title: Influence of urethane-anesthesia on the effect of resiniferatoxin treatment on bladder function in rats with spinal cord injury.
abstract: OBJECTIVE
  We investigated the effect of resiniferatoxin (RTX)-treatment on cystometric parameters in the spinal cord injury (SCI) rats in both conscious and urethane-anesthetized conditions and evaluated the influence of urethane-anesthesia on the effect of RTX on lower urinary tract (LUT) function in SCI rats.
  
  
  METHODS
  Female Sprague-Dawley rats were used. SCI was created by transection of the T8-T9 spinal cord. Four weeks after the transection, the animals were placed in a restraint cage for the first cystometric measurements in a conscious state. Secondary cystometric measurements were performed in a conscious condition following the 1 day after RTX-(0.3 mg/kg) or vehicle-subcutaneous injection. Then the animals were injected with urethane (1.5 g/kg, subcutaneously), and cystometric measurements were repeated four times every 1 hr-interval.
  
  
  RESULTS
  After the RTX-treatment in a conscious condition, urinary retention was observed in three out of five animals. In addition, the number of non-voiding contractions (NVCs) significantly decreased although their amplitude did not change significantly. After the urethane-injection, all of the animals treated with RTX developed urinary retention. The amplitude of NVCs significantly decreased, whereas the number of NVCs did not change significantly in the RTX-treated group. No cystometric parameters significantly changed after either vehicle- or urethane-injection in the vehicle-treated group.
  
  
  CONCLUSIONS
  The present results indicate that the suppressive effects of RTX on NVCs as well as voiding contractions in SCI rats can be enhanced by urethane-anesthesia. Such suppressive effect of urethane-anesthesia itself should be taken into consideration when we evaluate a drug-effect on LUT function in rats with SCI.
authors.affiliation: Department of Continence Medicine, The University of Tokyo Graduate School of Medicine, Tokyo, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Aizawa
authors.forename: Shinichi
authors.initials: S
authors.lastname: Ogawa
authors.forename: Rino
authors.initials: R
authors.lastname: Sugiyama
authors.forename: Yukio
authors.initials: Y
authors.lastname: Homma
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Igawa
mesh_terms: D000758:Anesthesia; D018686:Anesthetics, Intravenous / Q000494:pharmacology*; D000818:Animals; D004224:Diterpenes / Q000494:pharmacology*; D004347:Drug Interactions; D005260:Female; D051381:Rats; D017207:Rats, Sprague-Dawley; D013119:Spinal Cord Injuries / Q000503:physiopathology*; D014520:Urethane / Q000494:pharmacology*; D001743:Urinary Bladder / Q000187:drug effects* / Q000503:physiopathology*
chemical_list: D018686:Anesthetics, Intravenous; D004224:Diterpenes; D014520:Urethane; C024353:resiniferatoxin
keywords: Sprague-Dawley rats; anesthesia; resiniferatoxin; spinal cord injury; urinary bladder