Acute Elevated Glucose Promotes Abnormal Action Potential-Induced Ca²⁺ Transients in Cultured Skeletal Muscle Fibers

Figure 4

Inhibition of ion channels known to modulate the excitable properties of skeletal muscle: impact on biphasic AP-transients on 5-day old cultured fibers challenged with elevated glucose. Representative time course of a biphasic AP-induced Ca²⁺ transient (left panels) measured in fibers challenged with elevated D-glucose (25 mM; 48 h.) before (black traces) and 10 minutes after (red traces) the treatment with gadolinium (100 μM) (a), apamin (1 μM) (b), and JZTX-III (1 μM) (c). Panels (d–f) are zoomed-in versions of the records shown in (a–c) to better appreciate biphasic responses before and after channel blockers addition. No significant changes in time course of the Ca²⁺ transient (i.e., interspike interval) were found in fibers challenged with 25 mM D-glucose-exposed fibers and treated with gadolinium ( fibers; , two-sample paired Student’s t-test), apamin ( fibers; , two-sample paired Student’s t-test), or JZTX-III ( fibers; , two-sample paired Student’s t-test), when compared to fibers challenged with D-glucose.

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