Synthetic Cannabinoid Hu210 On Spatial Reference Memory Effects

Moraceae plant cannabis (marijuna) is a kind of addictive plants to be known by human earliest, because of its unique pharmacological effect, researchers have paid attention to it for a long time. Currently, cannabinoid is mainly used to some diseases which can not be cured by other drugs, such as applying cannabinoids to the nervous system diseases:pain, brain injury, stroke, multiple sclerosis, Parkinson's disease, Alzheimer's disease, Huntington's disease, epilepsy, amyotrophic lateral sclerosis, sleep disorders and so on. In addition, cannabinoids can also be used for cardiovascular disease, glaucoma, asthma, antiemetic, appetite. However, the use of cannabinoids as medicine is also encountered some problems, such as the psychological effects of cannabis on the central nervous system; the great effect of cannabinoids on learning and memory, emotion of the user. For the complexity of effect and mechanism of the cannabinoids, the different nations have debated on its legalization of medical use for a long time.In order to make better use of cannabinoids, and provide some theoretical evidences for the legislation on medical use of it, through the Morris water maze test, our study research the effect of synthetic cannabinoid HU210 on spatial learning and memory in rats and discuss the effect of dose, the duration of HU210 treatment, the time point of HU210 administration, and the LTD-blocking peptide. The results are as followings:1 The effect of HU210 on spatial learning and memory is dose-dependent.In the training phase of Morris water maze test, rats receive intraperitoneal injection of HU210 per day in consecutive 5 days. HU210 can affect the acquisition of spatial learning and memory and the performance during the probe test which is dose-dependent. In the dose range of 0μg/kg-100μg/kg. the impact of HU210 on spatial learning and memory is gradually increasing as the dose increases.Administration of lower dose HU210. as 25μg/kg.5μg/kg. its effect on spatial learning and memory may also drop down. Enhancing the difficulty of the study task, low doses of HU210 may have a positive impact on spatial learning and memory, leading a better performance in water maze task than control. In addition, chronic administration of low doses of HU210 may eliminate the effects of acute administration of HU210 on spatial learning and memory. 2 Priming or prolong the administration of HU210 is benefit for researching the effects of HU210 on spatial learning and memoryAccording to the investigation of the change of animals'weight, the injection of HU210 induced rapid weight loss. Suggest that we can give rats a few days priming (at least 2 days) to eliminate the physical discomfort, which may be helpful to their spatial learning and memory.In the study of escape latency we also found that the performance is no significant difference between HU210 (50μg/kg) group and control from the third day in the training test. These suggest that the increasing difficulty in task or prolonging the administration of HU210 is benefit for the spatial learning and memory, the performance of HU210 group may be better than control.3 The different time points of HU210 treatment could induce different effects on spatial learning and memoryOur study found that HU210 treatment in training test can affect the acquisition of spatial learning and memory in rats. Because the information is not well encoded in the training phase, the performance in probe test is also affected. The administration of HU210 after the test of the 5th training day could affect the consolidation of spatial learning and memory and the retrieval which lead to less accurate location and direction of the platform. The treatment of HU21030 min before the probe test could interfere the retrieval of spatial learning and memory partly which lead to less accurate location and few effects on the direction of the target.4 LTD-blocking peptide does not interfere with the effects of HU210 on spatial learning and memoryLTD-blocking peptide can block the HU210-induced LTD in vivo, but it could not play a role in behavior study. Specifically, the LTD-blocking peptide can not interfere with the effects of HU210 on the acquisition, consolidation, retrieval of spatial learning and memory.Conclusion:The mechanism of the effects of the synthetic cannabinoid HU210 on spatial learning and memory is very complex, so its effects will be interfered by various factors, such as dose, the duration of HU210 treatment, the time point of HU210 administration. So we must pay attention to the complex relationship between these factors when cannabinoids is used as medicine and the mechanism of cannabinoid should also be researched more comprehensively and more deeply.