Olfactory bulb networks revealed by lateral olfactory tract stimulation in the in vitro isolated guinea-pig brain.
Olfactory bulb networks revealed by lateral olfactory tract stimulation in the in vitro isolated guinea-pig brain.
复制标题
体外分离的豚鼠大脑中通过侧嗅束刺激揭示的嗅球网络。
DOI：
10.1016/j.neuroscience.2006.06.047
复制
发表时间：
2006
期刊：
影响因子：
3.3
通讯作者：
deCurtis,M
中科院分区：
文献类型：
--
作者：
Uva,L;Strowbridge,BW;deCurtis,M
嗅觉信息的加工是通过嗅球和梨状边缘皮质之间的突触联系来实现的。使用普通的体内和体外准备的有限的可及性阻碍了先前对这些突触相互作用的定义。我们利用分离的豚鼠脑制剂来克服这些实验限制。先前的研究表明，该制剂在体外通过动脉灌流维持广泛的功能保存。在刺激外侧嗅束(LOT)和梨状皮质前部(APC)后，用多通道探头测量OB的场电位层。电流源密度分析被用来重建与固有突触活动相关的电流汇/源。Lot刺激依次诱导1)位于二尖瓣细胞层的反向群峰电位(2.66±0.39ms)，其对100 Hz高频刺激(HFS)和6-氰基-7-硝基-2，3-二酮(CNQX)(10μM)具有抵抗力；II)位于外丛状层的成分(3.85±0.63ms)不受HFS的影响；III)在外丛状层产生的大幅度电位(峰值为5.84±0.58ms)，可被HFS和CNQX消除，但不被荷包牡丹碱(50μM)所消除，(4)延迟反应(起效时间20.00±2.94ms)被CNQX消除，并被荷包牡丹碱增强。刺激APC还可产生被HFS和CNQX消除的晚电位。APC诱发的反应和晚期Lot诱发的反应都被横切取消，以将OB与APC分开。这些结果表明，在一个孤立的哺乳动物大脑标本中，在OB和梨状皮质结构之间存在相互突触相互作用。
Olfactory information processing is mediated by synaptic connections between the olfactory bulbs (OBs) and piriform–limbic cortices. Limited accessibility using common in vivo and in vitro preparations has hindered previous attempts to define these synaptic interactions. We utilized the isolated guinea-pig brain preparation to overcome these experimental limitations. Previous studies demonstrated extensive functional preservation in this preparation maintained in vitro by arterial perfusion. Field potential laminar profiles were performed with multi-channel probes in the OB following stimulation of both the lateral olfactory tract (LOT) and the anterior piriform cortex (APC). Current-source density analysis was carried out on laminar profiles to reconstruct current sinks/sources associated with intrinsic synaptic activities. LOT stimulation induced sequentially i) an antidromic population spike (at 2.66±0.39 ms) located in the mitral cell layer that was resistant to 100 Hz high-frequency stimulation (HFS) and 6-cyano-7-nitroquinoxaline-2,3-dione (CNQX) (10 μM), ii) a component located in the external plexiform layer at 3.85±0.63 ms that was unaffected by HFS, iii) a large amplitude potential (peak amplitude at 5.84±0.58 ms) generated in the external plexiform layer, abolished by HFS and CNQX, but not by bicuculline (50 μM), iv) a late response (onset at 20.00±2.94 ms) abolished by CNQX and enhanced by bicuculline. Stimulation of the APC also induced a late potential abolished by HFS and CNQX. Both APC-evoked and late LOT-evoked responses were abolished by a transverse cut to separate OB from APC. These results demonstrate in an isolated mammalian brain preparation the presence of reciprocal synaptic interactions between the OB and piriform cortical structures.