Role of benzodiazepine receptor in amnesic effect of different intravenons anesthetics in mice

Abstract

Objective To investigate the role of the benzodiazepine receptor in the amnesic effect of propofol, etomidate and ketamine in mice. Methods Two hundred and eighty-eight Kunming mice of both sexes weighing 18-23 g were randomly divided into 9 groups（ n = 32 each） ： group normal saline ＋ normal saline （group NN） ; group normal saline ＋ fat emulsion （group NF） ; group flumazenil ＋ normal saline （group FN） ; group nor- mal saline ＋ propofol （group NP） ; group flumazenil ＋ propofol （group FP） ;group normal saline ＋ etomidate （group NE）; group flumazenil ＋ etcimidate （group FE ）; group normal saline ＋ ketamine （group NK ） and group flumazenil ＋ ketamine （group NK）. Normal saline 10 ml/kg was given IP at 10 min before the tests, and normal saline 10 ml/kg, fat emulsion 10 ml/kg, propofol 25 mg/kg, etomidate 3 mg/kg and ketamine 20 mg/kg at 5 min before the tests in groups NN, NF, NP, NE and NK respectively. Flumazenil 1 mg/kg was given IP at 10 rain before the tests, and normal saline 10 ml/kg, fat emulsion 10 ml/kg, propofol 25 mg/kg, etomidate 3 mg/kg and ketamine 20 mg/kg at 5 min before the tests in groups NN, NF, NP, NE and NK respectively. Darkness-avoiding test, platform-mounting test and Morris water maze test were performed to assess the cognition function. The latency of response and number of error were recorded in each test. Results Propofol, etomidate and ketamine signifi-canfly shortened the duration of latency of response in platform-mounting test as compared with group NN. Etomidate also significantly increased the number of error in platform-mounting test as compared with group NN, while ketamine prolonged the duration of latency of response in Morris water maze test as compared with group NN. Flumazcnil significantly counteracted the above action of the 3 intravenous anesthetics. Conclusion Benzodiazepine receptor may play an important role in the amnesic effect induced by propofol, etomidate and ketamine. Key words: Receptors, GABA-A ; Amnesia; Propofol ; Etomidate ; Ketamine