OBJECTIVETo explore and compare the effects of propofol, ginsenoside Rg-1, protein phosphatae-2A, and lithium on the learning and memory and the concentration of glutamic acid in hippocampus after the electroconvulsive therapy (ECT) in the model of depressed rats induced after the removal of olfactory bulb.

METHODSThe depressed rats were randomized into ECT intervention (two levels:no disposition and a course of electroconvulsive shock) and drug intervention (five levels:microinjection of saline injection, propofol, ginsenoside Rg-1, protein phosphatae-2A, and lithium, 20 g/L). Learning and memory were evaluated using the Morris water maze test within 24 h after the course of ECT. Glutamate contents in the hippocampus of rats were examined using high-performance liquid chromatography.

RESULTSBoth propofol alone and ECT alone induced the impairment of learning and memory in depressed rats, but their combination alleviated the such impairment caused by ECT. Ginsenoside Rg-1, protein phosphatae-2A ,and lithium had no obvious effect on the leaning and improved the learning and memory when in combination with ECT. There was a synergic effect between ECT intervention and drug intervention. ECT remarkably increased the glutamate content in the hippocampus of depressed rats, which could be reduced by both propofol and ginsenoside Rg-1. Protein phosphatae-2A and lithium did not affect glutamate content in the hippocampus of depressed rats before and after ECT.

CONCLUSIONSECT can increase the content of glutamate in hippocampus and thus cause the impairment of learning and memory in depressed rats. Propofol and ginsenoside Rg-1 can ameliorate the impairment by reducing the content of glutamate in hippocampus. Protein phosphatae-2A and lithium may also improve the learning and memory in depressed rats.