Progesterone modulation of diazepam withdrawal syndrome in mice

The influence of progesterone and oestrogens on the benzodiazepine withdrawal syndrome in mice was studied. The intraperitoneal administration of 15 mg/kg of flumazenil induced a withdrawal syndrome in chronic diazepam-treated mice, characterized by jerks, usually accompanied by tail lifts, and seizures. The principal finding of the present work is that the intensity of diazepam withdrawal syndrome was significantly reduced by acute administration of progesterone as revealed by a low incidence of jerks and seizures. The action of progesterone could be due to a modulatory role of the hormone on neuronal activity as an anxiolytic agent. The modulatory activity of progesterone appears to be related to changes in the pharmacological properties of benzodiazepine receptors.