Effects of thiopentone and chlormethiazole on human myometrial arteries from term pregnant women

Abstract

We have investigated the effects of thiopentone and chlormethiazole on maternal intramyometrial arteries dissected from myometrial biopsies taken during Caesarean section at term. Ring preparations were mounted in organ baths and isometric tension was recorded. Thiopentone 10-4-10-3 mol litre-1 inhibited responses to K+ depolarization, nor-adrenaline and vasopressin. Chlormethiazole 3×10-5-3×10-3 mol litre-1 inhibited responses to noradrenaline, while a concentration of 3×10-3 mol litre-1 was required to attenuate responses to vasopressin and K+ depolarization. Neither of the two agents affected relaxant responses to prosta-cyclin. The results did not yield evidence that clinical use of thiopentone and chlormethiazole should impair uteroplacental vascular perfusion by a direct effect. © 1992 British Journal of Anaesthesia.