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.
Original language | English (US) |
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Pages (from-to) | 35-45 |
Number of pages | 11 |
Journal | Journal of Membrane Biology |
Volume | 155 |
Issue number | 1 |
DOIs | |
State | Published - 1997 |
Externally published | Yes |
Keywords
- Calcium channels
- Hyperpolarized electrical membrane potential differences
- Patch clamp
- Signal transduction
- Tomato protoplasts
ASJC Scopus subject areas
- Biophysics
- Physiology
- Cell Biology