[Participation of brain-specific S-100-group proteins in the neurophysiological mechanisms of habituation].

The possible role of S-100 brain specific proteins and their participation in the neuronal mechanisms of habituation were studied on identified neurons of the snail Helix pomatia. Extracellular application and intracellular injection of antibodies to S-100 proteins caused a rapid and significant decrease of neuronal responses to repeated stimulation in comparison with the control. During the action of antibodies a significant decrease of the evoked EPSP amplitude, increase of the action prepotential latency and a decrease in discharge frequency were observed. At the same time the membrane potential, membrane input impedance, pacemaker potentials did not change. The obtained effect is supposed to be caused by interruption of the synaptic transmission. Possible involvement of S-100 protein in the functioning of synaptic structures as one of the integrating apparatus of the neuron is discussed.