Memory storage and effect of repeated treatment with a new antidepressant drug: rubidium chloride.

Following 15 days' treatment with saline, 48 mg/kg rubidium chloride, 5 mg/kg imipramine hydrochloride, 10 mg/kg sodium phenobarbitone, 1000 mg/kg piracetam, or 0.20 mg/kg strychnine nitrate all administered intraperitoneally, mice were evaluated by habituation of exploratory activity using an open-field apparatus. In control animals a significant (P less than 0.05) decrease in open-field responses (ambulation, rearing and defaecation) was seen following a 1-day intersession interval and there was no retention of exploratory activity after a 5-day intersession interval. Administration of imipramine or phenobarbitone for 15 days was found to impair retention of memory after 1 day, whereas treatment with rubidium chloride, piracetam, or strychnine for 15 days improve retention after a 5-day intersession interval.