title: The potential role of unregulated autonomous bladder micromotions in urinary storage and voiding dysfunction; overactive bladder and detrusor underactivity.
abstract: The isolated bladder shows autonomous micromotions, which increase with bladder distension, generate sensory nerve activity, and are altered in models of urinary dysfunction. Intravesical pressure resulting from autonomous activity putatively reflects three key variables; the extent of micromotion initiation, distances over which micromotions propagate, and overall bladder tone. In vivo, these variables are subordinate to the efferent drive of the central nervous system. In the micturition cycle storage phase, efferent inhibition keeps autonomous activity generally at a low level, where it may signal 'state of fullness', whilst maintaining compliance. In the voiding phase, mass efferent excitation elicits generalised contraction (global motility initiation). In lower urinary tract dysfunction, efferent control of the bladder can be impaired, for example due to peripheral 'patchy' denervation. In this case, loss of efferent inhibition may enable unregulated micromotility, and afferent stimulation, predisposing to urinary urgency. If denervation is relatively slight, the detrimental impact on voiding may be low, as the adjacent innervated areas may be able to initiate micromotility synchronous with the efferent nerve drive, so that even denervated areas can contribute to the voiding contraction. This would become increasingly inefficient the more severe the denervation, such that ability of triggered micromotility to propagate sufficiently to engage the denervated areas in voiding declines, so the voiding contraction increasingly develops the characteristics of underactivity. In summary, reduced peripheral coverage by the dual efferent innervation (inhibitory and excitatory) impairs regulation of micromotility initiation and propagation, potentially allowing emergence of overactive bladder and, with progression, detrusor underactivity.
authors.affiliation: School of Clinical Sciences, Pharmacology and Neuroscience, University of Bristol, Bristol, UK.|Bristol Urological Institute, Southmead Hospital, University of West of England, Bristol, UK.
authors.forename: Marcus J
authors.initials: MJ
authors.lastname: Drake
authors.affiliation: University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Anthony
authors.initials: A
authors.lastname: Kanai
authors.affiliation: Bristol Urological Institute, Southmead Hospital, University of West of England, Bristol, UK.
authors.forename: Dominika A
authors.initials: DA
authors.lastname: Bijos
authors.affiliation: University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Youko
authors.initials: Y
authors.lastname: Ikeda
authors.affiliation: University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: Irina
authors.initials: I
authors.lastname: Zabbarova
authors.affiliation: Bristol Urological Institute, Southmead Hospital, University of West of England, Bristol, UK.|School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, UK.
authors.forename: Bahareh
authors.initials: B
authors.lastname: Vahabi
authors.affiliation: University of West of England, Bristol, UK.
authors.forename: Christopher H
authors.initials: CH
authors.lastname: Fry
mesh_terms: D006801:Humans; D011312:Pressure; D001743:Urinary Bladder / Q000503:physiopathology*; D001745:Urinary Bladder Diseases / Q000503:physiopathology*; D053201:Urinary Bladder, Overactive / Q000503:physiopathology; D014555:Urination Disorders / Q000503:physiopathology*; D014556:Urine; D014563:Urodynamics
keywords: 
  LUTS
  ; detrusor overactivity; detrusor underactivity; micromotions; overactive bladder; urodynamics