Figure 4.

Ovariectomy triggers BDNF-mediated NMDAR potentiation by the KCC2/STEP₆₁/SFK pathway in SDH neurons of female rats. (A) Ovariectomy (OVX) has no effect on baseline lamina I NMDAR mEPSCs of female SD rats. Left: Saline-treated naïve female versusOVX female lamina I neurons, created using BioRender.com. Middle: Average mEPSCs at +60 mV in lamina I neurons of naïve (purple) and ovariectomized (lilac) female rats. Right: Peak amplitude (compared using Mann–Whitney test), decay constant (compared using independent samples t-test) and charge transfer (compared using independent samples t-test) of the NMDAR component of mEPSCs do not differ between naïve (n = 10) and OVX (n = 8) female rats. (B) In OVX rats, NMDAR mEPSCs in lamina I neurons are potentiated following ex vivo BDNF treatment. This potentiation is blocked using co-treatment with the SFK inhibitor, PP2. Left: Recordings from lamina I neurons were compared for saline- versus BDNF-treated slices from OVX rats, created using BioRender.com. Middle: Average mEPSCs at +60 mV from OVX female rat lamina I neurons; control in black, BDNF in purple, BDNF+PP2 in blue. Right: Charge transfer of NMDAR mEPSCs shown on left. n = 8 for control, n = 9 for BDNF and BDNF + PP2. Comparisons were made using one-way ANOVA, followed by Tukey HSD when P < 0.05. (C) Ex vivo BDNF treatment in OVX rat SDH synaptosomes results in upregulation of pY⁴²⁰Fyn and downregulation of KCC2 and STEP₆₁. Plots (left) and representative western blots (right) from OVX female rat SDH synaptosomes of tissue treated with either control saline (lilac, n = 8) or 50 ng/ml recombinant BDNF for 70 min (purple, n = 8, compared using paired samples t-tests). *P < 0.05.