The autonomous bladder: a view of the origin of bladder overactivity and sensory urge

Gillespie, James

doi:10.1111/j.1464-410x.2003.04667.x

Cited by 150 publications

(213 citation statements)

References 29 publications

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“…They occur normally during bladder filling and may contribute to maintaining blood flow during periods of increased intravesicle pressure as would occur during bladder filling; alternatively, they may provide information on bladder fullness (22). Histological stains and Ca 2ϩ imaging show a thin layer of smooth muscle-the muscularis mucosae-composed of connecting sheets and bundles that suggests synchronization over a large area.…”

Section: Perspectives and Significancementioning

confidence: 99%

“…These small, spontaneous nonvoiding contractions, which occur in parts of the bladder wall, have also been called micromotions (11) or microtransients (16). These events may be important during the filling phase, playing a role in adjusting the length of smooth muscle fibers in response to filling (7) or communicating information on bladder fullness (11,16,22). Because the contractile force of muscularis mucosae contractions is ϳ40 times less than that of the detrusor, these events would be expected to contribute minimally to micturition.…”

Section: R359mentioning

confidence: 99%

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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: Perspectives and Significancementioning

confidence: 99%

Section: R359mentioning

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

View full text Add to dashboard Cite

show abstract

“…3 Despite this, the bladder develops tone during filling and also exhibits non-synchronized local contractions and relaxations. [4][5][6] This is believed to be caused by a myogenic contractile activity that may be reinforced by release of mediators from non-neuronal (urothelium, lamina propria, other structures) as well as neuronal sources. 4,5 The normal stimulus for activation of the micturition reflex is considered to be distension of the bladder, initiating activity in ''in series''-coupled, low-threshold mechanoreceptive afferents (see below).…”

Section: Introductionmentioning

confidence: 99%

“…[4][5][6] This is believed to be caused by a myogenic contractile activity that may be reinforced by release of mediators from non-neuronal (urothelium, lamina propria, other structures) as well as neuronal sources. 4,5 The normal stimulus for activation of the micturition reflex is considered to be distension of the bladder, initiating activity in ''in series''-coupled, low-threshold mechanoreceptive afferents (see below). There are reasons to believe that the spontaneous contractile, phasic activity of the detrusor smooth muscle during filling can generate afferent input (''afferent noise''), and that in pathologic conditions, for example, OAB/DO, this activity may contribute to these disorders.…”

Section: Introductionmentioning

confidence: 99%

Detrusor myocyte activity and afferent signaling

Andersson

2009

Neurourology and Urodynamics

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Aims: To discuss (1) mechanisms involved in the generation and control of myocyte contractions and consequent afferent nerve activity and (2) these mechanisms as targets for drugs aimed for treatment of overactive bladder (OAB) symptoms and detrusor overactivity (DO). Methods: Literature review of myocyte activation, bladder afferent nerves, mediators in the bladder, and translational aspects of the findings. Results: During bladder filling, there is normally no parasympathetic outflow from the spinal cord. Despite this, the bladder develops tone during filling and also exhibits non-synchronized local contractions and relaxations that are caused by a basal myogenic mechanical activity that may be reinforced by release of, for example, acetylcholine from non-neuronal and/or neuronal sources or local mediators, such as prostaglandins and endothelins. It is suggested that these spontaneous contractions are able to generate activity in afferent nerves (''afferent noise'') that may contribute to DO and OAB. Conclusions: Spontaneous bladder myocyte contractions and factors that are able to modulate them, as well as the consequent afferent nerve activity, may be targets for drugs meant for treatment of OAB/DO. Neurourol.

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“…Bladder hypertrophy might also be an aetiological factor in the changing ACA post-SCI, otherwise alterations in ACA might facilitate the emergence of axonal sprouting and the recovery of voiding. As suggested by others, increased ACA could be an endogenous mechanism to increase afferent signalling in an attempt to re-establish voiding reflexes [6,13]. It is known that bladder-wall compliance may decrease in bladders from chronic SCI patients [14,15].…”

Section: Discussionmentioning

confidence: 97%

The Loss and Progressive Recovery of Voiding after Spinal Cord Interruption in Rats is Associated with Simultaneous Changes in Autonomous Contractile Bladder Activity

et al. 2009

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Background: Autonomous contractile activity (ACA) is a well-known phenomenon in isolated bladders from different species and seems to be important in the physiology of both normal and dysfunctional voiding. Objective: To determine whether ACA is changed in bladders from paraplegic rats at different periods post-spinal cord injury (post-SCI). Design, setting, and participants: ACA was studied in bladders (at least six per group) from normal and paraplegic female Wister rats at different times post-SCI (2 h, 24 h, 1 wk, and 3 wk). A group of normal rats was used as a control group. For measurements bladders were incubated in organ baths under standardised conditions. Measurements: ACA was measured as pressure change, which was defined as either a transient change or a spiked change according to its characteristics. The effects of intravesical volume load and muscarinic agonists were studied. Results and limitations: Following spinal cord injury (SCI) a clear evolution in ACA was observed. In bladders from SCI rats in the acute areflexive voiding phase (1 wk post-SCI), we observed decreased ACA associated with a highly increased compliance and a changed response to muscarinic agonists. ACA in bladders from SCI rats with renewed voiding reflexes (3 wk post-SCI) was increased, together with a moderately increased compliance and a (moderately) changed response to muscarinic agonists. Conclusions: From these observations it is apparent that SCI leads to alterations in the behaviour and muscarinic response of ACA in the isolated bladder. These changes in ACA may play an important role in the pathophysiology of overactive bladder disease (OAB), and interacting with changed ACA might be promising in the search for newer treatments for OAB.

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The autonomous bladder: a view of the origin of bladder overactivity and sensory urge

Cited by 150 publications

References 29 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

Detrusor myocyte activity and afferent signaling

The Loss and Progressive Recovery of Voiding after Spinal Cord Interruption in Rats is Associated with Simultaneous Changes in Autonomous Contractile Bladder Activity

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