section: Discussionsupporting

confidence: 74%

“…At the same time the urethra, which on the other hand has been shown to contain tonic smooth muscle fibers (Hypolite et al, 2001; Pel et al, 2006), relaxes during micturition, and contracts afterward, thereby initiating a new filling process. Unlike the stomach, which autonomously stores, digests, and transports its content, the urinary bladder is (as a complete organ) either in the process of being filled or being emptied.…”

Section: Discussionmentioning

confidence: 99%

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Locational and Directional Dependencies of Smooth Muscle Properties in Pig Urinary Bladder

et al. 2019

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The urinary bladder is a distensible hollow muscular organ, which allows huge changes in size during absorption, storage and micturition. Pathological alterations of biomechanical properties can lead to bladder dysfunction and loss in quality of life. To understand and treat bladder diseases, the mechanisms of the healthy urinary bladder need to be determined. Thus, a series of studies focused on the detrusor muscle, a layer of urinary bladder made of smooth muscle fibers arranged in longitudinal and circumferential orientation. However, little is known about whether its active muscle properties differ depending on location and direction. This study aimed to investigate the porcine bladder for heterogeneous (six different locations) and anisotropic (longitudinal vs. circumferential) contractile properties including the force-length-(FLR) and force-velocity-relationship (FVR). Therefore, smooth muscle tissue strips with longitudinal and circumferential direction have been prepared from different bladder locations (apex dorsal, apex ventral, body dorsal, body ventral, trigone dorsal, trigone ventral). FLR and FVR have been determined by a series of isometric and isotonic contractions. Additionally, histological analyses were conducted to determine smooth muscle content and fiber orientation. Mechanical and histological examinations were carried out on 94 and 36 samples, respectively. The results showed that maximum active stress (pact) of the bladder strips was higher in the longitudinal compared to the circumferential direction. This is in line with our histological investigation showing a higher smooth muscle content in the bladder strips in the longitudinal direction. However, normalization of maximum strip force by the cross-sectional area (CSA) of smooth muscle fibers yielded similar smooth muscle maximum stresses (165.4 ± 29.6 kPa), independent of strip direction. Active muscle properties (FLR, FVR) showed no locational differences. The trigone exhibited higher passive stress (ppass) than the body. Moreover, the bladder exhibited greater ppass in the longitudinal than circumferential direction which might be attributed to its microstructure (more longitudinal arrangement of muscle fibers). This study provides a valuable dataset for the development of constitutive computational models of the healthy urinary bladder. These models are relevant from a medical standpoint, as they contribute to the basic understanding of the function of the bladder in health and disease.

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Section: Discussionsupporting

confidence: 74%

Section: Discussionmentioning

confidence: 99%

Locational and Directional Dependencies of Smooth Muscle Properties in Pig Urinary Bladder

et al. 2019

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“…Furthermore, the symptoms associated with uninhibited contractions that occur in patients with overactive bladder are considered to occur, in part, through stimulation of receptor pathways other than the muscarinic system 6 . The influence of different receptor systems within the U&LP has been of particular interest, specifically their impact on the spontaneous contractile activity that is known to occur during the filling phase 49,50 . These contractions may also play a role in the regulation of tone and the overall continence mechanisms, as previously hypothesised in the literature 50 .…”

Section: Discussionmentioning

confidence: 99%

“…The influence of different receptor systems within the U&LP has been of particular interest, specifically their impact on the spontaneous contractile activity that is known to occur during the filling phase 49,50 . These contractions may also play a role in the regulation of tone and the overall continence mechanisms, as previously hypothesised in the literature 50 .…”

Section: Discussionmentioning

confidence: 99%

Alterations in histamine responses between juvenile and adult urinary bladder urothelium, lamina propria and detrusor tissues

