Gołebiewski H, Eckersdorf B, Konopacki J
Department of Neurobiology, University of Lódź, Poland.
Acta Neurobiol Exp (Wars). 1996;56(1):147-53. doi: 10.55782/ane-1996-1114.
The generation of EEG theta rhythm (RSA) in the hippocampal formation is a prime example of rhythmic activity involving central mechanisms of oscillation and synchrony. Cholinergic nature of the in vitro and in vivo induced RSA has been undoubtedly established. Recently, we have demonstrated in vitro that the hippocampal formation theta rhythm resulted from interaction between the cholinergic and GABAergic systems. In the present study we have provided additional in vitro evidence that the hippocampal GABA-A receptors are actively involved in the mechanism of theta production. Specifically, we demonstrated that bicuculline-GABA-A antagonist significantly augmented carbachol induced theta response increasing amplitude and power of rhythmical slow waves. In separate experiments the carbachol+bicuculline induced RSA were studied in the presence of muscarinic M1 and M2 antagonists--pirenzepine and gallamine (respectively) and GABA-A agonist--muscimol. Both pirenzepine and muscimol antagonized induced theta oscillations and gallamine was found to be completely ineffective in blocking this EEG response. The results provided evidence for M1 cholinergic/GABA-Aergic interaction in mechanisms responsible for theta production.
海马结构中脑电θ节律（RSA）的产生是涉及振荡和同步中枢机制的节律性活动的一个主要例子。体外和体内诱导的RSA的胆碱能性质已得到明确证实。最近，我们在体外证明，海马结构的θ节律是由胆碱能系统和GABA能系统之间的相互作用产生的。在本研究中，我们提供了额外的体外证据，表明海马GABA-A受体积极参与θ产生机制。具体而言，我们证明荷包牡丹碱（一种GABA-A拮抗剂）显著增强了卡巴胆碱诱导的θ反应，增加了节律性慢波的振幅和功率。在单独的实验中，在毒蕈碱M1和M2拮抗剂（分别为哌仑西平和加拉明）以及GABA-A激动剂蝇蕈醇存在的情况下，研究了卡巴胆碱+荷包牡丹碱诱导的RSA。哌仑西平和蝇蕈醇均拮抗诱导的θ振荡，而加拉明被发现对阻断这种脑电反应完全无效。这些结果为负责θ产生的机制中M1胆碱能/GABA-A能相互作用提供了证据。
