Abstract.
The hyperpolarization of the electrical plasma membrane potential difference has been identified as an early response of plant cells to various signals including fungal elicitors. The hyperpolarization-activated influx of Ca2+ into tomato cells was examined by the application of conventional patch clamp techniques. In both whole cell and single-channel recordings, clamped membrane voltages more negative than −120 mV resulted in time- and voltage-dependent current activation. Single-channel currents saturated with increasing activities of Ca2+ and Ba2+ from 3 to 26 mm and the single channel conductance increased from 4 pS to 11 pS in the presence of 20 mm Ca2+ or Ba2+, respectively. These channels were 20–25 and 10–13 times more permeable to Ca2+ than to K+ and to Cl−, respectively. Channel currents were strongly inhibited by 10 μm lanthanum and 50% inhibited by 100 μm nifedipine. This evidence suggests that hyperpolarization-activated Ca2+-permeable channels provide a mechanism for the influx of Ca2+ into tomato cells.
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Received: 13 February 1996/Revised: 12 August 1996
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Gelli, A., Blumwald, E. Hyperpolarization-activated Ca2+-permeable Channels in the Plasma Membrane of Tomato Cells . J. Membrane Biol. 155 , 35 –45 (1997). https://doi.org/10.1007/s002329900156
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DOI: https://doi.org/10.1007/s002329900156