title: Effect of a 5-HT(1A) receptor agonist (8-OH-DPAT) on the external urethral sphincter activity in the rat.
abstract: OBJECTIVE
  This study examined the effects of a 5-HT(1A) receptor agonist (8-OH-DPAT) on external urethral sphincter (EUS) activity in urethane-anesthetized rats.
  
  
  METHODS
  An EUS electromyogram (EMG) and intravesical pressure (IVP) were simultaneously recorded during continuous cystometrographic monitoring, to provide a quantitative evaluation of EUS activity and urethral urodynamics of voiding.
  
  
  RESULTS
  When examining the EUS burst activity, durations of the active (AP) and silent periods (SP) as a function of the time axis, respectively, exhibited concave- and convex-shaped curves. The burst discharges of the EUS-EMG were divided into nonvoiding and voiding burst activities based on the oscillation waves of the IVP, which were located in Phases 1 and 2 of the IVP. After 8-OH-DPAT treatment, the entire burst period in Phases 1 to 2 of the IVP was significantly prolonged. The average SP in both Phases 1 and 2 significantly increased but the average APs were not affected. Urodynamic results showed decreases in the volume threshold, contraction amplitude, and residual volume as well as an increase in the contraction duration. In addition, the amplitude of bladder high-frequency oscillatory waves in the IVP and the average urethral flow rate were reduced, but the entire voiding efficiency increased.
  
  
  CONCLUSIONS
  The influences of 8-OH-DPAT on EUS burst activity and urodynamics were exactly detected by the sophisticated EMG analytic design, and the results could be a reference for the pharmacological treatment of patients with lower urinary tract dysfunction.
authors.affiliation: Department of Physical Medicine and Rehabilitation, School of Medicine, College of Medicine, Taipei Medical University, Taipei 110, Taiwan, ROC.
authors.forename: Shih-Ching
authors.initials: SC
authors.lastname: Chen
authors.forename: Wen-Jia
authors.initials: WJ
authors.lastname: Fan
authors.forename: Chien-Hung
authors.initials: CH
authors.lastname: Lai
authors.forename: Jia-Jin
authors.initials: JJ
authors.lastname: Jason Chen
authors.forename: Chih-Wei
authors.initials: CW
authors.lastname: Peng
mesh_terms: D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000008:administration & dosage / Q000494:pharmacology*; D018686:Anesthetics, Intravenous / Q000008:administration & dosage; D000818:Animals; D004576:Electromyography; D005260:Female; D011312:Pressure; D051381:Rats; D017207:Rats, Sprague-Dawley; D017366:Serotonin Receptor Agonists / Q000008:administration & dosage / Q000494:pharmacology*; D014520:Urethane / Q000008:administration & dosage; D014521:Urethra / Q000187:drug effects* / Q000502:physiology; D001743:Urinary Bladder / Q000187:drug effects* / Q000502:physiology; D014554:Urination / Q000187:drug effects* / Q000502:physiology
chemical_list: D018686:Anesthetics, Intravenous; D017366:Serotonin Receptor Agonists; D014520:Urethane; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin