The physiological function of lower urinary tract smooth muscle

Fry, Christopher; Meng, En; Young, John S.

doi:10.1016/j.autneu.2009.10.006

Cited by 87 publications

(66 citation statements)

References 139 publications

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“…In the urinary bladder, treatment with selective L-VDCC inhibitors (e.g., nifedipine) strongly inhibits or abolishes spontaneous detrusor activity, indicating that detrusor contractility depends on the influx of extracellular Ca 2ϩ (26,29). Although SR Ca 2ϩ stores are presumed to contribute to cholinergic detrusor contractions (3,20), the role …”

Section: Morphology Of Mucosal Stripsmentioning

confidence: 99%

Unique properties of muscularis mucosae smooth muscle in guinea pig urinary bladder

Heppner¹,

Layne²,

Pearson³

et al. 2011

American Journal of Physiology-Regulatory, Integrative and Comp

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The muscularis mucosae, a type of smooth muscle located between the urothelium and the urinary bladder detrusor, has been described, although its properties and role in bladder function have not been characterized. Here, using mucosal tissue strips isolated from guinea pig urinary bladders, we identified spontaneous phasic contractions (SPCs) that appear to originate in the muscularis mucosae. This smooth muscle layer exhibited Ca 2ϩ waves and flashes, but localized Ca 2ϩ events (Ca 2ϩ sparks, purinergic receptor-mediated transients) were not detected. Ca 2ϩ flashes, often in bursts, occurred with a frequency (ϳ5.7/min) similar to that of SPCs (ϳ4/min), suggesting that SPCs are triggered by bursts of Ca 2ϩ flashes. The force generated by a single mucosal SPC represented the maximal force of the strip, whereas a single detrusor SPC was ϳ3% of maximal force of the detrusor strip. Electrical field stimulation (0.5-50 Hz) evoked force transients in isolated detrusor and mucosal strips. Inhibition of cholinergic receptors significantly decreased force in detrusor and mucosal strips (at higher frequencies). Concurrent inhibition of purinergic and cholinergic receptors nearly abolished evoked responses in detrusor and mucosae. Mucosal SPCs were unaffected by blocking smallconductance Ca 2ϩ -activated K ϩ (SK) channels with apamin and were unchanged by blocking large-conductance Ca 2ϩ -activated K ϩ (BK) channels with iberiotoxin (IbTX), indicating that SK and BK channels play a much smaller role in regulating muscularis mucosae SPCs than they do in regulating detrusor SPCs. Consistent with this, BK channel current density in myocytes from muscularis mucosae was ϳ20% of that in detrusor myocytes. These findings indicate that the muscularis mucosae in guinea pig represents a second smooth muscle compartment that is physiologically and pharmacologically distinct from the detrusor and may contribute to the overall contractile properties of the urinary bladder. calcium imaging; large-conductance calcium-activated potassium channel; potassium channels; calcium flashes; spontaneous phasic contractions THE URINARY BLADDER is a hollow, muscular organ that serves two functions: urine storage and elimination. The bladder wall is composed of detrusor smooth muscle, which accounts for a large fraction of the bladder mass, and a layer of transitional epithelial cells known as the urothelium, which lines the luminal surface of the urinary bladder. The detrusor smooth muscle has been extensively characterized and is clearly responsible for the majority of the contractile properties of the urinary bladder (1, 69). The urothelium, which was originally thought to simply act as a passive, impermeable barrier that prevents the movement of solutes from the urine into the bloodstream, is now recognized to possess a broad range of sensory and signal transduction functions that greatly influence bladder physiology (for a review, see Ref. 5).The detrusor exhibits two primary modes of contractile behavior: nerve-evoked contractions and spontaneo...

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Section: Morphology Of Mucosal Stripsmentioning

confidence: 99%

Unique properties of muscularis mucosae smooth muscle in guinea pig urinary bladder

Heppner¹,

Layne²,

Pearson³

et al. 2011

American Journal of Physiology-Regulatory, Integrative and Comp

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“…We believe that the region between the bladder neck and duct openings where we observed regular inherent contractions forms part of the IUS, since we by histochemistry identified an IUS consisting of an inner longitudinal layer and an outer circular layer in the region between neck and duct openings. The spontaneous electrical and mechanical activity of this region contributes to overall muscular tone 24, 28.…”

Section: Discussionmentioning

confidence: 99%

Prostaglandin D₂ effects and DP₁/DP₂ receptor distribution in guinea pig urinary bladder out‐flow region

