[Action of the fluorocarbons, 12 (difluorodichloromethane) and 11 (monofluorotrichloromethane), on smooth muscle].

We have studied the action of difluorodichloromethane (F12) and monofluorotrichloromethane (F11) on the rat isolated uterine muscle and the rabbit isolated duodenum. Both gases in the nutritive solution after the functioning of these organs in a way which is, moreover, non identical. On the uterus both gases show an inhibitory effect against the spontaneous contractions. On the duodenum, both gases inhibit the phasic contractions but the basal tonus is strongly increased by F12, and on the contrary reduced by F11. The action is a musculotrop one and quite reversible in every case. Both gases do not modify the action of acetylcholin, epinephrin and histamin.