Endocannabinoid regulates the efficacy of vestibular inhibitory synapses contributing to the expression of gravity-detection behavior in developing rats
作者单位：Departments of PhysiologyLi Ka Shing Faculty of MedicineThe University of Hong Kong Departments of BiochemistryLi Ka Shing Faculty of MedicineThe University of Hong Kong
会议名称：《中国神经科学学会第十届全国学术会议》
会议日期：2013年
学科分类：1001[医学-基础医学(可授医学、理学学位)] 10[医学]
关 键 词：endocannabinoid Long-term depression gravity-detection behavior
摘 要：Long-term depression of inhibitory responses(iLTD),as mediated by endocannabinoid(eCB),plays an important role on presynaptic plasticity in the mammalian ***,the involvement of eCB on the developmental plasticity of the vestibular system remains *** hypothesize that eCB regulates the efficacy of GABAergic synapses in the vestibular nucleus(VN) via the modulation of iLTD,thereby contributing to spatial *** the use of whole-cell patch-clamp experiments,GABA receptor-mediated evoked-IPSCs were recorded on brainstem slice of postnatal *** normal P5-7 rats,iLTD was induced in 70%of the neurons in the medial VN but was reduced to 20%in P8-17 *** proportion of neurons showing iLTD at P5-7 decreased to 40%with bath application of AM251(antagonist of CB1 receptor).Similar results were observed in P5-7 rats pre-implanted at P1 with AM251-loaded Elvax slice that allows slow release of the drug into the underlying *** normal P8-10 rats,the proportion of neurons showing iLTD increased to 60%with bath application of WIN55(agonist of CB1R).Similar results were observed in P8-10 rats pre-implanted at P1 with WIN55-loaded Elvax ***,the proportion decreased to 20%in P11-17 rats pretreated with *** determine the receptor that triggers postsynaptic production and release of eCB we applied to the bath antagonist/agonist of either Group Ⅰmetabotropic glutamate receptor(mGluR) or serotonin receptor(5-HTR).Antagonist/agonist of Group Ⅰ mGluR exerted no effect on iLTD ***,5-HTR agonist increased the proportion of neurons expressing iLTD in P8-10 rats while 5-HTR antagonist decreased the proportion in P5-7 rats,suggesting that 5-HTR is involved in triggering eCB *** investigate the effects of eCB in the expression of vestibular behavior,rats pre-implanted at P1 with AM251- or WIN55-loaded Elvax were tested with negative geotaxis,a behavioral indicator of *** rats acquire the re-orienting beha