Fig. 8.
Maternal diabetes increased apamin afterhyperpolarization (AHP) currents (IAHP) and augmented the contribution of SK channels to AHP. IAHP current was evoked by a depolarizing voltage pulse of +10 mV (100 ms) from holding potential −70 mV followed by a returning −50 mV step. The peak of IAHP was measured. A (control) and B (NMDM). The black trace is the IAHP before apamin, and the gray trace is the IAHP after apamin. A′ (control) and B′ (NMDM). The apamin-sensitive IAHP was obtained by subtracting the current after apamin from the current before apamin. The decay of apamin IAHP was fitted by a single exponential equation (red line). C: maternal diabetes significantly increased apamin-sensitive IAHP (*P < 0.05) but did not change the decay time constant. D and E: representative AHP waveforms of control (D) and NMDM (E) PCMNs before and after apamin. F: apamin significantly reduced AHP in both groups (†P < 0.05). In addition, maternal diabetes induced a significant greater reduction of AHP compared with control (*P < 0.05).