GABRIELA RUSU-ZOTA, ANDREI LUCA, GABRIELA DUMITRITA STANCIU, VICTORITA SORODOC, MARIA MAGDALENA LEON-CONSTANTIN, BOGDAN STOICA, CRISTINA GALES, TEODORA ALEXA-STRATULAT THE IMIDAZOLINE RECEPTOR ANTAGONISTS IDAZOXAN AND EFAROXAN IMPROVE THE SPATIAL AND REFERENCE MEMORY IN RATS Experimental studies and clinical trials revealed the complex interconnections between imidazoline system and various other mediators such as epinephrine, norepinephrine; thus, explain their involvement in the pathophysiological mechanisms of different motor, behavioral and cognitive disturbances. In this study, we tested the influence induced by idazoxan and efaroxan on the cognitive performances in rats. Groups of 6 adult male Wistar rats were treated intraperitoneally according to the following protocol: group I (Control): distilled water 0.3 ml/100g; group II (IDZ): 3 mg/kg idazoxan and group III (EFR): 1 mg/kg efaroxan. The effects of the imidazoline receptor antagonists on the rats cognitive functions were assessed using the radial-arm maze, in order to count the time spent into the arms, the number of baited arms visited, but previously explored (working memory errors); the time taken to consume all baits and the number of entering in non-baited arms (reference memory errors). The data were expressed as mean +/- standard deviation, and statistically analyzed using SPSS version 17.0 Software for Windows, followed by ANOVA one-way method. The administration of IDZ, as well as of EFR was accompanied by a substantial diminution in the number of working memory errors, and the period of time to consume all baits, statistically significant (p<0.01) compared to control group. The use of these two imidazoline receptors antagonists resulted in a considerable decrease in the reference memory errors number, statistically significant (p<0.01) compared to the group treated with distilled water. The influence of IDZ on the evaluated parameters was more accentuated than the effects induced by EFR in all sessions of testing, in this behavioral experimental model. Our findings indicate that treatment with both imidazoline receptor antagonists, idazoxan and efaroxan was associated by a facilitation of the short-term memory retention, an enhancement of discriminative spatial learning, and an improvement of long-term memory performance in radial arm maze in rats.
Keywords: imidazoline receptors antagonists, spatial and reference memory, rats