A reversible decrease in electrical coupling of cultured mouse glial cells induced by superfusion from a micropipette.

Cultured mouse oligodendrocytes were superfused by pressure application to the rear-end of a 3-20 microns micropipette filled with normal bathing fluid. Input resistance was determined during superfusion with two separate electrodes. The input resistance increased reversibly by 90% in 26 cells tested and was unaffected in 39 cells. When pairs of oligodendrocytes were electrically coupled, coupling decreased in a reversible manner during superfusion. Therefore, the flow from a micropipette can uncouple cells, and studies involving application of substances by pressure ejection from microelectrodes must be evaluated with care.