Fig. 9.

Dependency of maternal diabetes-induced increase of AHP currents (I_AHP) and AHP on Ca²⁺influx in PCMNs. The I_AHP current and AHP were evoked and measured as in Fig. 8. In addition, AHP was evoked by a current injection of sufficient intensity to generate a single AP. The peak of AHP was measured at 10 and 50 ms. A: (control) and B (NMDM). The black trace is the I_AHP before Cd²⁺, and the gray trace is the I_AHP after Cd²⁺ application. A′ (control) and B′ (NMDM). The Cd²⁺–sensitive I_AHP was obtained by subtracting the current after Cd²⁺ from the current before Cd²⁺ application. The decay of Cd²⁺–sensitive I_AHP was fitted by a single exponential equation (red line). C: maternal diabetes significantly increased Cd²⁺–sensitive I_AHP (*P < 0.05) but did not increase decay time constant. D and E: representative AHP waveforms of control (D) and NMDM (E) PCMNs before and after Cd²⁺ application. F: Cd²⁺ significantly reduced AHP in both groups (†P < 0.05). After application of Cd²⁺, the AHP amplitude at 10 and 50 ms in NMDM was comparable to control, indicating that blockade of Ca²⁺influx completely abolished maternal diabetes-induced increase of AHP. In addition, maternal diabetes induced a significant greater reduction of AHP compared with control (*P < 0.05).