| Objective: This study is designed to investigate the cardiovascular function characteristics and their relation to the activity of rostral ventrolateral medulla(RVLM)and nucleus accumbens(NAc)or thalamic reticular nucleus(TRN)neurons in anorexia nervosa(AN)model rats.Moreover,preliminary analysis of the possible connections between the nuclei and exploring the possible mechanisms of cardiovascular function changes in anorexia nervosa model rats provide theoretical basis and new ideas for the prevention and treatment of anorexia nervosa.Methods: Adult male SD rats were randomly divided into normal control group and anorexia nervosa model group.One week after adaptive feeding,the simulation method of diet and exercise was used to prepare anorexia nervosa model for 21 days.The successful preparation of the model rats was judged by observing the body weight and food intake of the model rats.When the body weight is lower than 25% of the body weight of normal-fed rats,and the comparison between the groups is statistically significant,it can be regarded as a successful preparation of the anorexia nervosa model.After the model was successfully prepared,the two groups of rats were given intraperitoneal injection of mixed anesthesia,then the femoral artery was intubated,and the instrument for recording the basic physiological indexes was connected with the rat.The femoral blood pressure,electrocardiogram,body temperature and respiratory muscle electromyogram in rats were simultaneously recorded by using the Powerlab multi-channel simultaneous recording system.The central nucleus of the rat is positioned by a brain stereotaxic instrument.The skull of the rat was fully exposed,and the glass electrode filled with the electrode liquid was slowly down-regulated to the corresponding nuclear position and depth for neuronal discharge recording.Results: 1.Preparation of anorexia nervosa rat model:The body weight data of the model group and the control group rats were recorded periodically.After the modeling phase,the data of the two groups were analyzed and compared.The body weight of the model group rats was 25% lower than that of the normal feeding rats(P < 0.05),indicating that the rat model of anorexia nervosa can be successfully prepared.2.Peripheral cardiovascular function indexes and central RVLM and NAc neuron firing in anorexia nervosa model rats were recorded simultaneously:Synchronous recordings of femoral blood pressure,electrocardiogram,body temperature,respiratory muscle electromyogram,and RVLM and NAc neuron discharge were performed in 10 normal control rats and 13 anorexia nervosa model rats,respectively.Compared with the control group,the mean arterial pressure(MAP)of AN model group rats was significantly lower(P < 0.05),and the heart rate(HR)and body temperature decreased significantly(P < 0.01).The discharge frequency of RVLM and NAc neurons in the AN model group was significantly higher than that in the control group(P < 0.01).Other physiological indicators such as LF/HF of heart rate variability(HRV)had a decreasing trend.There was no significant difference in systolic pressure,diastolic pressure and respiratory muscle myoelectric frequency between the two groups.3.Peripheral cardiovascular function indexes and central RVLM and TRN neuron firing were recorded synchronously in the anorexia nervosa model rats:Synchronous recordings of femoral blood pressure,electrocardiogram,body temperature,respiratory muscle electromyogram,and RVLM and TRN neuron discharge were performed in 9 normal control rats and 17 anorexia nervosa model rats,respectively.Compared with the control group,the MAP of AN model group rats was significantly lower(P < 0.05),the discharge frequency of RVLM and TRN neurons in AN model group were significantly higher than that in the control group(P < 0.01),and other physiological indexes,such as HR,LF/HF of HRV,systolic pressure,diastolic pressure,respiratory muscle myoelectric frequency,temperature had no statistical difference between the two groups.Conclusion: The results of this experiment suggest that:(1)The anorexia nervosa rat model can be successfully prepared by diet-exercise simulation method.(2)Cardiovascular function in rats with anorexia nervosa is weakened.(3)RVLM,NAc or TRN neuronal activity may be involved in the regulation of cardiovascular function in rats with anorexia nervosa. |
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