Nicotine induction of theta frequency oscillations in rodent medial septal diagonal band in vitro  

作　　者：Cheng-biao LU Cheng-zhang LI Dong-liang LI Zaineb HENDERSON 

机构地区：[1]Department of Physiology and Neurobiology, Xinxiang Medical University, Xinxiang 453003, China [2]Institute of Membrane and Sys- tems Biology, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK

出　　处：《Acta Pharmacologica Sinica》2013年第6期819-829,共11页中国药理学报（英文版）

基　　金：This work was supported by National Natural Science Foundation of China （grant No 31070938, No 81271422） and the UK Medical Research Council （grant No G0500823 ）.

摘　　要：Aim. This study aimed to examine the role of the nicotinic receptor （nAChR） in the generation of theta oscillations （4-12 Hz） in vitro. Methods： Electrophysiological studies were performed on medial septal diagonal band area （MSDB） slices to measure theta oscillation Immunofluorescence and confocal microscopy studies were carried out to detect α4 nAChR and 132 nAChR subunits in perfused-fixed tissue from VGluT2-GFP and GAD67-GFP transgenic mice. Results： Application of nicotine to MSDB slices produced persistent theta oscillations in which area power increased in a dose- responsive manner. This activity was inhibited by GABAA receptor antagonists and partially by ionotropic glutamate receptor antagonists, indicating the involvement of local GABAergic and glutamatergic neurons in the production of the rhythmic activity. The nicotine- induced theta activity was also inhibited selectively by non-α7＊nAChR antagonists, suggesting the presence of these receptor types on GABAergic and glutamatergic neuron populations in the MSDB, This was confirmed by immunofluorescence and confocal microscopy studies in transgenic mice in which the GABAergic and glutamatergic neurons express green fluorescent protein （GFP）, showing Iocalisation of β2 nAChR and a4 nAChR subunits, the most common constituents of non-α7＊nAChRs, in both cell types in the MSDB. Conclusion： Theta activity in the MSDB may be generated by tonic stimulation of non-α7＊nAChRs.Aim. This study aimed to examine the role of the nicotinic receptor （nAChR） in the generation of theta oscillations （4-12 Hz） in vitro. Methods： Electrophysiological studies were performed on medial septal diagonal band area （MSDB） slices to measure theta oscillation Immunofluorescence and confocal microscopy studies were carried out to detect α4 nAChR and 132 nAChR subunits in perfused-fixed tissue from VGluT2-GFP and GAD67-GFP transgenic mice. Results： Application of nicotine to MSDB slices produced persistent theta oscillations in which area power increased in a dose- responsive manner. This activity was inhibited by GABAA receptor antagonists and partially by ionotropic glutamate receptor antagonists, indicating the involvement of local GABAergic and glutamatergic neurons in the production of the rhythmic activity. The nicotine- induced theta activity was also inhibited selectively by non-α7＊nAChR antagonists, suggesting the presence of these receptor types on GABAergic and glutamatergic neuron populations in the MSDB, This was confirmed by immunofluorescence and confocal microscopy studies in transgenic mice in which the GABAergic and glutamatergic neurons express green fluorescent protein （GFP）, showing Iocalisation of β2 nAChR and a4 nAChR subunits, the most common constituents of non-α7＊nAChRs, in both cell types in the MSDB. Conclusion： Theta activity in the MSDB may be generated by tonic stimulation of non-α7＊nAChRs.

关 键 词：nicotinic receptors medial septal diagonal band RHYTHMOGENESIS hippocampal theta rhythm learning and memory Alzheimer＇s disease 

分 类 号：Q813[生物学—生物工程] TM712[电气工程—电力系统及自动化]