Effects of pregnancy on neuron electrophysiology in prefrontal cortex, hippocampus, and basolateral amygdala of mouse brain.

Abstract

Background: Pregnancy affects learning and memory in women. Thus, to investigate the effects of pregnancy, the authors examined the brain electrophysiology of pregnant mice.

Methods: Using the whole-cell patch-clamp technique on isolated brain slices, we detected and compared the electrophysiological changes in the hippocampal CA1 (HIP CA1) region, medial prefrontal cortex (mPFC), and basolateral amygdala (BLA) among 15 pregnant and 15 nonpregnant mice.

Results: In pregnant mice, there was a trend toward an increase in the frequency of miniature excitatory postsynaptic currents (mEPSCs) (p = 0.092) and a trend toward a decrease in the amplitude of miniature inhibitory postsynaptic currents (mIPSC) (p = 0.071) in the HIP CA1. In the BLA, both the amplitudes of mEPSCs and mIPSCs were significantly reduced (p = 0.004 and 0.042, respectively). In the mPFC, the amplitudes of mEPSCs and hyperpolarization-activated currents (Ih), as well as the frequencies of mIPSCs, were higher compared to nonpregnant mice (p = 0.035, 0.009, and 0.038, respectively).

Conclusions: In pregnant mice, the electrophysiological change in neurons in the mPFC and BLA might contribute to the cognitive and emotional changes during pregnancy. A trend toward electrophysiological change in the HIP CA1 revealed that the mechanism of cognitive change during pregnancy might differ from that of other conditions.