title: Characterizing behavior of corpus cavernosum in chloride-free condition.
abstract: OBJECTIVE
  To elucidate the role of chloride currents in erectile function through characterizing the behavior of corpus cavernosum (CC) in chloride-free (Cf) medium, which has not been evaluated before.
  
  
  METHODS
  Isolated rabbit CC strips were suspended in thermo-regulated organ baths containing oxygenated Tyrode for isometric tension recording. Cf Tyrode was prepared by substituting sodium chloride, calcium chloride, and potassium chloride (KCl) with equivalent molar concentrations of sodium acetate, calcium acetate, and potassium acetate salts. Resting cavernosal tone and contractions by noradrenaline, histamine, and KCl were assessed in Cf Tyrode with or without chloride channel blockers, niflumic acid (NFA), and anthracene-9-carboxylic acid (A9C).
  
  
  RESULTS
  Withdrawal of extracellular chloride caused myogenic contractions in the unstimulated CC strips (n = 18). In addition, peak contractions by noradrenaline (n = 14) and histamine (n = 13) were augmented in Cf buffer by 47.2 ± 5.9% and 85.4 ± 13.2%, respectively (P <.05), whereas KCl contractions were not significantly altered (17.6 ± 4.6%; n = 7). Interestingly, Cf buffer exerted opposing effects, potentiation and reduction, respectively, on the plateau phase of contractions mediated by noradrenaline and histamine. The stimulatory effect of Cf buffer on the intrinsic myogenic tone was diminished by NFA (30 μM), and A9C (300 μM-1 mM). NFA (30-100 μM), however, specifically reduced the plateau phase without significantly modifying the peak contraction of noradrenaline in Cf buffer.
  
  
  CONCLUSIONS
  These results reiterate the importance of chloride currents as a mechanism underlying the maintenance of penile cavernosal tone. Thus, chloride channel could be an effective alternative target to regulate penile erection.
authors.affiliation: Department of Obstetrics & Gynaecology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
authors.forename: Lang-Chu
authors.initials: LC
authors.lastname: Lau
authors.forename: P Ganesan
authors.initials: PG
authors.lastname: Adaikan
authors.forename: Arunmozhiarasi
authors.initials: A
authors.lastname: Armugam
authors.forename: Kandiah
authors.initials: K
authors.lastname: Jeyaseelan
mesh_terms: D000818:Animals; D002712:Chlorides; D066298:In Vitro Techniques; D007552:Isotonic Solutions; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D009129:Muscle Tonus / Q000502:physiology; D009130:Muscle, Smooth / Q000502:physiology*; D010413:Penis / Q000502:physiology*; D011817:Rabbits
chemical_list: D002712:Chlorides; D007552:Isotonic Solutions; C037692:Tyrode's solution