Figure 6. Indo-1 calcium transients elicited by depolarizing pulses at 0 mV of increasing duration in a control and in an mdx fibre from a batch of mice older than ≈35 weeks.

The mdx fibres from this batch displayed a significantly lower mean resting [Ca²⁺]_i than control ones. A, a series of indo-1 percentage saturation traces from a control (left) and an mdx fibre (right) in response to 5, 15 and 45 ms duration command pulses at 0 mV. The control and mdx fibre were from a 50- and a 41-week-old mouse, respectively. B, [Ca²⁺]_i transients calculated from the above corresponding indo-1 percentage saturation traces. The smooth curves superimposed on the decay of the [Ca²⁺]_i traces correspond to the results from fitting a single exponential plus constant function. The value of the corresponding time constant is indicated next to each trace.