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本文研究脑室内微量注射促甲状腺素释放激素(TRH),对麻醉兔的心血管作用及其机制。微量注射TRH到第四脑室(4μg)和侧脑室(10μg)均引起平均动脉血压明显升高和心率减慢,后者是由于压力感受器反射性影响而不是TRH本身的作用。先用哌唑嗪(4μg)阻断中枢内α_1-肾上腺素受体。TRH的加压反应明显降低。微量注射TRH到侧脑室对心肌收缩时间间期(STI)无明显影响。此外,进一步研究了TRH对兔离体窦房结-心房肌条标本的影响,发现TRH对收缩力无明显影响,但对心率有直接的抑制作用。
This article studies the microinjection of thyrotropin-releasing hormone (TRH) into the ventricle and its cardiovascular mechanism in anesthetized rabbits. Microinjection of TRH into the fourth ventricle (4 μg) and lateral ventricle (10 μg) caused a marked increase in mean arterial blood pressure and heart rate, the latter due to baroreceptor reflex rather than TRH itself. First, prazosin (4 μg) was used to block the central α 1 -adrenoceptor. TRH pressure response was significantly reduced. Microinjection of TRH into the lateral ventricle had no significant effect on myocardial systolic time (STI). In addition, further study TRH rabbit isolated atrial node - atrial myometrial specimens found that TRH no significant effect on contractility, but the heart rate has a direct inhibitory effect.