Cavarape Alessandro, Endlich Nicole, Assaloni Roberta, Bartoli Ettore, Steinhausen Michael, Parekh Niranjan, Endlich Karlhans
Department of Experimental and Clinical Pathology and Medicine (DPMSC), University of Udine, Udine, Italy.
J Am Soc Nephrol. 2003 Jan;14(1):37-45. doi: 10.1097/01.asn.0000039568.93355.85.
In addition to intracellular calcium, which activates myosin light chain (MLC) kinase, MLC phosphorylation and hence contraction is importantly regulated by MLC phosphatase (MLCP). Recent evidence suggests that distinct signaling cascades of vasoactive hormones interact with the Rho/Rho kinase (ROK) pathway, affecting the activity of MLCP. The present study measured the impact of ROK inhibition on vascular F-actin distribution and on vasoconstriction induced by activation/inhibition of distinct signaling pathways in vivo in the microcirculation of the split hydronephrotic rat kidney. Local application of the ROK inhibitors Y-27632 or HA-1077 induced marked dilation of pre- and postglomerular vessels. Activation of phospholipase C with the endothelin ET B agonist IRL 1620, inhibition of soluble guanylyl cyclase with 1H-[1,2,4]oxadiazolo-[4,3-a]quinoxalin-1-one (ODQ), or inhibition of adenylyl cyclase with the adenosine A1 agonist N6-cyclopentyladenosine (CPA) reduced glomerular blood flow (GBF) by about 50% through vasoconstriction at different vascular levels. ROK inhibition with Y-27632 or HA-1077, but not protein kinase C inhibition with Ro 31-8220, blunted ET B-induced vasoconstriction. Furthermore, the reduction of GBF and of vascular diameters in response to ODQ or CPA were abolished by pretreatment with Y-27632. ROK inhibitors prevented constriction of preglomerular vessels and of efferent arterioles with equal effectiveness. Confocal microscopy demonstrated that Y-27632 did not change F-actin content and distribution in renal vessels. The results suggest that ROK inhibition might be considered as a potent treatment of renal vasoconstriction, because it interferes with constriction induced by distinct signaling pathways in renal vessels without affecting F-actin structure.
除了可激活肌球蛋白轻链（MLC）激酶的细胞内钙外，MLC磷酸化以及由此产生的收缩还受到MLC磷酸酶（MLCP）的重要调节。最近的证据表明，血管活性激素的不同信号级联与Rho/Rho激酶（ROK）途径相互作用，影响MLCP的活性。本研究在肾积水大鼠肾脏微循环中，测量了ROK抑制对体内不同信号通路激活/抑制所诱导的血管F-肌动蛋白分布和血管收缩的影响。局部应用ROK抑制剂Y-27632或HA-1077可引起肾小球前和肾小球后血管的明显扩张。用内皮素ETB激动剂IRL 1620激活磷脂酶C、用1H-[1,2,4]恶二唑并-[4,3-a]喹喔啉-1-酮（ODQ）抑制可溶性鸟苷酸环化酶或用腺苷A1激动剂N6-环戊基腺苷（CPA）抑制腺苷酸环化酶，可通过不同血管水平的血管收缩使肾小球血流量（GBF）减少约50%。用Y-27632或HA-1077抑制ROK，但用Ro 31-8220抑制蛋白激酶C则不能减弱ETB诱导的血管收缩。此外，Y-27632预处理可消除ODQ或CPA引起的GBF和血管直径的减小。ROK抑制剂对肾小球前血管和出球小动脉的收缩具有同等有效的预防作用。共聚焦显微镜显示，Y-27632不会改变肾血管中F-肌动蛋白的含量和分布。结果表明，ROK抑制可能被视为一种有效的肾血管收缩治疗方法，因为它可干扰肾血管中不同信号通路诱导的收缩，而不影响F-肌动蛋白结构。
