Popova I Yu, Karavaev E N, Kitchigina V F
Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushshino, Russia.
Zh Vyssh Nerv Deiat Im I P Pavlova. 2011 Nov-Dec;61(6):724-35.
Inter-neuronal interactions within the medial septum/diagonal band complex (MSDB) are of great interest as this region is believed to be the hippocampal theta rhythm pacemaker. However, the role of glutamatergic system in functioning of the septal cells is yet unclear. Here, we demonstrate for the first time the effects of glutamate in physiological concentration (1 microM) on the MSDB neuronal spontaneous and evoked activities in vitro. These effects (activation of 70% and inhibition of 30% of responsive neurons) differed in pacemaker and non-pacemaker cells. Pacemaker cells were always activated under glutamate, whereas non-pacemaker neurons could be either activated or inhibited. Indeed, in the burst pacemakers, glutamate increased the frequency of rhythmic activity. In a total MSDB neuron population, in 30% of neurons glutamate applications modified responses to the electrical stimulation by unifying the temporal parameters of neuron responses. Along with the increase in the theta-burst frequency, this indicates that the glutamatergic system is involved in the process ofintraseptal synchronization. Obtained data shed light on the role ofglutamatergic system in septal neuron interactions and broaden our understanding of theta oscillation mechanisms in the septo-hippocampal system.
内侧隔区/斜角带复合体（MSDB）内的神经元间相互作用备受关注，因为该区域被认为是海马θ节律起搏器。然而，谷氨酸能系统在隔区细胞功能中的作用尚不清楚。在此，我们首次证明了生理浓度（1微摩尔）的谷氨酸对体外MSDB神经元自发活动和诱发活动的影响。这些影响（70%的反应性神经元被激活，30%被抑制）在起搏器细胞和非起搏器细胞中有所不同。起搏器细胞在谷氨酸作用下总是被激活，而非起搏器神经元可能被激活或抑制。事实上，在爆发性起搏器中，谷氨酸增加了节律性活动的频率。在整个MSDB神经元群体中，30%的神经元在应用谷氨酸后，通过统一神经元反应的时间参数，改变了对电刺激的反应。随着θ爆发频率的增加，这表明谷氨酸能系统参与了隔区内同步化过程。所获得的数据揭示了谷氨酸能系统在隔区神经元相互作用中的作用，并拓宽了我们对隔-海马系统中θ振荡机制的理解。
