The effect of acute, 7-fold and 14-fold noopept (1 mg/kg/day) administration on the dynamics of anxiolitic and nootropic behavioral effects in cross-maze, as well as their correlations with NMDA- and BDZ-receptor density was studied in inbred mice strains, differing in exploratory and emotional status--C57BL/6 and BALB/c. The dipeptide failed to affect the anxiety and exploration activity in C57BL/6 mice at each of 3 steps of experimental session. In this strain the B(max) values of [3H]-MK-801 and [3H]-Flunitrazepam binding changed only after single administration. In respect to BALB/c mice noopept induced both the anxiolitic and nootropic effects reaching their maximum on 7th day. In BALB/c strain the dynamics of hippocampal NMDA-receptor binding corresponds to the dynamics of exploratory efficacy whereas the dynamics of BDZ-receptors in prefrontal cortex was reciprocally to dynamics of anxiety level.
