海马内生长抑素与γ－氨基丁酸在大鼠穿梭箱主动回避反应中的作用

EFFECTS OF SOMATOSTATIN AND GABA IN HIPPOCAMPUS ON THE ACTIVE AVOIDANCE RESPONSE IN RATS

本实验以大鼠穿梭箱主动回避反应（ＡＡＲ）的习得和消退为学习记忆的指标，研究了海马内生长抑素（ＳＳ）和γ－氨基丁酸（ＧＡＢＡ）在学习记忆中的作用。结果如下：（１）经训练而建立了ＡＡＲ的大鼠，其海马内ＳＳ较对照组显著增高，而海马内ＧＡＢＡ含量却明显降低；（２）海马内注入ＳＳ的耗竭剂半胱胺（Ｃｙｓ，２０ｇ／Ｌ）使大鼠ＡＡＲ的习得受到明显损害，ＡＡＲ的消退显著加速，海马内ＳＳ明显降低，而ＧＡＢＡ含量却显著升高；（３）海马内注入ＧＡＢＡ（２００ｇ／Ｌ）使大鼠ＡＡＲ的消退显著加速的同时，其海马内ＳＳ含量亦显著降低。由此表明，海马内ＳＳ可能有促进学习记忆的作用，而海马内ＧＡＢＡ升高则有相反的效应；二者在海马调控学习记忆过程中具有重要作用。

The effects of somatostatin(SS)and GABA in hippocampus on learning and memory werestudied with the active avoidance response(AAR)in shuttle-box as the index of learning andmemory.The results were as follows:(1)The SS content in the hippocampus of the rats acquiredAAR markedly increased(P<001),while the GABA content in their hippocampus significantlydecreased;(2)After intrahippocampal injection of (ih)cysteamine (Cys,20g/L),a SS-depletingagent, the acquisition of AAR markedly attenuated(P<0.01 )and the extinction of AARsignificantly quickened(P< 0.01).Meanwhile the SS content decreased by 40% and the GABAcontent significantly increased(P<0.01) in hippocampus;(3) GABA(200g/L,ih)obviouslyquickened the extinction of AAR and reduced the hippocampal SS content.The results suggestthat the SS in hippocampus facilitate learning and memory, while the increase in GABA contentof hippocampus may have the opposed effect.Both SS and GABA in hippocampus may play animportant role in the regulation of learning and memory.