Takahashi S, Imagawa M, Mimata H, Nakagawa M, Ogata J, Nomura Y
Department of Urology, Oita Medical University, Hasama-machi, Japan.
Int J Urol. 1997 Jul;4(4):388-93. doi: 10.1111/j.1442-2042.1997.tb00213.x.
Platelet-activating factor (PAF) is a bioactive phospholipid which is a potent hypotensive agent. To investigate the role of PAF in renovascular hypertension, we determined the PAF concentration and its production level assessed by the activity of cholinephosphotransferase (CPT) in renal tissue and examined the effect of a PAF antagonist on the mean arterial pressure (MAP) in control and two-kidney with one clipped (2K1C) hypertensive rats.
The concentration of PAF and CPT in the renal medulla and cortex were determined by radioassay. Also, the effect of a PAF antagonist, CV-6209, on MAP was also examined in both 2K1C hypertensive and normal control rats.
The PAF concentration and CPT activity were significantly higher in the medulla than in the cortex in both 2K1C hypertensive and normal control rats, and both values in the medulla were also significantly higher in the clipped kidney than in the contralateral unclipped kidney or in control rat kidneys. We also observed a significant negative correlation between the PAF concentration in the medulla, and the medulla weight in the clipped kidney of 2K1C hypertensive rats. Infusion of the PAF antagonist, CV-6209, did not affect MAP in 2K1C hypertensive rats, but was significantly increased (P < 0.05) in control rats.
These findings suggest that PAF, whose production is induced by renal ischemia due to renal artery stenosis, plays an important role in the renomedullary vasodepressor system, but the effect of PAF as a vasodilator in the peripheral vessels is limited in 2K1C hypertension.
血小板活化因子（PAF）是一种生物活性磷脂，是一种强效降压剂。为了研究PAF在肾血管性高血压中的作用，我们测定了肾组织中PAF的浓度及其通过胆碱磷酸转移酶（CPT）活性评估的产生水平，并研究了PAF拮抗剂对正常大鼠和二肾一夹（2K1C）高血压大鼠平均动脉压（MAP）的影响。
通过放射测定法测定肾髓质和皮质中PAF和CPT的浓度。此外，还在2K1C高血压大鼠和正常对照大鼠中研究了PAF拮抗剂CV-6209对MAP的影响。
在2K1C高血压大鼠和正常对照大鼠中，髓质中的PAF浓度和CPT活性均显著高于皮质，并且夹闭肾中髓质的这两个值也显著高于对侧未夹闭肾或对照大鼠肾中的值。我们还观察到2K1C高血压大鼠夹闭肾中髓质PAF浓度与髓质重量之间存在显著负相关。输注PAF拮抗剂CV-6209对2K1C高血压大鼠的MAP没有影响，但在对照大鼠中MAP显著升高（P<0.05）。
这些发现表明，由于肾动脉狭窄导致肾缺血诱导产生的PAF在肾髓质血管减压系统中起重要作用，但在2K1C高血压中，PAF作为外周血管扩张剂的作用有限。
