Abstract 1. 1. In the case of an intraperitoneal propranolol injection to rats (25 mg/kg), there was no modification in benzodiazepine and γ-amino-butyric acid recognition sites since [ 3H]diazepam or [ 3H]-muscimol binding was not affected. 2. 2. There was an increase in GABA stimulated-diazepam binding (100%, statistical risk lower than 1%). 3. 3. This last result suggests that propranolol treatment can stimulate GABA-benzodiazepine receptor coupling.