Investigation of neuronal transport in the cerebral cortex of the cat

[ 3 H]Glycine was applied to the acoustic cortex of anaesthetized cats during continuous click stimulation for 1 and 9 h, respectively. In other experiments (4 h) stimulation periods of 5 min alternated with 20 min rest. The underlying cortical areas were excised and processed for light and electron microscopic autoradiography. After 1 h of [ 3 H]glycine application labelled proteins appeared in the perikaryon and proximal segments of dendrites. In the case of 4 h application more distant dendritic regions and axon terminals also became labelled. After 9 h glycine application the number of pre- and postsynaptically labelled terminals showed a considerable increase. During periodic stimulation dendritic labelling became intermittent. Distances between groups of silver grains allowed assessment of dendritic transport rate.