ELECTROCONVULSIVE STIMULATIONS, LEARNING, AND PROTEIN-CHANGES IN THE RAT-BRAIN

Two groups of rats were subjected to 17 training sessions on an operan t task demanding the sequential operation of two manipulanda, while tw o other groups were left with no training experience. Within both the trained and passive groups one was exposed to a series of 12 electroco nvulsive stimulations. The series of training and stimulation sessions were concurrent but arranged in such a way that at least 24 h always separated training and stimulation. Upon completion of the behavioural part of the experiment the concentrations of the marker proteins neur al cell adhesion molecule (NCAM), D3, synaptophysin, and S100 were est imated in the prefrontal and occipital parts of the cortex, the hippoc ampus, and in the total forebrain. The electroconvulsively stimulated animals demonstrated severe impairment of learning. The pattern of mar ker protein concentrations indicated that acquisition and/or performan ce of the task and exposure to electroconvulsive stimulation were both accompanied by similar patterns of synaptic changes: an increased con centration of small synaptic vesicles in both the prefrontal cortex an d the total forebrain and an increased synaptic remodulation in the pr efrontal cortex.