Joannides R, Richard V, Moore N, Godin M, Thuillez C
Department of Pharmacology, Vaisseaux-Coeur-Medicament, Institut Fédératif de Recherches Multidisciplinaires sur les peptides, Rouen University Medical School, France.
Am J Physiol. 1995 Feb;268(2 Pt 2):H794-801. doi: 10.1152/ajpheart.1995.268.2.H794.
Although smooth muscle tone is a key determinant of mechanical properties of arteries in animal experiments, it has not yet been studied in humans because of technical limitations. To assess the influence of tone on arterial properties in humans and to emphasize the interest of calculation at specific stress, we used echo tracking and photoplethysmographic measurement of arterial pressure to study radial arterial mechanics during a cold pressor test (CPT) in 12 healthy volunteers (28 +/- 2 yr). During CPT, mean arterial pressure rose from 83 +/- 3 to 106 +/- 5 mmHg (P < 0.05), internal diameter decreased from 2.75 +/- 0.15 to 2.54 +/- 0.14 mm (P < 0.05), and wall thickness increased from 0.576 +/- 0.027 to 0.634 +/- 0.029 mm (P < 0.05). At a specific pressure (105 mmHg), midwall stress and incremental modulus decreased whereas arterial compliance increased. The incremental modulus of elasticity and compliance were fitted as functions of pressure and of midwall stress. CPT decreased the modulus about equally at all wall stresses measured. The modulus decreased and the compliance increased at every level of pressure measured. At all levels of midwall stress, the compliance was decreased. Thus acute sympathetic stimulation induced by CPT decreases the wall stiffness of human arteries in vivo. This may be explained by an unloading of stiffer wall components during active arterial constriction.
尽管在动物实验中，平滑肌张力是动脉力学特性的关键决定因素，但由于技术限制，尚未在人体中进行研究。为了评估张力对人体动脉特性的影响，并强调在特定应力下进行计算的意义，我们使用回声跟踪和光电容积描记法测量动脉压力，对12名健康志愿者（28±2岁）进行冷加压试验（CPT）时的桡动脉力学进行了研究。在CPT期间，平均动脉压从83±3 mmHg升至106±5 mmHg（P<0.05），内径从2.75±0.15 mm降至2.54±0.14 mm（P<0.05），壁厚从0.576±0.027 mm增加至0.634±0.029 mm（P<0.05）。在特定压力（105 mmHg）下，中膜应力和增量模量降低，而动脉顺应性增加。弹性增量模量和顺应性被拟合为压力和中膜应力的函数。在所有测量的壁应力下，CPT使模量降低的程度大致相同。在测量的每个压力水平下，模量降低，顺应性增加。在所有中膜应力水平下，顺应性均降低。因此，CPT诱导的急性交感神经刺激可降低人体动脉在体内的壁硬度。这可能是由于在动脉主动收缩期间，较硬的壁成分卸载所致。
