＜Poster＞Modulation of neuronal activities by interactions between neurons and glial cells

Action potentials are the fundamental signals for relaying information from one region to another in the nervous system. Action potentials are propagated along axons without decrease of their amplitudes and are conducted with constant velocity depending on axonal diameter and myelin. It is considered that the modulation of firing patterns of action potentials in the neural circuit infl uences the information processing in the brain. We investigated the modulatory eff ects of glial cells on the fi ring pattern and the axonal conduction of action potentials using rat hippocampal slice preparation. In our previous study, we focused on interneuron / perineuronal glial cell pairs in CA1 region and reported that perineuronal glial cells could be classifi ed into two groups, one group belong astrocytes （perineuronal astrocytes） and the other group oligodendrocytes （perineuronal oligodendrocytes）, based on their membrane properties and immunohistochemical study. Direct depolarization of perineuronal astrocytes modulated the directly induced fi ring pattern of the interneuron, with initial facilitation and subsequent suppression. We also studied the oligodendrocytes in the alveus and examined their modulatory effects on the conduction of action potentials along axons of CA1 pyramidal cells. Direct repetitive depolarization of oligodendrocytes shortened the latencies of action potentials evoked by antidromic stimulation. These results indicate that glial cells infl uence the firing pattern and axonal conduction of action potentials, and that their effects involve both facilitation and suppression.
弘前医学. 61(Suppl.), 2010, p.S174-S180