Menon N K, Saito T, Wolf A, Bing R J
Department of Experimental Cardiology, Huntington Medical Research Institutes, Pasadena, CA 91105.
Life Sci. 1989;44(9):611-8. doi: 10.1016/0024-3205(89)90193-8.
We demonstrated previously that 10(-5)M micellar solution of lysophosphatidylcholine (LPC) produced relaxation of rabbit thoracic aorta in a dose-dependent manner. It was also noticed that histamine (HA)-precontracted strips relaxed spontaneously in the absence of LPC. We now measured the cyclic GMP changes during these two types of relaxation. Results indicate that while LPC-induced relaxation was mediated through cyclic GMP, spontaneous relaxation was not. The vasodilating effect of LPC was not due to its interference with cellular viability by solubilizing the membrane, because repeated additions of LPC produced identical degrees of relaxation and after three consecutive additions of LPC, the strips continued to relax to the same degree with acetylcholine (Ach) demonstrating the functional integrity of the endothelium. LPC/Cholesterol dispersions (1:0.5 mole percent) relaxed the strips to the same extent as the micellar solution of LPC, while 1:1 mole percent did not. The results stress the role of cyclic GMP in LPC-induced relaxation. They further suggest that LPC/Cholesterol ratio may determine the availability of LPC and regulate LPC-mediated processes.
我们之前证明，10(-5)M溶血磷脂酰胆碱（LPC）的胶束溶液能使兔胸主动脉呈剂量依赖性舒张。还注意到，组胺（HA）预收缩的血管条在无LPC时会自发舒张。我们现在测量了这两种舒张过程中环状鸟苷酸（cGMP）的变化。结果表明，LPC诱导的舒张是通过cGMP介导的，而自发舒张则不是。LPC的血管舒张作用并非因其通过溶解膜而干扰细胞活力，因为重复添加LPC会产生相同程度的舒张，且在连续三次添加LPC后，血管条对乙酰胆碱（Ach）仍能以相同程度舒张，表明内皮功能完整。LPC/胆固醇分散体（1:0.5摩尔百分比）使血管条舒张的程度与LPC胶束溶液相同，而1:1摩尔百分比则不然。这些结果强调了cGMP在LPC诱导舒张中的作用。它们还进一步表明，LPC/胆固醇比例可能决定LPC的可用性并调节LPC介导的过程。
