The aim of this study was to investigate the effects of alpha-adrenerg
ic antagonists on the motor activity of the postpartum uterus of the r
at in vivo. Intrauterine pressure was assessed by means of a Millar ca
theter fitted with a latex microballoon. Some of the tested compounds
(urapidil, yohimbine, phentolamine, benoxathian and prazosin) decrease
d the uterine activity to a significant extent (57.4-67.4%). However,
none of the investigated alpha-receptor blockers exerted the same effe
ct as beta-adrenergic agonists. Our results suggest that alpha-adrener
gic antagonists could possibly be used as an alternative to beta-adren
ergic agonists in clinical tocolysis after an appropriate clinical eva
luation. (C) 1997 Elsevier Science Inc.