de Graaff Jurgen C, Ubbink Dirk T, Lagarde Sjoerd M, Jacobs Michael J H M
Department of Vascular Surgery, Academic Medical Center, 1100 DE Amsterdam, The Netherlands.
J Appl Physiol (1985). 2003 Dec;95(6):2223-8. doi: 10.1152/japplphysiol.00210.2003. Epub 2003 Jul 18.
Capillary circulation is delicately regulated by microvascular constriction mechanisms, thereby controlling capillary perfusion and transmural pressure. The influence of posture on capillary flow has been investigated in both diseased and healthy people. However, its influence on capillary pressure has rarely been investigated. We measured capillary pressures in the supine and sitting positions in the hallux of healthy volunteers. The capillaries in the eponychium of the hallux were punctured by using a micropipette connected to a micropressure system (900A, WPI). Also, peripheral arterial and venous pressures were measured in both positions. The rise in systolic capillary pressure from supine to sitting position (32 mmHg; from 39 to 71 mmHg, respectively) was significantly (P < 0.001) smaller than the rise in systolic arterial toe pressure (57 mmHg, from 87 to 144 mmHg, respectively) and venous pressure (41 mmHg, from 26 mmHg to 67 mmHg, respectively). This study shows that the postural rise in precapillary arteriolar pressure is not completely transmitted to the capillaries, probably because of activation of peripheral vasoconstriction mechanisms.
毛细血管循环由微血管收缩机制精细调节，从而控制毛细血管灌注和跨壁压力。姿势对毛细血管血流的影响已在患病和健康人群中进行了研究。然而，其对毛细血管压力的影响却鲜有研究。我们测量了健康志愿者拇趾在仰卧位和坐位时的毛细血管压力。使用连接到微压力系统（900A，WPI）的微量移液器穿刺拇趾甲上皮中的毛细血管。此外，还测量了两个体位下的外周动脉和静脉压力。从仰卧位到坐位，收缩期毛细血管压力的升高（32 mmHg；分别从39 mmHg升至71 mmHg）显著（P < 0.001）小于收缩期动脉趾部压力的升高（57 mmHg，分别从87 mmHg升至144 mmHg）和静脉压力的升高（41 mmHg，分别从26 mmHg升至67 mmHg）。这项研究表明，毛细血管前小动脉压力的姿势性升高并未完全传递至毛细血管，这可能是由于外周血管收缩机制的激活所致。
