Effects of thiopentone or chlormethazole on human placental stem villous arteries

Abstract

'mol litre-1 and by ch/ormethiazole 3×10-4-3× 10* mol litre-1. Thiopentone 10-410-3mol litre-1 and chlormethiazole 3× x 10-4/>-3× x 10-3 mol litre-1 decreased the tension in vessels previously treated with PGF2a10- 5 mol litre-1. Chlormethiazole 3× 10-3 mol litre'-1 inhibited, and thiopenone 10-4-10'-3 mol litre abolished contractile responses to 5-hydroxytryptamine. Contractions induced by angiotensin II were inhibited by thiopentone 1O-3 mol litre-1 and chlormethiazole 3× 10- 3 mol litre-1. The concentrations of the two drugs needed to affect contractile activation of isolated human stem villous arteries exceeded the free plasma concentrations reached during anaesthesia induced by the agents during Caesarean section, and the present results do not suggest any major effects of thiopentone or chlormethiazole on fetal placenta/ vascular resistance during the clinical use of these drugs. © 1987 British Journal of Anaesthesia.