Bretschneider E, Paintz M, Glusa E
Jena University, Center for Vascular Biology and Medicine, Erfurt, Germany.
Biochem Pharmacol. 1995 Jan 6;49(1):33-8. doi: 10.1016/0006-2952(94)00404-a.
The role of the intracellular messengers inositol 1,4,5-triphosphate (IP3) and protein kinase C (PKC) in the thrombin (3 U/mL)-induced contraction of endothelium-denuded porcine pulmonary arteries was investigated. Thrombin induced a sustained contractile response with an initial transient increase in IP3 to about 160% of the unstimulated control. Omission of extracellular Ca2+ or preincubation with verapamil (10 mumol/L) reduced the maximum of contraction without significantly affecting the thrombin-induced increase in IP3. To evaluate the role of PKC for the contractile response, the PKC was activated directly by phorbol 12,13-dibutyrate (PDBu, 50 nmol/L). The phorbol ester produced a slowly increasing tonic contraction without any changes in the basal IP3 level. There was a moderate inhibition of PDBu-induced contractions in Ca(2+)-free solution, while they were not inhibited after preincubation with verapamil. Preincubation with the PKC inhibitor staurosporine (50 nmol/L) significantly reduced the PDBu-induced contraction (by about 80%). In thrombin-stimulated vessels staurosporine only inhibited the tonic phase of the contractile response whereas the increase in IP3 and the phasic component of contraction were still evident. These results suggest that IP3 and PKC are involved in the thrombin-induced contraction. The phasic component of contraction is associated with the generation of IP3; the tonic component might be due to the activation of PKC.
研究了细胞内信使肌醇1,4,5 -三磷酸（IP3）和蛋白激酶C（PKC）在凝血酶（3 U/mL）诱导的去内皮猪肺动脉收缩中的作用。凝血酶诱导了持续的收缩反应，IP3最初短暂增加至未刺激对照的约160%。去除细胞外Ca2+或用维拉帕米（10 μmol/L）预孵育可降低收缩的最大值，而不显著影响凝血酶诱导的IP3增加。为了评估PKC在收缩反应中的作用，用佛波醇12,13 -二丁酸酯（PDBu，50 nmol/L）直接激活PKC。佛波醇酯产生缓慢增加的强直收缩，基础IP3水平无任何变化。在无Ca2+溶液中，PDBu诱导的收缩有中度抑制，而用维拉帕米预孵育后则无抑制作用。用PKC抑制剂星形孢菌素（50 nmol/L）预孵育可显著降低PDBu诱导的收缩（约80%）。在凝血酶刺激的血管中，星形孢菌素仅抑制收缩反应的强直期，而IP3的增加和收缩的相性成分仍然明显。这些结果表明，IP3和PKC参与了凝血酶诱导的收缩。收缩的相性成分与IP3的产生有关；强直成分可能是由于PKC的激活。