Guan

Svennersten

Verdier

et al. 2016

J Cellular Molecular Medi

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The proximal urethra and urinary bladder trigone play important roles in continence. We have previously shown that PGD 2 is released from guinea pig bladder urothelium/suburothelium and can inhibit detrusor contractile responses. We presently wished to investigate PGD 2 actions in guinea pig out‐flow region and the distribution of DP 1/DP 2 receptors. The effects of PGD 2 on urothelium‐intact trigone and proximal urethra contractility were studied in organ bath experiments. Expression of DP 1/DP 2 receptor proteins was analysed by western blot. Immunohistochemistry was used to identify distribution of DP 1/DP 2 receptors. PGD 2 in a dose‐dependent manner inhibited trigone contractions induced by electrical field stimulation (EFS) and inhibited spontaneous contractions of the proximal urethra. PGD 2 was equally (trigone) or slightly less potent (urethra) compared with PGE 2. Expression of DP 1 and DP 2 receptors was found in male guinea pig bladder trigone, neck and proximal urethra. In the trigone and proximal urethra, DP 1 receptors were found on the membrane of smooth muscle cells and weak immunoreactivty was observed in the urothelium. DP 2 receptors were distributed more widespread, weakly and evenly in the urothelium and smooth muscles. Inhibitory effects by PGD 2 on motor activity of guinea pig trigone and proximal urethra are consistent with finding DP 1 and DP 2 receptors located in the urothelium and smooth muscle cells of the trigone and proximal urethra, and PGD 2 may therefore be a modulator of the bladder out‐flow region, possibly having a function in regulation of micturition and a role in overactive bladder syndrome.

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“…При этом возможно также объединение отдельных потенциалов в группы в виде вспышек активности, которе ассоциируются с последующей контрактурой [6,7,8]. Описанная спонтанная электрическая активность наблюдается также в изолированном мочевом пузыре, в его мышечных препаратах или даже в единичных клетках [9,10].…”

Section: удк 61273+612468unclassified

“…Мочевой пузырь большую часть времени функционального цикла ведет себя как орган кумуляции мочи, при этом в различных областях мышечного слоя наблюдается аналогичный электрический базовый ритм. В этом же временном интервале уретра контрактирует препятствуя утечке мочи и создавая тем самым условия для продолжительного мышечного тонуса [6,13]. Фаза опорожнения мочевого пузыря, обеспечиваемая синхронизацией пейсмекеров детрузор (мышечные слои) для формирования перистальтики органа, сопровождается кратковременной релаксацией мышц уретры [8,14].…”

Section: удк 61273+612468unclassified

“…Возможно, правый мочеточник в связи с наличием более устойчивых показателей активности (перерезка органа не влияет на их значения) способен компенсировать отсутствие влияния левого (активного) мочеточника. Уретра же, в отличие от мочеточников, являясь более пассивным и дистально расположенным по отношению к мочевому пузырю органом, полностью сама зависит от сменяющих друг друга его функциональных фаз [6,14] и поэтому отсоединение уретры от мочевого пузыря не оказывает определенного влияния на его активность.…”

Section: рис 2 влияние последовательных перерезок мочеточников на аunclassified

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The electrical activity of the bladder after isolation

Kazaryan¹,

Chibukhchyan²,

Mkrtchyan³

2017

PMSE

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Как известно, многие висцеральные органы характеризуются спонтанно генерируемыми электрическими разрядами, которые отмечаются в различных мышечных слоях [1,2]. В верхнем мочевом тракте именно мочеточники, являющиеся парными органами, обеспечивают проведение мочи к мочевому пузырю. Условия для продвижения мочи вдоль мочеточников создаются при возникновении спонтанной контрактуры, сопряженной с пейсмекерной электрической активностью. Пейсмекерный ритмогенез возникает в проксимольной зоне почечной лоханки и впоследствии, координируясь, распространяетcя вдоль мочеточника [2,3].Если к особенностям электрической спонтанной активности данного органа можно отнести строгую ритмичность [4,5], то в мышечных слоях стенок мочевого пузыря регистрируются сопряженные со спайковой пейсмекерной активностью нераспространяющиеся микроконтрактуры. При этом возможно также объединение отдельных потенциалов в группы в виде вспышек активности, которе ассоциируются с

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The physiological function of lower urinary tract smooth muscle

Cited by 87 publications

References 139 publications

Unique properties of muscularis mucosae smooth muscle in guinea pig urinary bladder

Unique properties of muscularis mucosae smooth muscle in guinea pig urinary bladder

Prostaglandin D₂ effects and DP₁/DP₂ receptor distribution in guinea pig urinary bladder out‐flow region

The electrical activity of the bladder after isolation

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The physiological function of lower urinary tract smooth muscle

Cited by 87 publications

References 139 publications

Unique properties of muscularis mucosae smooth muscle in guinea pig urinary bladder

Unique properties of muscularis mucosae smooth muscle in guinea pig urinary bladder

Prostaglandin D2 effects and DP1/DP2 receptor distribution in guinea pig urinary bladder out‐flow region

The electrical activity of the bladder after isolation

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Prostaglandin D₂ effects and DP₁/DP₂ receptor distribution in guinea pig urinary bladder out‐flow region