The involvement of brainstem noradrenergic system in thermoregulation during exercise was evaluated by assessing the neuronal activation of A1, A2, locus coeruleus (LC) during exercise. Male Wistar rats weighing 280−330 g were used in the present study. Ninety minutes after exercise bout until fatigue, animals were anaesthesiated and brain removed and processed immunohistochemically for Fos protein and tyrosine hydroxylase in A1, A2 and LC and for Fos in POA subregions. Core and tail temperature were recorded during all running period by telemetry system. Heat storage rate (HSR, cal.min⁻¹), maximum tail vasoconstriction (°C) and vasodilatation threshold (°C) were calculated and correlated with Fos expression in all nuclei studied. Fos expression in LC correlated inversely with maximum tail skin vasoconstriction (r = −0.787, p < 0.03) and HSR (r = −0.834, p < 0.02) and positively to time to fatigue (r = 0.862, p < 0.01). A1 nucleus showed an inverse correlation with tail skin vasodilatation threshold (r = −0.861, p < 0.01). Fos expression in LC correlated inversely with Fos expression in the median (MnPO, r = −0.909, p < 0.01) and medial preoptic nucleus (MPOM, r = −0.942, p < 0.05). Our results bring further evidences that noradrenergic neurons from LC and A1 nuclei are involved in cutaneous heat loss mechanisms during exercise. LC nucleus probably modulates the sympathetic tonus of tail artery and integrates the central network LC / POA that could represent an important circuitry of temperature regulation during exercise. Also, noradrenergic neurons from A1 nucleus could be involved in cutaneous heat loss during exercise by modulating of vasodilatation threshold.

通过评估运动过程中 A1、A2、蓝斑 (LC) 的神经元激活来评估脑干去甲肾上腺素能系统在运动过程中参与体温调节。本研究中使用了体重为 280-330 克的雄性 Wistar 大鼠。运动后直至疲劳 90 分钟，对动物进行麻醉，取出大脑并对 A1、A2 和 LC 中的 Fos 蛋白和酪氨酸羟化酶以及 POA 亚区中的 Fos 进​​行免疫组织化学处理。通过遥测系统记录所有运行期间的核心和尾部温度。蓄热率（HSR，cal.min ^-1)，计算了最大尾部血管收缩 (°C) 和血管舒张阈值 (°C)，并与研究的所有细胞核中的 Fos 表达相关联。LC 中的 Fos 表达与最大尾部皮肤血管收缩（r = -0.787，p < 0.03）和 HSR（r = -0.834，p < 0.02）呈负相关，与疲劳时间呈正相关（r = 0.862，p < 0.01）。A1 核与尾部皮肤血管舒张阈值呈负相关（r = -0.861，p < 0.01）。LC 中的 Fos 表达与中位数 (MnPO, r = -0.909, p < 0.01) 和内侧视前核 (MPOM,r = -0.942，p < 0.05）。我们的研究结果进一步证明，来自 LC 和 A1 核的去甲肾上腺素能神经元参与运动过程中的皮肤散热机制。LC 核可能调节尾动脉的交感神经紧张，并整合中央网络 LC/POA，这可能代表运动期间温度调节的重要回路。此外，来自 A1 核的去甲肾上腺素能神经元可能通过调节血管舒张阈值参与运动过程中的皮肤热量损失。