Contextual Fear Learning and Extinction in the Primary Visual Cortex of Mice.

Fear memory contextualization is critical for selecting adaptive behavior to survive. Contextual fear conditioning (CFC) is a classical model for elucidating related underlying neuronal circuits. The primary visual cortex (V1) is the primary cortical region for contextual visual inputs, but its role in CFC is poorly understood. Here, our experiments demonstrated that bilateral inactivation of V1 in mice impaired CFC retrieval, and both CFC learning and extinction increased the turnover rate of axonal boutons in V1. The frequency of neuronal Ca2+ activity decreased after CFC learning, while CFC extinction reversed the decrease and raised it to the naïve level. Contrary to control mice, the frequency of neuronal Ca2+ activity increased after CFC learning in microglia-depleted mice and was maintained after CFC extinction, indicating that microglial depletion alters CFC learning and the frequency response pattern of extinction-induced Ca2+ activity. These findings reveal a critical role of microglia in neocortical information processing in V1, and suggest potential approaches for cellular-based manipulation of acquired fear memory.

Long-term microglial phase-specific dynamics during single vessel occlusion and recanalization.

Vascular occlusion leading to brain dysfunctions is usually considered evoking microglia-induced inflammation response. However, it remains unclear how microglia interact with blood vessels in the development of vascular occlusion-related brain disorders. Here, we illuminate long-term spatiotemporal dynamics of microglia during single vessel occlusion and recanalization. Microglia display remarkable response characteristics in different phases, including acute reaction, rapid diffusion, transition and chronic effect. Fibrinogen-induced microglial cluster promotes major histocompatibility complex II (MHCII) expression. Microglial soma represents a unique filament-shape migration and has slower motility compared to the immediate reaction of processes to occlusion. We capture proliferative microglia redistribute territory. Microglial cluster resolves gradually and microglia recover to resting state both in the morphology and function in the chronic effect phase. Therefore, our study offers a comprehensive analysis of spatiotemporal dynamics of microglia and potential mechanisms to both vessel occlusion and recanalization. Microglial phase-specific response suggests the morphological feature-oriented phased intervention would be an attractive option for vascular occlusion-related diseases treatments.

[Absorption characteristics of alkaloids in Fuzheng Xiaozheng Fang by rat everted intestinal sac models].

Everted intestinal sac models were used to investigate the intestinal absorption of the 4 alkaloids(berberine, palmatine, coptisine, and epiberberine) in Fuzheng Xiaozheng Fang(FZ) at different intestine segments. The absorption parameters of each component were calculated; SPSS 20.0 software was used to analyze the data and evaluate the absorption characteristics at different intestinal segments. The results showed that all the four active ingredients conformed to zero-order absorption rate. There was significant difference in absorption rate constant (Ka) between the four ingredients at low dose and medium and high dose groups(P<0.05), but there was no significant difference in Ka between medium dose and high dose. The absorption mechanization of four ingredients presented two absorption manners： positive diffusion and passive absorption. The absorptive amount of 4 alkaloids in ileum was slightly greater than that of jejunum, but no significant differences were observed, which indicated that these four alkaloids had no specific absorption windows in intestinal segment.