Transistor probes local potassium conductances in the adhesion region of cultured rat hippocampal neurons

Adhesion interactions of neurons in a tissue may affect the ion conductance of the plasma membrane, inducing selective localization and modulation of channels. We studied the adhesion region of cultured neurons from rat hippo campus as a defined model where such effects could be observed electrophysi ologically, taking advantage of extracellular recording by a transistor int egrated in the substrate. We observed the K+ current through the region of soma adhesion under voltage-clamp and compared it with the current through the whole cell. We found that the specific A-type conductance was depleted, even completely, in the region of adhesion, whereas the specific K-type co nductance was enhanced up to a factor of 12. The electrophysiological appro ach opens a new way to investigate targeting of ion channels in the cell me mbrane as a function of adhesion processes.