Damasceno William Coutinho, Pires Washington, Lima Milene Rodrigues Malheiros, Lima Nilo Resende Viana, Wanner Samuel Penna
Exercise Physiology Laboratory, Department of Physical Education, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
Exercise Physiology Laboratory, Department of Physical Education, School of Physical Education, Physiotherapy and Occupational Therapy, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
Neurosci Lett. 2015 Mar 17;590:193-8. doi: 10.1016/j.neulet.2015.01.082. Epub 2015 Feb 2.
Evidence has shown that brain and abdominal (T abd) temperatures are regulated by distinct physiological mechanisms. Thus, the present study examined whether central cholinergic stimulation would change the dynamics of exercise-induced increases in T abd and thalamic temperature (T thal), an index of brain temperature. Adult male Wistar rats were used in all of the experiments. Two guide cannulae were implanted in the rats, one in the thalamus and the other in the right lateral cerebral ventricle, to measure T thal and to centrally inject a cholinergic agonist, respectively. Then, a temperature sensor was implanted in the abdominal cavity. On the day of the experiments, the rats received an intracerebroventricular injection of 2 μL of 10(-2)M physostigmine (Phy) or a vehicle solution (Veh) and were subjected to treadmill running until volitional fatigue occurred. T thal was measured using a thermistor connected to a multimeter, and T abd was recorded by telemetry. Phy injection delayed the exercise-induced increases in T thal (37.6 ± 0.2°C Phy vs 38.7 ± 0.1°C Veh at the 10th min of exercise) and in T abd. Despite the delayed hyperthermia, Phy did not change the rats' physical performance. In addition, the more rapid exercise-induced increase in T thal relative to Tabd in the rats treated with Veh was abolished by Phy. Collectively, our data indicate that central cholinergic stimulation affects the dynamics of exercise-induced increases in T thal and T abd. These results also provide evidence of the involvement of cholinoceptors in the modulation of brain heat loss during physical exercise.
有证据表明，大脑和腹部（T abd）温度受不同的生理机制调节。因此，本研究探讨了中枢胆碱能刺激是否会改变运动诱导的T abd和丘脑温度（T thal，脑温指标）升高的动态变化。所有实验均使用成年雄性Wistar大鼠。在大鼠体内植入两根引导套管，一根置于丘脑，另一根置于右侧侧脑室，分别用于测量T thal和向中枢注射胆碱能激动剂。然后，在腹腔内植入一个温度传感器。在实验当天，大鼠接受脑室内注射2 μL 10(-2)M毒扁豆碱（Phy）或溶剂（Veh），并进行跑步机跑步直至出现自愿疲劳。使用连接到万用表的热敏电阻测量T thal，通过遥测记录T abd。Phy注射延迟了运动诱导的T thal升高（运动第10分钟时，Phy组为37.6 ± 0.2°C，Veh组为38.7 ± 0.1°C）和T abd升高。尽管体温升高延迟，但Phy并未改变大鼠的身体表现。此外，Phy消除了Veh处理的大鼠中运动诱导的T thal相对于T abd更快升高的现象。总体而言，我们的数据表明中枢胆碱能刺激会影响运动诱导的T thal和T abd升高的动态变化。这些结果也为胆碱能受体参与体育锻炼期间脑散热调节提供了证据。
