[Effects of Synaptotagmin1 gene knockout on the behavior of mice].

To study the effects of Synaptotagmin1 gene knockout (Syt1) on emotional behavior in mice and explore its possible mechanisms. Five 8-week-old male Syt1mice and five wild-type (WT) mice in the same litter were selected. The expressions of Syt1 in 6 mice brain regions of prelimbic cortex (PL), hippocampus (HIP), amygdala (AMY), accumbens nucleus (ACB), caudoputamen (CP) and ventral tegmental area (VTA) were detected by Immunofluorescence staining. Nine 8-week-old male Syt1mice and ten WT mice were selected as controls. The anxiety-like behaviors of adult Syt1 mice and WT mice were detected by open field test, elevated plus maze test and forced swim test. In addition, five 8-week-old male Syt1mice and five WT mice were selected to detect the glutamate content in prelimbic cortex, hippocampus and amygdala. Compared with WT mice, the number of Syt1 positive cells in PL, HIP, AMY, ACB, CP and VTA were decreased significantly in Syt1 mice (＜0.01); Syt1 mice had less total movement distance in open field test (＜0.01), more preference for peripheral area (＜0.01) and less desire to explore the central platform (＜0.01), while Syt1 mice preferred to stay in a closed and safe environment (＜0.01); the number (＜0.05) and the time spent in open-arm explorations (＜0.01) were reduced significantly; the immobile time of Syt1 mice was increased in the forced swim test (＜0.01). Meanwhile, the concentration of glutamate in the amygdala of Syt1 mice was increased significantly (＜0.01). Syt1 gene knockout leads to significant anxiety-like behavior in mice, which is deduced that related to the increase of glutamate content in the amygdala.