To describe a case series in which corneal fluorescein staining (CFS) development occurred in short break-up time (s-BUT) dry eyes after a short period during prolonged opening of the eye.
We merely note that, as is well known, with prolonged opening Kv channels slowly become non-conductive, entering the so-called inactive state.
However, above a certain threshold, oxidative stress may induce a prolonged opening of the mitochondrial PTP, irreversibly committing cells to death.
Although transient mPTP opening is involved in cardioprotection, prolonged opening results in irreversible changes within cellular bioenergetics and cell death due to the release of proapoptotic factors (e.g., cytochrome c) [ 7, 25].
Indeed, the PTP is a voltage and Ca2+-dependent, CsA-sensitive, high conductance channel, whose prolonged opening leads to a brisk increase in the permeability of the inner mitochondrial membrane to solutes with molecular mass up to 1500 Da [19].
It is generally agreed that prolonged openings of the P2X7R pore is inevitably coupled to cell death.
Type I compounds prolong channel opening only long enough to cause repetitive firing of action potentials (repetitive discharge), whereas type II compounds hold open the channels for such long periods of time that the membrane potential ultimately becomes depolarized to the point at which generation of action potentials is not possible [depolarization-dependent block].
Type I compounds prolong channel opening just long enough to induce repetitive firing of action potentials (time constants less than 10 msec), whereas type II compounds (time constants of more than 10 msec) hold the channels open for so long that the membrane potential ultimately becomes depolarised to the point at which generation of action potentials is no longer possible (reviewed in [ 75]).
FPL is thought to modify LTCCs through prolonging their opening during depolarization and their inactivation upon repolarization, enhancing the duration of the consequent tail currents (Rampe & Lacerda 1991).
Like the more commonly used agonist Bay K, FPL prolongs the opening of single calcium channels during depolarization and slows channel closing upon repolarization.
