title: Effects of the antidepressant St. John's wort (Hypericum perforatum) on rat and human vas deferens contractility.
abstract: OBJECTIVE
  Since sexual dysfunction related to vas deferens smooth muscle contractility is a possible side effect of St. John's wort (SJW) (Hypericum perforatum) we evaluated the effect of this herbal antidepressant on rat and human vas deferens contractility.
  
  
  METHODS
  The effect of SJW was evaluated on contractions induced by electrical field stimulation or exogenous agonists (alpha,beta-methylene adenosine triphosphate and phenylephrine) in isolated rat and human vas deferens.
  
  
  RESULTS
  SJW (1 to 300 microM) decreased in a concentration dependent manner the amplitude of electrical field stimulation and agonist induced contractions with the same potency, suggesting direct inhibition of rat vas deferens smooth muscle. Of the chemical constituents of SJW tested hyperforin but not hypericin or the flavonoids quercitrin, rutin and kaempferol inhibited phenylephrine induced contractions. SJW and hyperforin also inhibited phenylephrine induced contractions in human vas deferens
  
  
  CONCLUSIONS
  The results of our study demonstrate that SJW directly inhibits rat and human vas deferens contractility. If confirmed in vivo, these results suggest that SJW might affect sexual function in humans. These results might explain delayed ejaculation described in patients receiving SJW.
authors.affiliation: Departments of Experimental Pharmacology and Urology, University of Naples Federico II, Naples Italy.
authors.forename: Raffaele
authors.initials: R
authors.lastname: Capasso
authors.forename: Francesca
authors.initials: F
authors.lastname: Borrelli
authors.forename: Vittorino
authors.initials: V
authors.lastname: Montanaro
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Altieri
authors.forename: Francesco
authors.initials: F
authors.lastname: Capasso
authors.forename: Angelo A
authors.initials: AA
authors.lastname: Izzo
mesh_terms: D000818:Animals; D000873:Anthracenes; D000928:Antidepressive Agents / Q000494:pharmacology*; D001643:Bridged Bicyclo Compounds / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004542:Ejaculation / Q000187:drug effects; D006801:Humans; D020902:Hypericum; D007537:Isometric Contraction / Q000187:drug effects*; D008297:Male; D009130:Muscle, Smooth / Q000187:drug effects*; D009948:Orgasm / Q000187:drug effects; D010569:Perylene / Q000031:analogs & derivatives* / Q000494:pharmacology*; D010696:Phloroglucinol / Q000031:analogs & derivatives* / Q000494:pharmacology*; D051381:Rats; D013729:Terpenes / Q000494:pharmacology*; D046509:Tissue Culture Techniques; D014649:Vas Deferens / Q000187:drug effects*
chemical_list: D000873:Anthracenes; D000928:Antidepressive Agents; D001643:Bridged Bicyclo Compounds; D013729:Terpenes; D010569:Perylene; C004965:hypericin; D010696:Phloroglucinol; C001654:hyperforin