The electromotor system of Torpedo marmorata was used to investigate effects of evoked neuronal activity on protein synthesis in neuronal perikarya. At different times after electrical or mechanical stimulation, fish were killed and the RNA of the electric lobes isolated and used to prime a cell-free translation system. The radioactively labeled synthesis products were separated by 2-D electrophoresis and the patterns obtained from different specific RNAs were compared. Several proteins exhibited time-dependent changes in rate of synthesis as indicated by the relative intensity of their autoradiographic spots. These proteins appear/disappear in a specific way, indicating a modulated translational response to neuronal activity.