Biphasic voltage relaxation pattern observed in cells of Eremosphaera viridis after injection of charge-pulses of short duration: detection of tip clogging of intracellular microelectrodes by charge-pulse technique

摘要: Abstract Charge pulse experiments performed on the peat-bog alga Eremosphaera viridis revealed an unusual voltage relaxation behaviour. Injection of charge pulses 1 μs duration resulted in immediate charging membranes (time constant order 40 ns). Nevertheless, potential-measuring microelectrode recorded exponential increase membrane with a time about 1.3 ms. The maximum value was after 3 ms, followed by decay 9.6 This biphasic course independent amplitude injected and location impaled microelectrodes vacuole. Centrifuged cells which chloroplasts other organelles were pelleted one part showed same electrical response. Electrical breakdown cell disappearance In this case only decaying process could be After resealing original response restored. Increasing concentrations KCl bathing medium reduced both constants almost correspondingly. experimental findings evaluated equivalent circuit. Theoretical analysis reference to data suggested that delayed potential-recording electrode from seal across tip electrode. resistance calculated 400 MΩ. specific resistances capacitances tonoplast plasmalemma curves. average values found 2.58 Ω· m 2 5 mF · −2 . investigations reported here suggest can generally used for detection cytoplasmic material clogging intracellular microelectrodes, problem most electrophysiologists are faced when interpreting obtained microelectrodes.