Sex Differences in Electrophysiological Properties of Mouse Medial Preoptic Area Neurons Revealed byIn VitroWhole-cell Recordings

Despite extensive characterization of sex differences in the medial preoptic area (mPOA) of the hypothalamus, we know surprisingly little about whether or how male and female mPOA neurons differ electrophysiologically, especially in terms of neuronal firing and behavioral pattern generation. In this study, by performing whole-cell patch clamp recordings of the mPOA, we investigated the influences of sex, cell type, and gonadal hormones on the electrophysiological properties of mPOA neurons. Notably, we uncovered significant sex differences in input resistance (male > female) and in the percentage of neurons that displayed post-inhibitory rebound (male > female). Furthermore, we found that the current mediated by the T-type Ca(2+)channel (I-T), which is known to underlie post-inhibitory rebound, was indeed larger in male mPOA neurons. Thus, we have identified salient electrophysiological properties of mPOA neurons, namelyI(T)and post-inhibitory rebound, that are male-biased and likely contribute to the sexually dimorphic display of behaviors.

Automated summary

This study revealed significant differences in the electrophysiological properties of mPOA neurons between males and females, with males showing higher input resistance and post-inhibitory rebound. Additionally, the current mediated by the T-type Ca(2+) channel was found to be larger in male mPOA neurons.