AIM：To investigate the roles of nitric oxide (NO) and endothelin-1(ET-1) in regulation of coronary vascular reserve (CVR) during hypoxia.METHODS： CVR were measured with 99m TC radiolabelled frog RBC, the changes of NO-2，ET-1 contents， nitric oxide synthase(NOS) activity and the myocardial morphometry were observed. RESULTS： (1) Acute hypoxia caused an increase in left and right ventricular myocardial blood flow，myocardial NO-2，ET-1 contents，NOS activity，but CVR in the left and right ventricle were decreased compared with the control group.(2) Intermittent hypobaric hypoxia for 90 days did not lead to significant change in left ventricular CVR，myocardial ET-1/NO-2 ratio. However, right ventricular myocardial ET-1 contents，ET-1/ NO-2 ratio were increased，right ventricular CVR and myocardial NO-2 contents were decreased. We also observed that perivascular collagen，arterial wall thickness in right ventricle， hematocrit，RV weight index were augmented. CONCLUSION： Rest myocardial blood flow was increased，CVR was decreased；The decreased coronary vascular reserve during chronic hypoxia might be resulted from the increased hematocrit，arterial wall thickness，perivascular collagen，ET-1 content, the decreased NO content and right ventricular hypertrophy

Objective To explore the relationship between field cognitive style and self-handicapping of medical students.Methods 124 medical students were measured by embedded figure test (EFT) and self-handicapping questionnaire (SHS).Results ①The scores of self-handicapping questionnaire were significantly different in whether they like their major or not(33.61±5.21,35.94±5.16,t=-0.218,P=0.031).Differences were also found in whether they could obtain the scholarships (33.20±6.19,35.12±4.12,t=-0.247,P=0.043),and in whether they were in a relationship(35.35±5.48,33.39±5.01,t=2.063,P=0.041).②Compared with field-independent cognitive style students,Field-dependent cognitive style students ' self-handicapping score was higher (35.69±3.91,32.63±6.08,t=3.303,P=0.001).③Field-dependent cognitive style,dislike their major and be in a relationship were the significant predictors of self-handicapping.Conclusion Correlation exists between field cognitive style and self-handicapping of the medical students.Students who belong to field-dependent cognitive style are more prone to self-handicapping than field-independent cognitive style students.

AIM: To explore the mechanism of ET-1, NO and PGI 2 release from coronary artery endothelial cells (CAEC) induced by acute hypoxia. METHODS: Bovine coronary artery endothelial cells were cultured and [ 45 Ca 2+ ] was used to investigate the difference of calcium uptake between normoxia group and hypoxia group (3% O 2). The contents of ET-1, NO and PGI 2 in media of normoxia group, hypoxia group and hypoxia + verapamil group were measured 24 h after hypoxia. RESULTS: [ 45 Ca 2+ ] uptake by CAEC in hypoxia group was 1.9 times more than normoxia group ( P

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.
Mice ; Animals ; Primary Visual Cortex ; Extinction, Psychological/physiology* ; Learning/physiology* ; Fear/physiology* ; Hippocampus/physiology*