Reversible inactivation of the dorsal hippocampus by tetrodotoxin or lidocaine: A comparative study on cerebral functional activity and motor coordination in the rat
Reversible inactivation of the dorsal hippocampus by tetrodotoxin or lidocaine: A comparative study on cerebral functional activity and motor coordination in the rat
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DOI：
10.1016/j.neuroscience.2006.05.023
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发表时间：
2006-01-01
期刊：
影响因子：
3.3
通讯作者：
Cassel, J. C.
中科院分区：
文献类型：
--
作者：
De Vasconcelos, A. Pereira;Klur, S.;Cassel, J. C.
用利多卡因或河豚毒素可逆地使海马区失活，以研究这种结构在记忆过程中的意义。与这种停用有关的关键点是封锁的时间和空间范围。我们比较了常用剂量的利多卡因(5或10毫克)或河豚毒素(5或10 ng)在两个延迟时间(5或30分钟)注入大鼠海马区的效果，用2-脱氧葡萄糖放射自显影显示局部大脑葡萄糖代谢，并用光束行走能力评估运动协调能力。此外，在双侧注入利多卡因10mU后，在水迷宫中评估记忆恢复。单侧河豚毒素注射可引起注射部位附近(背侧海马区：-29%至-67%)以及其他同侧和对侧脑区(腹侧海马区、外侧丘脑、皮质区)2-脱氧葡萄糖摄取量随剂量和时间的减少而减少。在注射河豚毒素和注射2-脱氧葡萄糖之间延迟30min时，10 ng的效果最好。单侧和双侧输注河豚毒素可导致严重的运动协调障碍。相反，利多卡因仅在10微克时降低了背侧海马区2-脱氧葡萄糖摄取量(-19%)，对海马区外的影响很弱。无论是单侧还是双侧输注，无论剂量如何，利多卡因都不会改变运动协调性。然而，当双侧注射利多卡因时，10毫克利多卡因会损害水迷宫中空间信息的短期提取。由于利多卡因I)引起了一种主要局限于输液部位的微弱而显著的功能阻断，II)对运动协调没有影响，然而III)改变了短期空间记忆提取，我们得出结论，在本文所用的剂量下，利多卡因急性海马内注射可能比河豚毒素具有一些优势。(C)2006年IBRO。爱思唯尔有限公司出版。保留所有权利。
Reversible inactivation of the hippocampus by lidocaine or tetrodotoxin is used to investigate implications of this structure in memory processes. Crucial points related to such inactivation are the temporal and spatial extents of the blockade. We compared effects of intrahippocampal infusions of commonly-used doses of lidocaine (5 or 10 mu g) or tetrodotoxin (5 or 10 ng) in rats at two post-infusion delays (5 or 30 min), using 2-deoxyglucose autoradiography to visualize local cerebral glucose metabolism, and beam-walking performance to assess motor coordination. In addition, memory retrieval was evaluated in a water maze after bilateral infusions of 10 mu g lidocaine. A unilateral tetrodotoxin infusion induced dose- and time-dependent reductions of 2-deoxyglucose uptake in the vicinity of the infusion site (dorsal hippocampus: -29% to -67%) and in other ipsi- and contralateral brain regions (ventral hippocampus, lateral thalamus, cortical regions). The maximal effect was at 10 ng, at the delay of 30 min between the tetrodotoxin infusion and the 2-deoxyglucose injection. Uni- and bilateral infusions of tetrodotoxin induced dramatic motor coordination deficits. Conversely, lidocaine reduced 2-deoxyglucose uptake (-19%) in the dorsal hippocampus only at 10 mu g, with weak extrahippocampal effects. Whether infused uni- or bilaterally and regardless of the dose, lidocaine did not alter motor coordination. When infused bilaterally, however, 10 mu g of lidocaine impaired short-term retrieval of spatial information in a water maze. Because lidocaine i) induced a weak though significant functional blockade mainly restricted to the infusion site, ii) had no consequences on motor coordination and, nevertheless iii) altered short-term spatial memory retrieval, we conclude that acute intrahippocampal infusions of lidocaine may offer some advantages over tetrodotoxin at the doses used herein. (c) 2006 IBRO. Published by Elsevier Ltd. All rights reserved.