Dhillon H S, Carman H M, Prasad R M
Department of Surgery, University of Kentucky Chandler Medical Center, Lexington 40536-0084, USA.
Neurochem Res. 1999 Jun;24(6):751-5. doi: 10.1023/a:1020779413122.
Regional activities of phosphoinositide-specific phospholipase C (PLC) were measured after lateral fluid percussion (FP) brain injury in rats. The activity of PLC on phosphatidylinositol 4,5-bisphosphate (PIP2) in the rat cortex required calcium, and at 45 microM concentration it increased PLC activity by about ten-fold. The activity of PLC was significantly increased in the cytosol fraction in the injured (left) cortex (IC) at 5 min, 30 min and 120 min after brain injury. However, in the same site, increases were observed in the membrane fraction only at 5 min after brain injury. In both the contralateral (right) cortex (CC) and ipsilateral hippocampus (IH), the activity of PLC was increased in the cytosol only at 5 min after brain injury. These results suggest that increased activity of PLC may contribute to increases in levels of cellular diacylglycerol and inositol trisphosphate in the IC (the greatest site of injury), and to a smaller extent in the IH and CC, after lateral FP brain injury. It is likely that this increased PLC activity is caused by alteration in either the levels or activities of one or more of its isozymes (PLCbeta, PLCgamma, and PLCdelta) after FP brain injury.
在大鼠侧方液压冲击（FP）脑损伤后，测定了磷脂酰肌醇特异性磷脂酶C（PLC）的区域活性。大鼠皮层中PLC对磷脂酰肌醇4,5-二磷酸（PIP2）的活性需要钙，在45 microM浓度下，它使PLC活性增加约十倍。脑损伤后5分钟、30分钟和120分钟时，损伤（左侧）皮层（IC）的胞质溶胶部分中PLC的活性显著增加。然而，在同一部位，仅在脑损伤后5分钟时膜部分出现增加。在对侧（右侧）皮层（CC）和同侧海马体（IH）中，仅在脑损伤后5分钟时胞质溶胶中PLC的活性增加。这些结果表明，侧方FP脑损伤后，PLC活性增加可能导致损伤最严重部位IC中细胞二酰基甘油和肌醇三磷酸水平升高，在IH和CC中升高程度较小。FP脑损伤后，这种PLC活性增加可能是由其一种或多种同工酶（PLCβ、PLCγ和PLCδ）的水平或活性改变所致。
