Since (if I understand it) Richard's model involves a potential difference
between regions that are connected by a virtually perfect conductor (the
cytosol), I have difficulty seeing how Guy can be wrong that the influx of
cations at the plasma membrane raises the potential at the mitochondrial
membrane. But the inference that the mitochondrial delta-psi oscillates
by an amount similar to that at the plasma membrane may be wrong, if there
is a very rapid compensatory response that imports cations into the matrix.
I am currently rather enamoured of the ATP- (and also GTP-, GDP- and more)
sensitive potassium channel, which has been strongly implicated in the
homeostasis of mitochondrial volume (an important regulator of OXPHOS); it
also seems to stabilise delta-p, by adjusting the contributions of delta-pH
and delta-psi in response to changing cytosolic cation concentrations.
Czyz et al. 1995, BBRC 210:98-104 has details. Might it be involved here?
Aubrey de Grey
