| With the fast development of modern medicine, high quality and efficiency in drug screening and evaluation are required. Recently, high-throughput screening system is used for drug discovery. This system can screen compouds in a large scale by highly automatic equipments in cell level. The efficiency is much higher than traditional screening techniques. On the other hand, evaluations of drug effects in in vivo experiments, especially in evaluating the drugs that affect nervous and mental functions, should be improved in their objective, quantitative properties and efficiencies by the use of computer-assisted techniques. So, to establish new research systems for the central nervous drugs, it needs to resolve the high efficient screening in the cell level, and the objective, quantitative and efficient evaluating in in vivo experiments. Based on these requirements in new drug development and the equipments in our lab, we used a computer-assisted imaging analyzer to analyze the locomotor activities in an open field experiment, and developed a new model for evaluating central depressant drugs in mice. Furthermore, we established a model for evaluating neuroprotective drugs for neuron damage using 96 microplate culture. These experiments will contribute to new drug discovery system in the central nervous system in our lab.1. An objective and quantitative method in vivo: a new open-field experiment for evaluating central depressant drugs in miceLocomotor activities of mice in an open field box were observed, and the locomotor tracks within 30 min were recorded and analyzed by a computer imaging analyzer. The indexes used were total distance, the ratio of central time/total time, and the ratio of central distance/total distance. Pentobarbital was used as model drug, and its effects on locomotor properties were analyzed after ip injection at doses of 7.5, 15 and 30 mg.kg-1. Results showed that in the three strains of mice (ICR, NIH and KM), the total distance within the first 10 min was longer than those of the second and third 10 min durations (P< 0.01); and the activities in central region had only small differences but showed some strain and circadian differences. Pentobarbital reduced the total distance in ICR and NIH, but not in KM mice, but had no remarkable dose-dependency. However, pentobarbital reduced the ratios both central time and central distance dose-dependently in the three strains of mice. These results indicate that computer-assisted imaging analysis is a useful method for evaluating central depressant drugs with objective and quantitative properties.2. High-efficient evaluation in vitro: a model for evaluating neuroprotective drugs in cultured primary neuronsIn this study, 96-well microplates were used for cortical neuronal cultures from newborn rats at 10 days in vitro (DIV10). N-methyl-D-aspartate (NMDA) was used to induced neuron injury at different concentrations in different treatment durations with neuron morphology and MTT staining as index. The protective effects of NMDA receptor antagonist ketamine and an anti-inflammatory drug minocycline on insult induced by NMDA 50 umol/L for 3 h were observed, and the toxic effect of minocycline on normally cultured neurons was also observed. We found that NMDA concentration-dependently injured the cultured neurons. Pretreatments with ketamine 100, 10, 1 umol/L and minocycline 135, 45 umol/L protected NMDA (50 umol/L)-induced cortical neuron damage (P < 0.01), but minocycline added after NMDA treatment did not show the protective effect. Minocycline at 135, 45 umol/L for 24 h, not 3 h, showed toxic effect on neurons at DIV4, DIV7 and DIV 10 (P < 0.001), and this toxic effect was attenuated when the culture time in vitro was longer. These results indicate that cultured primary neurons in 96-well microplates can be used forhigh-efficient evaluating neuroprotective and neurotoxic effects of drugs in vitro.ConclusionsIn the first part of our experiments, we developed a new model for evaluating central depressant drugs using...
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