Estrogen can regulate a variety of physiological functions and brain is one of its targets.Studies have shown that estrogen regulation of T-type calcium channel activity in the barin by binding to its receptors.The lateral habenula (LHb) serves as an important connection point linking the limbic system and the midbrain, and it participates in many physiological functions.Some regulating functions of LHb are believed to be estrogendependent, such as increase the sexual receptivity and maternal behavior during pregnancy and postpartum.LHb contained estrogen receptor, and also expressed a higher density of T-type calcium channels subtypes, Cav3.1 and Cav3.3, which play an important role in regulation neuronal excitability.We hypothesized that estrogen may affect the LHb neurons function by regulating the activation of T-type calcium channels.In this study, we determined the effect of estrogen on T-type calcium current in LHb neurons using patch clamp techniques in ovariectomized rats.We evaluated the expression of T-type calcium channels protein and mRNA using western blot and real-time PCR,respectively.We found that compared to control (oil-treated) group, mRNA and protein expression levels of both Cav3.1 and Cav3.3 were significantly decreased in LHb of E2-treated group, Whole-cell patch recordings in LHb neurons revealed that E2 treatment significantly attenuated T-type current, increased decay time and recovery time of T-type calcium channels, and increased the slope factor of activation and inactivation curve.Taken together,these data indicate the impact of estrogen to LHb may be related to the altered activity ofT-type calcium channels.