Although monoamine neurotransmitters play a critical role in depression, our qRT-PCR results did not show significant changes in receptors 5-HT1A, 5-HT1B, DA-1, and DA-2 in OVX mice (Figures 7A–D), suggesting that monoamine neurotransmitters may not contribute to the pathogenesis of estrogen deficiency-induced depression. Here, HTR1A is linked to major depressive disorder.