Štromberga

Chess-Williams

Moro

2020

Sci Rep

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Russ chess-Williams & christian Moro * Inflammatory mediators may have a role in various lower urinary tract disorders. Histamine is known to induce significant increases in both the tension and frequency of spontaneous phasic contractions in both urothelium with lamina propria (U&LP) and detrusor muscle via the activation of H1 receptor in juvenile animal models. However, it is unclear whether age affects these contractile responses to histamine. This study assessed the histamine receptor subtypes mediating contraction in juvenile and adult porcine bladders and compared the urothelium with lamina propria and detrusor responses to histamine. Isolated tissue bath studies were conducted using strips of porcine U&LP and detrusor obtained from juvenile (6 months) and adult (3 years) animals exposed to histamine receptor agonists and antagonists. Treatment with histamine (100 µM) in U&LP of juvenile animals caused increases in baseline tension by 47.84 ± 6.52 mN/g (p < 0.001, n = 51) and by 50.76 ± 4.10 mN/g (p < 0.001, n = 55) in adult animals. Furthermore, the frequency of spontaneous phasic contractions was significantly enhanced in response to histamine in U&LP of both juvenile and adult tissues (p < 0.001 for both age groups). Treatment with an H2 agonist in U&LP of juvenile animals decreased baseline tension by 13.97 ± 3.45 mN/g (n = 12, p < 0.05), but had no effect in adult animals. Inhibition of H1 receptors resulted in significantly reduced contractile responses of U&LP and detrusor to histamine in both juvenile and adult animals (p < 0.05). Treatment with an H2 receptor antagonist significantly enhanced contractions in juvenile preparations (n = 10, p < 0.05) but had no effect in adult preparations (n = 8). In detrusor, treatment with histamine (100 µM) in juvenile tissues showed a significantly higher increase in baseline tension of 19.10 ± 4.92 mN/g (n = 51) when compared to adult tissues exhibiting increases of 8.21 ± 0.89 mN/g (n = 56, p < 0.05). The increases in the baseline tension were significantly inhibited by the presence of H1 receptor antagonists in both juvenile and adult detrusor preparations. Treatment with either the H2 receptor antagonist or agonist in detrusor had no effect on both juvenile and adult tissues. Therefore, the histamine receptor system may play an essential role in the maintenance of bladder function or in bladder dysfunction observed in some lower urinary tract disorders. Normal bladder function deteriorates throughout adult life, age appearing to have a direct effect on bladder sensation, contractility and the ability to postpone voiding 1. Ageing is associated with several changes that occur in the urinary bladder, such as a reduction in bladder capacity 2 and an increase in bladder sensitisation 3. It is also linked with marked increases in the prevalence of lower urinary tract symptoms, such as urinary frequency, voiding difficulties, decreased bladder contractions (as seen in underactive bladder) or uninhibited bladder contractions (as seen in overactive bladder) 1. Urin...

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“…Typically, muscle tissue is mounted along the muscle direction to a force-measuring device, while muscle activation is initiated through electrical or pharmacological stimulation. Thereby, biomechanical properties of smooth muscles in uniaxial experiments have been examined on tissue specimens, dissected from the bladder [8,17,25,28,30,32,38,39,42,45,[54][55][56][57][58], the stomach [18,23,34,49], the intestine [2,3,13,16,26,29,31], the trachea [7,35,47,48,51], or from blood vessels [11,12,19,36,37,60].…”

Section: Introductionmentioning

confidence: 99%

Influence of layer separation on the determination of stomach smooth muscle properties

Borsdorf

Böl

Siebert

2021

Pflugers Arch - Eur J Physiol

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Uniaxial tensile experiments are a standard method to determine the contractile properties of smooth muscles. Smooth muscle strips from organs of the urogenital and gastrointestinal tract contain multiple muscle layers with different muscle fiber orientations, which are frequently not separated for the experiments. During strip activation, these muscle fibers contract in deviant orientations from the force-measuring axis, affecting the biomechanical characteristics of the tissue strips. This study aimed to investigate the influence of muscle layer separation on the determination of smooth muscle properties. Smooth muscle strips, consisting of longitudinal and circumferential muscle layers (whole-muscle strips [WMS]), and smooth muscle strips, consisting of only the circumferential muscle layer (separated layer strips [SLS]), have been prepared from the fundus of the porcine stomach. Strips were mounted with muscle fibers of the circumferential layer inline with the force-measuring axis of the uniaxial testing setup. The force–length (FLR) and force–velocity relationships (FVR) were determined through a series of isometric and isotonic contractions, respectively. Muscle layer separation revealed no changes in the FLR. However, the SLS exhibited a higher maximal shortening velocity and a lower curvature factor than WMS. During WMS activation, the transversally oriented muscle fibers of the longitudinal layer shortened, resulting in a narrowing of this layer. Expecting volume constancy of muscle tissue, this narrowing leads to a lengthening of the longitudinal layer, which counteracted the shortening of the circumferential layer during isotonic contractions. Consequently, the shortening velocities of the WMS were decreased significantly. This effect was stronger at high shortening velocities.

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Contractile properties of the proximal urethra and bladder in female pig: Morphology and function

Abstract: Differences in contractility found between urethra and bladder may be ascribed to the presence of striated muscle in the proximal urethra. The regulation of tone and spontaneous contractions may be part of the continence mechanism in the female pig urinary tract.

Cited by 10 publications

References 30 publications

Locational and Directional Dependencies of Smooth Muscle Properties in Pig Urinary Bladder

Locational and Directional Dependencies of Smooth Muscle Properties in Pig Urinary Bladder

Alterations in histamine responses between juvenile and adult urinary bladder urothelium, lamina propria and detrusor tissues

Influence of layer separation on the determination of stomach smooth muscle properties

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