title: Acute effects of serotonin on rat bladder contractility.
abstract: BACKGROUND
  The purpose of this study is to investigate in vitro the effects of serotonin on the rat detrusor. In particular, it examines which drugs inhibit the serotonin-induced detrusor contractions.
  
  
  METHODS
  Isometric tension changes of isolated rat bladder muscle strips were recorded in an organ bath using a force transducer. Acute effects of serotonin (0.0001-0.01 mM) on resting tension were assessed. Electrical field stimulation (EFS); bethanechol (0.0001-0.01 mM); ATP (1-3 mM)- or KCl (63.5-254 mM)-induced contractions using an application in an organ bath were compared with serotonin-induced contractions. In order to examine the action mechanism of serotonin-induced stimulation, EFS-, bethanechol-, ATP- or KCl-induced contraction on serotonin treatment (0.001 mM) was assessed and serotonin (0.001-0.1 mM) was cumulatively added to the organ bath following preincubation with propranolol, ketanserin, tropisetron, propiverine, sodium nitroprusside or doxazosin.
  
  
  RESULTS
  The serotonin-induced response has two phases: an initial transient contraction and a prolonged tonic phase. Serotonin produced a reversible and dose-dependent contraction of the detrusor strips. Responses to bethanechol significantly increased with a concentration of 0.001 mM serotonin (p < 0.05). There was no effect on the responses to ATP, KCl, or EFS on 0.001 mM serotonin. The 5-HT(2) receptor is mainly responsible for serotonin-induced contractions of the detrusor (p < 0.05), while the 5-HT(1) receptor is partially responsible. Doxazosin and propiverine each significantly suppressed the response to serotonin, while sodium nitroprusside and tropisetron each had no effect (p < 0.05).
  
  
  CONCLUSIONS
  Because the 5-HT(2) antagonist blocked the effect of serotonin-induced bladder contractions and the stimulation of the adrenoreceptors, the 5-HT(2) antagonist seems to improve lower urinary tract symptoms.
authors.affiliation: Department of Urology, Dankook University College of Medicine, Cheonan, Chungnam, Korea. shimwon2@anseo.dankook.ac.kr
authors.forename: Hyung Jee
authors.initials: HJ
authors.lastname: Kim
authors.forename: Gilho
authors.initials: G
authors.lastname: Lee
authors.forename: Dong Hee
authors.initials: DH
authors.lastname: Kim
authors.forename: Suk Jae
authors.initials: SJ
authors.lastname: Lee
authors.forename: Duck Ki
authors.initials: DK
authors.lastname: Yoon
authors.forename: Jae Heung
authors.initials: JH
authors.lastname: Cho
mesh_terms: D000818:Animals; D018723:Bethanechol / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D008297:Male; D023421:Models, Animal; D009119:Muscle Contraction / Q000187:drug effects* / Q000502:physiology; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology; D011336:Probability; D051381:Rats; D017207:Rats, Sprague-Dawley; D012016:Reference Values; D012680:Sensitivity and Specificity; D012701:Serotonin / Q000494:pharmacology*; D001743:Urinary Bladder / Q000187:drug effects*
chemical_list: D018723:Bethanechol; D012701:Serotonin