title: Bladder filling attenuates spinal cord nociceptive reflexes in humans.
abstract: OBJECTIVE
  To examine the viscerosomatic interaction between bladder afferents and somatic nociception we evaluated the effect of bladder filling on the nociceptive withdrawal reflex (NWR) in 21 healthy subjects.
  
  
  METHODS
  NWR was evoked in the lower and upper limbs by stimulating the sural and index finger digital nerves, respectively, while simultaneously recording EMG activity in the biceps femoris and biceps brachialis. NWR pain-related perception was quantified on a 10-point pain scale. Bladder filling was evaluated with suprapubic bladder sonography. Subjects were examined during empty bladder, medium and high level of bladder filling sessions.
  
  
  RESULTS
  NWR magnitude in both upper and lower limbs and perceived pain for the upper limb were significantly decreased at higher levels of bladder filling compared to empty bladder sessions.
  
  
  CONCLUSIONS
  Reduced NWR magnitude in both upper and lower limbs during bladder filling strongly indicates that bladder control and nociception share common modulatory descending pathways. Bladder afferents may activate these pathways to suppress the micturition reflex, but they may also inhibit spinal reflexes to maintain continence during pain stimuli.
  
  
  CONCLUSIONS
  The effect of bladder filling on the NWR may represent a useful tool to investigate interactions between the neural pathways controlling the bladder and pain.
authors.affiliation: Unit of Neurorehabilitation, Department of Medical-Surgical Sciences and Biotechnologies, Sapienza University of Rome, ICOT, Latina, Italy. Electronic address: mariano.serrao@uniroma1.it.
authors.forename: Mariano
authors.initials: M
authors.lastname: Serrao
authors.affiliation: Unit of Neurorehabilitation, Department of Medical-Surgical Sciences and Biotechnologies, Sapienza University of Rome, ICOT, Latina, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Cortese
authors.affiliation: Unit of Neurorehabilitation, Department of Medical-Surgical Sciences and Biotechnologies, Sapienza University of Rome, ICOT, Latina, Italy.
authors.forename: Gaia
authors.initials: G
authors.lastname: Fragiotta
authors.affiliation: Unit of Urology, Department of Medical-Surgical Sciences and Biotechnologies, Sapienza University of Rome, ICOT, Latina, Italy.
authors.forename: Antonio Luigi
authors.initials: AL
authors.lastname: Pastore
authors.affiliation: Unit of Urology, Department of Medical-Surgical Sciences and Biotechnologies, Sapienza University of Rome, ICOT, Latina, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Palleschi
authors.affiliation: G.B. Bietti Eye Foundation-IRCCS, Department of Neurophysiology of Vision and Neurophthalmology, Rome, Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Coppola
authors.affiliation: Unit of Urology, Department of Medical-Surgical Sciences and Biotechnologies, Sapienza University of Rome, ICOT, Latina, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Carbone
authors.affiliation: IRCCS Neuromed, Pozzilli, IS, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Pierelli
mesh_terms: D000328:Adult; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D018482:Muscle, Skeletal / Q000503:physiopathology; D059225:Nociception / Q000502:physiology*; D010146:Pain / Q000503:physiopathology*; D010147:Pain Measurement; D012018:Reflex / Q000502:physiology*; D013116:Spinal Cord / Q000502:physiology*; D001743:Urinary Bladder / Q000502:physiology*
keywords: Bladder filling; Descending control; Nociception; Nociceptive withdrawal reflex; Viscero-somatic interaction