Microdialysis with on-line chemiluminescence detection for the study of nitric oxide release in rat brain following traumatic injury

An on-line method was developed for the real-time detection of nitric oxide (NO) release in rat brain in vivo following traumatic injury by coupling microdialysis sampling to flow-injection chemiluminescence (CL) detection. The NO released from rat cerebellum was detected based on the CL reaction of luminol and H2O2 with a detection limit of 1nmoll-1. The perfusate flow was set at 5µlmin-1 in order to minimize NO loss before reaching CL detector. With this flow rate, about 5s was required for the solution to pass through the membrane of microdialysis probe to the detector due to the dead volume of the probe and CL cell. It was observed that the efficiency of NO penetrated from rat cerebellum into perfusate stream increased along with decrease of perfusate flow rate. The maximum efficiency of 20% could be achieved at the flow rate of 5µlmin-1 with carefully home-made microdialysis probe. The developed method was applied to the study of the production of NO in rat cerebellum following the traumatic brain injury. The results indicated that the NO increased dramatically following traumatic brain injury and was inhibited after the injection of inhibitors such as Larginine.