A THIRD TYPE OF INHIBITION IN THE MAUTHNER CELL OF GOLDFISH

Abstract

Analysis of collateral inhibition in the Mauthner cell disclosed that there existed, in addition to the two previously described, a different type of inhibition whose action, as estimated by a reduction of the EPSP size, was not correlated with an increase of the membrane conductance of the cell. Clear evidence for this was obtained with the help of procaine which, when injected into the animal, blocked the post-synaptic inhibition acting on the soma of the Mauthner cell without influencing the new and different type of inhibition. Additional evidence obtained by recording potentials from the afferent fibers, as well as from the dendrite of the Mauthner cell seem to indicate that the inhibitory action concerned is exerted on both the presynaptic elements and the dendrite of this cell.