Age dependent L-type Ca²⁺ current distributions in intact single wt, mdx and MinD fibres.

<p>A, Representative i_Ca recordings in young (2–3 months) and aged (12–18 months) single wt, mdx and MinD fibres. In the 2–3 months old mdx fibre, the current amplitudes are markedly reduced. In aged mdx mice, a second fibre type appears with i_Ca amplitudes similar to wt and MinD fibres. B, Age dependent distribution of i_max amplitudes for age-matched wt, mdx and MinD fibres. In younger mdx fibres, i_max values were considerably smaller than in wt or MinD fibres of age-matched littermates. In older mdx fibres, some fibres (‘wt-like’ mdx fibres) displayed i_max values similar to those found in wt or MinD fibres while the rest (‘mdx-like’ mdx fibres) still had small i_max values similar to younger mdx fibres.