Relaxant effect of diallyl sulfide on nonpregnant rat uterus: Involvement of voltage-dependent calcium channels

Abstract

Aim We aimed to determine the effect and mechanism of action of diallyl sulfide (DAS), an active component of sulfur-containing foods such as garlic on rat uterine activity. Methods Isometric tension changes in longitudinal uterine strips obtained from 20 female Sprague-Dawley rats (250-300 g) in estrus stage of estrous cycle were studied in isolated organ baths containing Krebs-Henseleit solution. Results Diallyl sulfide (10(-8)-10(-6) M) caused a concentration-dependent relaxation on KCl (60 mM)-induced contractions and inhibited spontaneous peristaltic activity of uterine strips (P < 0.05). None of the following antagonists significantly changed the inhibitory effect of DAS on both KCl-precontracted uterine strips and spontaneous peristaltic activity of the uterus (P > 0.05): nitric oxide synthase inhibitor L-NAME (10(-4) M), hydrogen sulfide-producing enzymes cystation beta synthase and cystation gamma-lyase inhibitors, aminooxyacetic acid (10(-4) M) and propargylglycine (10(-3) M) and nonselective cyclooxygenase inhibitor indomethacin (10(-4) M). However, in calcium-free Krebs solution containing high KCl (30 mM), DAS significantly inhibited CaCl2(10(-5)-10(-2) M)-induced uterine contractions in a concentration-dependent manner (P < 0.05). Conclusion Diallyl sulfide has a relaxing effect on KCl-contracted rat uterus strips and an inhibitory effect on spontaneous uterine activity, possibly by decreasing the calcium influx into the cytoplasm of uterine smooth muscle cells.