The activity of acetylcholinesterase (AChE), 5'-nucleotidase (NT) and adenylate cyclase (AC) were studied in sensomotor cortex and neostriatum (NS) from right and left hemispheres of control and experimental rats, trained to perform food reaching with pushing on operant by preferable forepaw. The levels of summarized bilateral activity of NT as well as of AC were found to be similar in both studied structures of control rats, while the activity of AChE was higher in NS than in cortex. In trained rats the activity of AC was decreased both in cortex and NS, the activity of NT was decreased in cortex and increased in NS, AChE being not changed when compared with control. The bilateral values of enzyme activities in well and badly learning rats were significantly different. Meanwhile, when the dominant and subdominant hemispheres were compared these values were found to be similar. In general, the results obtained could be evaluated as specific features of conditioned unilateral manipulatory reactions, characteristic for cortex and NS of brain hemispheres.