Related Experiment Video
Updated: Aug 10, 2026

Wide-Field, Real-Time Imaging of Local and Systemic Wound Signals in Arabidopsis
Published on: June 4, 2021
Hyperpolarization-activated Ca2+-permeable channels in the plasma membrane of tomato cells
1Department of Botany, University of Toronto, 25 Willcocks Street, Toronto, Ontario, Canada M5S 3B2.
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 microM lanthanum and 50% inhibited by 100 microM nifedipine. This evidence suggests that hyperpolarization-activated Ca2+-permeable channels provide a mechanism for the influx of Ca2+ into tomato cells.
Related Concept Videos
Ion Channels
Ion channels are specialized integral membrane proteins on the plasma membrane that allow specific...
Non-gated Ion Channels
Compared to the gated ion channels, the non-gated channels, also known as leakage or passive channels, have no gating mechanism.
Voltage-gated Ion Channels
Generally, all voltage-gated ion channels have a 'voltage-sensing domain' that spans the lipid bilayer. The charged residues in the sensor move in response to the membrane potential changes that open the channel allowing ions movement. There are several types of...
Mechanically-gated Ion Channels
Cell Signaling in Plants
G-Protein Gated Ion Channels
Sensory organs,...

