title: Modulation of the rat micturition reflex with transcutaneous ultrasound.
abstract: BACKGROUND
  Low intensity focused ultrasound has recently been identified as a novel method of stimulating targeted neurons. We hypothesized that ultrasound stimulation of the posterior tibial nerve would inhibit bladder contractions in an established rat model of rhythmic bladder contractions.
  
  
  METHODS
  Cyclical detrusor contractions were initiated by placing a transurethral catheter in female rats and infusing saline into the bladder. Transcutaneous ultrasound pulses were then delivered to the lower extremity of a rat (overlying the posterior tibial nerve) using a single element spherically focused 250 kHz transducer. Sixty-three cycles were repeated at 2 kHz for 300 ms at peak negative pressure of 900 kPa pulsed at 0.5 Hz.
  
  
  RESULTS
  We report successful suppression of bladder contractions using ultrasound stimulation in 10 animals. The average latency between the initiation of ultrasound and suppression of bladder contractions was 3 min 23 s (±51 s), the average time of contraction suppression was 13 min and 50 s (±2 min 25 s) and the average time from the end of ultrasound to return of contractions was 9 min 37 s (±2 min and 30 s).
  
  
  CONCLUSIONS
  In this work, we demonstrate the ability of targeted transcutaneous ultrasound to inhibit rhythmic bladder contractions in anesthetized rats. Due to its non-invasive nature and ease of application, we believe ultrasound mediated suppression of the micturition reflex is potentially an ideal outpatient treatment of overactive bladder and dysfunctional elimination.
authors.affiliation: Children's National Medical Center, Washington, District of Columbia.
authors.forename: Daniel P
authors.identifier: http://orcid.org/0000-0003-1436-2152
authors.initials: DP
authors.lastname: Casella
authors.affiliation: Vanderbilt University Medical Center, Nashville, Tennessee.
authors.forename: Anne G
authors.initials: AG
authors.lastname: Dudley
authors.affiliation: Vanderbilt University Medical Center, Nashville, Tennessee.
authors.forename: Douglass B
authors.initials: DB
authors.lastname: Clayton
authors.affiliation: Vanderbilt University Medical Center, Nashville, Tennessee.
authors.forename: John C
authors.initials: JC
authors.lastname: Pope
authors.affiliation: Vanderbilt University Medical Center, Nashville, Tennessee.
authors.forename: Stacy T
authors.initials: ST
authors.lastname: Tanaka
authors.affiliation: Vanderbilt University Medical Center, Nashville, Tennessee.
authors.forename: John
authors.initials: J
authors.lastname: Thomas
authors.affiliation: Vanderbilt University Medical Center, Nashville, Tennessee.
authors.forename: Mark C
authors.initials: MC
authors.lastname: Adams
authors.affiliation: Vanderbilt University Medical Center, Nashville, Tennessee.
authors.forename: John W
authors.initials: JW
authors.lastname: Brock
authors.affiliation: Vanderbilt University Medical Center, Nashville, Tennessee.
authors.forename: Charles F
authors.initials: CF
authors.lastname: Caskey
mesh_terms: D000818:Animals; D005260:Female; D009119:Muscle Contraction / Q000502:physiology*; D009130:Muscle, Smooth / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012018:Reflex / Q000502:physiology*; D013979:Tibial Nerve / Q000502:physiology; D014463:Ultrasonography; D014554:Urination / Q000502:physiology*
keywords: focused ultrasound; neuromodulation; posterior tibial nerve stimulation