Neural control of skeletal muscle small arteries in the cat

我们假设激活骨骼肌的交感胆碱能神经导致小动脉扩张（内径100-500mum）。本研究的目的是1)研究麻醉猫在刺激下丘脑后部时胆碱能血管舒张发生的血管部位，2)检查内皮源性松弛因子一氧化氮是否在胆碱能血管舒张中起作用。用多普勒血流探头测量股骨血流速度（FBV）。股远端尾动脉有下行分支供应肱三头肌表面肌。利用x线电视血管造影，通过注射造影剂，观察股尾远端动脉（100-500mum）和肱三头肌表面小动脉（100-500mum）。下丘脑刺激时，动脉压、FBV和股血管电导升高15<正负bbb8mmhg（平均<正负>se）， 146<正负>25%,139<正负>25%。在刺激过程中，股骨尾侧远端动脉内径没有改变，但血流速度增加。相比之下，在下丘脑刺激期间，肱三头肌表面肌小动脉内径增加了55<±>.3 %，阿托品或切断坐骨神经可以消除这种内径。内径的增加被一氧化氮的合成抑制剂所钝化。综上所述，交感胆碱能神经刺激骨骼肌引起内径100-500mum的小动脉扩张，部分由nit介导

We hypothetized that activation of sympathetic cholinergic nerves to skeletal muscle causes a dilation of small arteries (internal diameter, 100-500mum). The aim of this study was 1) to study the vascular site at which the cholinergic vasodilation occurs during stimulation of posterior hypothalamus in anesthetized cats, and 2) to examine if endothelium-derived relaxing factor, nitric oxide, plays a role in cholinergic vasodilation. Femoral blood flow velocity (FBV) was measured with a Doppler flow probe. The distal caudal femoral artery has descending branches that supply the triceps surae muscle. Using and X-ray TV angiography, the distal caudal femoral artery (>500mum) and small arteries (100-500mum) in the triceps surae muscle was visualized by i.a. injecting a contrast medium. Arterial pressure, FBV,and femoral vascular conductance rose 15<plus-minus>8mmHg (mean<plus-minus>SE), 146<plus-minus>25%, and 139<plus-minus>25% during hypothalamic stimulation. The internal diameter of the distal caudal femoral artery did not alter during stimulation but the blood flow velocity was increased. In contrast, the internal diameter of small arteries in the triceps surae muscle increased 55<plus-minus>3% during hypothalamic stimulation, which was abolished by atropine or by cutting the sciatic nerve. The increase in internal diameter was blunted by a synthesis inhibitor of nitric oxide. It is concluded that stimulation of sympathetic cholinergic nerves to skeletal muscle causes a dilation of small arteries with internal diameter of 100-500mum, which is partly mediated by nit