Under stress, the outward channels are induced and inward channels are repressed.
In various mammalian cell types, AVD, which is mediated by water loss caused by activation of anion channels and a K+ outward rectifying channel, is an early prerequisite to apoptotic events including cell shrinkage, cytochrome c release, activation of proteases (including caspases) and nucleases, and ultimately PCD [39], [64].
However, the oscillatory dynamics at the tip will stay within a wide range of kinetic parameter values for the following transporters: K+ inward and outward rectifying channels, calcium channels at the tip.
Nitrergic self-inhibition also has features in common with nitrergic excitation of the MCC in Aplysia [7], in which NO via cGMP closes an outward leak channel, thereby depolarizing the MCC, rather than closing an inward leak channel and thereby polarizing B31/B32.
Delayed rectifier outward potassium channel (I K) is one of the most ubiquitously expressed voltage-gated K+ channels and plays many diverse physiological roles, due to its large conductance and slow inactivation properties.
Under high salinity, once Na+ has accumulated to toxic level in plants, plasma membrane depolarization occurs and activation of the outward K+ channel can lead to high Na+/K+ ratio (Cuin and Shabala 2007) and ion-specific toxicity, particularly in leaves (Munns and Tester 2008).
By removing the K+ outward rectifying channel at the shank our model shows that there would be no marked effect on ion concentrations and fluxes.
The type 2C protein phosphatases ABI1 and ABI2 [42], the outward potassium channel GORK [43] and the MYB transcription factor AtMYB61 [44] have functions in guard cell responses in the dark.
Outward single channel currents of various amplitudes were also observed at positive potentials (data not shown) suggesting the presence of further endogenous Na+ or Cl− permeabilities.
