Influence of activities in arousal system on the excitability of principal neurons of entorhinal cortex and memory
会议名称：《中国神经科学学会第九届全国学术会议暨第五次会员代表大会》
会议日期：2011年
学科分类：0710[理学-生物学] 07[理学] 071006[理学-神经生物学]
基 金：supported by NSFC(No81055678)
关 键 词：orexin entorhinal cortex learning and memory
摘 要：The entorhinal cortex(EC) has long been regarded as a bidirectional gateway between higher cortical areas and the hippocampus.Orexins(hypocretins) are wake-promoting neuropeptides which are mainly produced by the neurons within the lateral hypothalamus.Orexin system includes two separate peptides orexin-A and orexin-B proteolytically derived from the same precursor protein and two specific G-protein-coupled receptors OX1R and OX2R.In the present study,we firstly investigated the electrophysiological effects of orexin-A on stellate neurons and pyramidal neurons in live brain slices of the EC using whole-cell patch-clamp recordings,and then observed signaling cascades triggering the ionic and synaptic mechanisms involved in orexin-A.The results show as follow:Orexin-A depolarizes stellate and pyramidal neurons in the superficial layers of EC throμgh effects on K channels and nonselective cation conductances.The excitatory action of orexin-A involves OX1Rs and PKC mediates both the inhibition of IK and activation of NSCC induced by orexin-A.Orexin-A enhances both excitatory and inhibitory synaptic transmissions in the superficial layers of EC via OX1Rs.In summury,the studies reported here provide evidence that the direct excitatory effects of orexin-A on principal neurons in the superficial layers of rat EC are mediated by the activation of OX1Rs and PKC signaling cascades,which inhibit sustained K current and activate NSCC.In addition, orexin-A enhances both excitatory and inhibitory synaptic transmissions in the EC via OX1Rs.