title: Dual effects of melatonin on uterine myoelectrical activity of non-pregnant rats.
abstract: OBJECTIVE
  In this experimental study, we aimed to investigate the role of melatonin on uterine myoelectrical activity of non-pregnant rats.
  
  
  METHODS
  Forty-six female rats were assigned to six groups: (1) control; (0.2 mL 0.9% NaCl was injected intravenously (IV), n=6); (2) melatonin applied as 0.4 mg/kg/IV (n=8); (3) melatonin applied as 4 mg/kg/IV (n=8); (4) single dose of oxytocin (100 mU/kg) injected IV (n=8); (5) melatonin (0.4 mg/kg) plus oxytocin (100 mU/kg) (n=8); and (6) melatonin (4 mg/kg) plus oxytocin (100 mU/kg) injected IV (n=8). Each rat underwent a laparotomy, and uterine myoelectrical signals were recorded. The mean spectrum, averaged over the spectral content of signals in each group, was compared.
  
  
  RESULTS
  Melatonin induced uterine myoelectrical activity in a dose-dependent manner. Treatment of melatonin after oxytocin suppressed the mean power of the signals. Serum melatonin concentrations were significantly higher in melatonin-treated rats.
  
  
  CONCLUSIONS
  Melatonin itself at two different dose levels was found to be equally effective in stimulating the uterine electrical signals, although oxytocin-induced uterine electrical activity was suppressed by melatonin. These findings merit further investigations on the possible beneficial role of melatonin in the treatment of conditions associated with abnormal uterine activity.
authors: Department of Obstetrics and Gynecology, Kırıkkale University Faculty of Medicine, Kırıkkale, Turkey.
authors: Yavuz
authors: Y
authors: Simşek
authors: Department of Medical Pharmacology, İnönü University Faculty of Medicine, Malatya, Turkey.
authors: Hakan
authors: H
authors: Parlakpınar
authors: Department of Obstetrics and Gynecology, İnönü University Faculty of Medicine, Malatya, Turkey.
authors: Uğur
authors: U
authors: Turhan
authors: Department of Electrical and Electronics, İnönü University Faculty of Engineering, Malatya, Turkey.
authors: Mehmet Emin
authors: ME
authors: Tağluk
authors: Department of Chemistry, İnönü University Faculty of Science, Malatya, Turkey.
authors: Burhan
authors: B
authors: Ateş
keywords: Uterine contraction; electrical stimulation; melatonin; oxytocin