结节乳头体在小鼠运动和摄食中的作用及机制研究

目的:探讨结节乳头体在小鼠运动和摄食中的作用及机制。方法:选择雄性ddy小鼠,180-200 g,通过单侧植入电极损毁TMN-E2区。采用荧光金逆行追踪方法检测小鼠Me5与TMN之间的神经纤维联系;采用免疫组化方法检测小鼠TMN中组氨酸脱羧酶(HDC)免疫反应阳性细胞数;采用旷场试验箱记录小鼠全天、夜间以及白天的自主活动和摄食摄水;采用PCR检测小鼠穹窿周和下丘脑外侧区的orexin m RNA的表达。结果:荧光金逆行追踪实验显示小鼠Me5可向TMN-E2发出神经纤维投射。单侧TMN损毁,两侧TMN中HDC反应阳性细胞显著减少(P0.05),且损毁侧比未损毁侧HDC免疫反应阳性细胞数减少(P0.05)。TMN损毁对小鼠24 h自主活动和摄食摄水无明显影响。单侧TMN损毁,小鼠从暗期到光期的自主活动和摄食摄水显著减少(P0.05)。单侧TMN损毁,小鼠正常昼夜活动摄食节律无显著改变。单侧TMN损毁,小鼠穹隆周和下丘脑外侧区白天的orexin m RNA表达显著减少(P0.05)。结论:Me5与TMN之间存在神经通路,该通路可能通过调节穹隆周区或下丘脑外侧区的orexin神经元的激活从而调控摄食及相关行为的昼夜节律。

A Study on the Role and Mechanism of Tuberomammillary Nucleus in the Locomotor Activity and Feeding of Mice

ABSTRACT Objective: Study on the role and mechanism of tuberomammillary nucleus in the locomotor activity and feeding of mice. Methods: The male ddy mice, 180-200 g, and implantation electrode was used to destroy the unilateral TMN-E2 area. Using Fluorogold retrograde tracing method, the neural connection between Me5 and TMN mice were detected; Immunohistochemistry method was used to record the histidine decarboxylase(HDC) immunoreactive cell number in TMN; The open field system was used to record the locomotor activitiey and food intake and water intake in 24 h, light and dark phases. PCR was used to record the expression of orexin mRNA in the peripheral fornix and the lateral hypothalamus of mice. Results: The fluorogold retrograde tracing experiment showed that the Me5 could send nerve fiber projection to TMN-E2 in mice.In unilateral lesioned TMN, the HDC response positive cells in both sides of TMN were significantly reduced (P<0.05), and the number of HDC immunoreactive cells in the lesioned side was lower than that on the undamaged side (P<0.05). Unilateral TMN lesion had no significant effect on the locomotor activitiey and food intake and water intake in 24 h. The locomotor activitiey and food intake and water intake of miceduring the dark phase before the onset of the light phasedecreased significantly after unilateral TMN lesion (P<0.05). There was no significant change in the normal circadian rhythms of day and night activity in mice with unilateral TMN lesion. The expression of orexin mRNA in the PFA and the lateral hypothalamus in the daytime of the unilateral TMN was significantly reduced (P<0.05). Conclusion: There is a neural pathway between Me5 and TMN. This pathway may regulate the circadian rhythm of feeding and related behaviors by regulating the activation of orexin neuron in the PFA and hypothalamus lateral area.