高温环境下运动能力会降低，其原因之一是体温过高引起的运动性中枢疲劳。多巴胺（DA）是脑内兴奋性神经递质之一，其运动中浓度的改变会影响中枢疲劳。另外，DA神经元部分投射在参与体温调节的下丘脑视前区（PO/AH），作用热敏神经元，影响产热和散热效应，改变体温。因此，PO/AH内DA可能会影响高体温引起的运动性中枢疲劳，但其机制尚不明确。据此，本项目将观察不同药物的中枢内干预对运动中大鼠的脑内神经递质、体温调节反应及疲劳发生时间的影响，系统地阐明PO/AH内DA对高体温引起的运动性中枢疲劳的作用及其机制。具体研究包括：1.高温环境下全脑DA能通路的活性改变对运动性中枢疲劳的影响；2. 高温环境下PO/AH内DA能通路的活性改变对运动性中枢疲劳的影响。此项目将从神经生物学的角度阐明DA、体温调节反应及中枢疲劳的相互关系，为今后探索防止高温环境下运动能力下降的策略及方法奠定前期的科学理论基础。

Endurance exercise performance is impaired as ambient temperature increases. One physiological mechanisms that act to impair exercise performance in the heat is hyperthermia-induced central fatigue. Dopamine (DA) is one excited neurotransmitters, and changes of brain DA level have been shown to affect central fatigue. DA is in innervated areas of the preoptic area/anterior hypothalamus (PO/AH), and may excite the warm-sensitive neurons, affect heat production and heat loss responses, induce changes in core body temperature. Therefore, DA in the PO/AH may play an important role in hyperthermia induced central fatigue, but the mechanism remains elusive. Above all, the purpose of the present study will observe effects of different central pharmacological interventions in dopaminergic pathway on brain neurotransmitters, thermoregulation and timing fatigue in exercising rats for clarifying the mechanisms behind the effect of DA in the PO/AH on hyperthermia induced-central fatigue during exercise. The specific study contents are in the follows: 1. To examine effects of different pharmacological interventions of dopaminergic pathway in the total brain on central fatigue during exercise in the heat; 2. To examine effects of different pharmacological interventions of dopaminergic pathway in the PO/AH on central fatigue during exercise in the heat. This project is based on neurobiological perspective to clarify the relationship among DA in the PO/AH, thermoregulation and central fatigue during exercise in the heat, establish foundation of the scientific theory to explore strategies and methods for preventing impairment of exercise performance in the heat.