Vascular Reactions in Septic Shock and Multiple Organ Failure

我们研究了冠状动脉旁路手术(CABG)患者的胃网膜动脉、乳内动脉和放射状动脉等人体动脉的血管反应。1)磷酸二酯酶(PDE)3抑制剂对人体不同血管组织的作用尚未进行系统的研究。我们的结果表明，这三种PDE3抑制剂在不同区域的人动脉中的活性不同。此外，这些药物对去甲肾上腺素和血栓素A_2等激动剂的收缩反应的抑制作用也不同。2)多巴胺对人冠状动脉旁路移植血管的直接作用尚不清楚。我们研究了它对冠状动脉搭桥术患者的桡动脉(RA)、胃网膜动脉(GEA)和乳内动脉(IMA)离体环的影响。我们的结果表明，药物对DA_1和α_1肾上腺素能受体的不同亲和力可能突显了其在这些动脉之间的不同收缩和血管松弛作用。3)我们研究了右美托咪定(DEX)对体外人阻力动脉的直接作用。从胃切除标本中分离胃网膜动脉，剥离血管内皮细胞，测定血管的机械反应。结果表明，地塞米松对人胃网膜动脉具有α_2-肾上腺素能激动剂和α_1-肾上腺素能拮抗剂双重作用。这些数据预测地塞米松在正常的临床条件下对血管反应性几乎没有直接影响，而在某些情况下，地塞米松的稳态血浆浓度一般小于10^-7&gt；M。然而，在较高的地塞米松浓度下观察到的直接α_2激动剂和α_1拮抗剂作用可能显著影响血管张力。

We investigated vascular reactions in human arteries, such as gastro-epiploic arteries, internal mammary arteries, and radial arteries, obtained from patients who were undergoing coronary artery bypass surgery(CABG).1)Systematic investigations of the actions of phosphodiesterase(PDE)3 inhibitors on different human vascular tissues have not been performed. Our results suggest different activities among the three PDE3 inhibitors in human arteries located in different regions. Moreover, these drugs differ in their potencies against the contractile responses to agonists such as NE and thromboxane A_2 in these arteries.2)The direct actions of dopamine on human arterial coronary bypass grafts are not well known. We investigated its effects on isolated rings cut from radial arteries(RA), gastroepiploic arteries(GEA), and internal mammary arteries(IMA) harvested from patients undergoing coronary artery bypass surgery. Our results suggest that differing affinities of the drug for DA_1- and α_1-adrenergic receptors may underline its variable contractile and vasorelaxing effects among these arteries.3)We investigated the direct effect of dexmedetomidine(DEX) on human resistance arteries in vitro. Gastroepiploic arteries were isolated from the omentum of gastrectomy specimens, the vascular endothelium was denuded, and the smooth muscle mechanical responses were measured. Our results indicate that DEX has dual α_2-adrenergic agonist and α_1-adrenergic antagonist actions in human isolated gastroepiploic arteries. The data presented here predict that DEX would have little direct effect on vascular reactivity under normal clinical conditions where steady-state plasma levels of DEX are generally less than 10^<-7> M. However, the direct α_2 agonist and α_1 antagonist actions observed with higher concentrations of DEX could significantly affect vascular tone under certain conditions.