Koskinen L O, Bill A
Acta Physiol Scand. 1984 Oct;122(2):127-36. doi: 10.1111/j.1748-1716.1984.tb07490.x.
The effects of TRH on regional blood flow were studied in rabbits under urethane anesthesia. Four types of experiments were performed with the following results. (1) I.v. injection of 2 mg/kg b.w. TRH in animals with unilateral cervical sympathotomy caused a rise in mean arterial blood pressure from 10.0 +/- 0.5 to 13.3 +/- 0.5 kPa. Total cerebral blood flow, measured with labeled microspheres, increased from 75 +/- 5 to 126 +/- 16 g/min/100 g tissue on the intact side. There was a similar increase on the side with sympathotomy. The greatest increase, about 70%, was observed in cortical gray matter, caudate nucleus and thalamic region. There were marked reductions in blood flows in the spleen, gastric mucosa, skin and skeletal muscle. Mydriasis occurred on the side with an intact sympathetic supply. (2) I.v. infusion of 0.06 mg/kg b.w. per min TRH in animals with unilateral cervical sympathotomy and stabilized blood pressure increased total cerebral blood flow from 84 +/- 10 to 139 +/- 7 g/min/100 g. Blood flows to the masseter muscle, submandibular gland and facial skin but not to the eye or tongue were markedly reduced on the side with an intact sympathetic supply while little or no effect was observed on the side with sympathotomy. (3) Unilateral peripheral stimulation of the sympathetic chain at 1 Hz after bilateral sympathotomy caused a reduction in blood flows in the tongue, masseter muscle, submandibular gland and facial skin in animals with stabilized blood pressure. No potentiation of the stimulation effect was observed during TRH infusion. (4) The arteriovenous difference in oxygen saturation in the brain decreased from 39.1 +/- 2.8 to 26.4 +/- 3.7% after i.v. injection of 2 mg/kg b.w. TRH. The results indicate that TRH caused cerebral vasodilation in excess of that required by possible changes in cerebral metabolism. The vasoconstriction in the head region and the mydriasis was caused mainly by an increase in the activity of the cervical sympathetic nerves.
在氨基甲酸乙酯麻醉的家兔身上研究了促甲状腺激素释放激素（TRH）对局部血流的影响。进行了四种类型的实验，结果如下：（1）给单侧颈交感神经切断的动物静脉注射2mg/kg体重的TRH，平均动脉血压从10.0±0.5kPa升至13.3±0.5kPa。用标记微球测量的全脑血流量，完整侧从75±5g/min/100g组织增加到126±16g/min/100g组织。交感神经切断侧也有类似增加。在皮质灰质、尾状核和丘脑区域观察到最大增加，约70%。脾脏、胃黏膜、皮肤和骨骼肌的血流量明显减少。交感神经供应完整侧出现瞳孔散大。（2）给单侧颈交感神经切断且血压稳定的动物以每分钟0.06mg/kg体重的速度静脉输注TRH，全脑血流量从84±10g/min/100g增加到139±7g/min/100g。交感神经供应完整侧咬肌、下颌下腺和面部皮肤的血流量明显减少，但眼或舌的血流量未减少，而交感神经切断侧几乎没有影响。（3）双侧交感神经切断后，以1Hz频率单侧外周刺激交感神经链，使血压稳定的动物舌、咬肌、下颌下腺和面部皮肤的血流量减少。在输注TRH期间未观察到刺激效果增强。（4）静脉注射2mg/kg体重的TRH后，脑内动静脉氧饱和度差从39.1±2.8%降至26.4±3.7%。结果表明，TRH引起的脑血管舒张超过了脑代谢可能变化所需的程度。头部区域的血管收缩和瞳孔散大主要是由颈交感神经活动增加引起的。
