Bevelled Dual-Channel Microelectrodes

Preparation of bevelled dual-channel glass microelectrodes is described. The bevelled tips overcome some of the problems which complicate intracellular recording. The size of the tip opening is increased, resulting in a lower resistance, which in turn confers greater current-carrying capacity and less noise susceptibility. Bevelling also preserves the sharp point, facilitating tissue penetration and minimizing neuronal trauma. The characteristics of bevelled and unbevelled electrodes filled with 0.5 or 3 M KCI, K Acetate and K
2
SO
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were similar. Bevelled electrodes were shown to maintain a near constant resistance during current passage, while unbevelled ones showed changes in resistance that were dependent on current magnitude, polarity and duration. Such changes were caused principally by electro-osmosis.