The contribution of nitric oxide and endothelins to angiotensin II. Evoked responses in the rat isolated uterus smooth muscle

• Published in: General pharmacology 1999-10, Vol.33 (4), p.307-312
• Main Authors: Keskil, Zuhal, Bayram, Merih, Ercan, Z.Sevim, Türker, R.Kazim
• Format: Article
• Language: English
• Subjects: Angiotensin II (AII); Angiotensin II - pharmacology; Animals; Azepines - pharmacology; Biological and medical sciences; Dose-Response Relationship, Drug; Endothelin Receptor Antagonists; Endothelins; Endothelins - physiology; Enzyme Inhibitors - pharmacology; Female; Fundamental and applied biological sciences. Psychology; Hormone metabolism and regulation; In Vitro Techniques; Mammalian female genital system; Muscle Contraction - drug effects; Muscle, Smooth - drug effects; Muscle, Smooth - physiology; NG-Nitroarginine Methyl Ester - pharmacology; Nitric oxide (NO); Nitric Oxide - physiology; Nitric Oxide Synthase - antagonists & inhibitors; Oligopeptides - pharmacology; Rats; Rats, Wistar; Receptor, Endothelin A; Uterus (Rat); Uterus - drug effects; Uterus - physiology; Vertebrates: reproduction
• ISSN: 0306-3623; 1879-0011
• DOI: 10.1016/S0306-3623(99)00024-5

The present study was designed to determine the role of endogenous endothelin peptides and nitric oxide on angiotensin II (AII) responses in the isolated nonpregnant rat uterine smooth muscle. AII (10, 20, or 50 ng/ml) increases rhythmic oscillations dose dependently (32.7 ± 8.9, 55.96 ± 10.3, and 62.78 ± 17.7% increase, respectively). L-arginine methyl ester (L-NAME; 10 −5 M) did not affect the increase in rhythmic oscillations induced by AII (10, 20, or 50 ng/ml) (17.5 ± 12.1, 31.5 ± 18.3, and 52.5 ± 11.8% increase, respectively, n = 6, p > 0.05). It reduced the contractile responses to AII (10 ng/ml: from 4.63 ± 0.6 to 1.8 ± 0.7 cm 2, p < 0.05; and 20 ng/ml: from 5.59 ± 0.8 to 2.11 ± 0.4 cm 2, p < 0.05, n = 6). L-arginine (10 mM) decreased the contractile response obtained by AII (10 or 20 ng/ml) (1.93 ± 1.05, p < 0.05 and 2.14 ± 0.7 cm 2, p < 0.05, respectively, n = 6). BQ 485 (50 ng/ml) decreased both the number of rhythmic oscillations and the contractility increased by AII. Bosentan (10 −5 M) induced an increase in the number of rhythmic oscillations but decreased the contractile responses to the higher concentrations of AII. These data show that endogenous NO and endothelin peptides contribute to the motility changes induced by AII and may play an important role in the pathophysiological events of the uterine function.