Calcium and Sodium Inward Currents

In experiments using oxidant stress induced by the photoactivation of rose bengal (10 nM), a 75% decline in the calcium inward current was observed after 10 min, with only a sUght acceleration in the inactivation kinetics of the current (Shattock etal., 1990). However, this decline in the calcium inward current appears to occur secondary to an oxidant stress-induced calcium overload and not as 

The studies of Bhatnager et al. (1990) and Beresewicz and Horackova (1991) also report a significant and important increase in the inward movement of Na through the TTX-sensitive Na channel in cells exposed to oxidant stress. It is likely that this increased inward current may play a role in prolonging the action potential and in loading the cell with sodium. Both of these effects would combine to create a situation that would tend to load the cell with calcium through alteration in the activity of the Na/Ca exchange mechanism (Matsuura et al., 1991). 

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