[The effects of prenatal stress on Ca2+ channel and K+ channel of hippocampal CA3 pyramidal neurons in rat offspring].

To investigate the effects of prenatal stress (PNS) on high-voltage-activated (HVA) Ca2+ channel and delayed rectifier potassium currents (I(KD)) of freshly isolated rat offspring hippocampal CA3 pyramidal neurons, the pregnant rats of PNS group were exposed to restraint stress and patch clamp technique of whole-cell mode was employed to record HVA Ca2+ and K+ channel currents in hippocampal CA3 pyramidal neurons. It was observed that PNS increased HVA calcium peak current amplitude. The maximal HVA calcium peak current amplitudes were -576.52 +/- 7.03 pA in the control group and -702.05 +/- 6.82 pA in the PNS group respectively (P < 0.01). The conductance-voltage relationship of HVA Ca2+ channel was not changed. Current-voltage relationship and conductance-voltage relationship of I(KD) in offspring CA3 neurons were also not affected by PNS. The data suggested that exposure of pregnant animals to a period of stress could impose lasting effects on the offspring hippocampus CA3 neurons Ca2+ channel during a critical phase of fetal development. The mechanism may include two ways. One was that high CORT led to enhance level of expression for the HVA Ca2+ channel subunit mRNAs and increased HVA calcium currents. Another was that PNS caused an increase in the production of ROS in hippocampal CA3 region and ROS caused an increase in the phosphorylation of HVA Ca2+ channel of offspring hippocampal CA3 neurons.