Fellous J M, Sejnowski T J
Computational Neurobiology Laboratory, Howard Hughes Medical Institute, Salk Institute for Biological Studies, La Jolla, California 92037, USA.
Hippocampus. 2000;10(2):187-97. doi: 10.1002/(SICI)1098-1063(2000)10:2<187::AID-HIPO8>3.0.CO;2-M.
Carbachol, a muscarinic receptor agonist, produced three distinct spontaneous oscillations in the CA3 region of rat hippocampal slices. Carbachol concentrations in the 4-13 microM range produced regular synchronized CA3 discharges at 0.5-2 Hz (carbachol-delta). Higher concentrations (13-60 microM) produced short episodes of 5-10 Hz (carbachol-theta) oscillations separated by nonsynchronous activity. Concentrations of carbachol ranging from 8-25 microM also produced irregular episodes of high-frequency discharges (carbachol-gamma, 35-70 Hz), in isolation or mixed with carbachol-theta and carbachol-delta. At carbachol concentrations sufficient to induce carbachol-theta, low concentrations of APV reversibly transformed carbachol-theta into carbachol-delta. Higher concentrations of D,L-2-amino-5-phosphonopentanoic acid (APV) reversibly and completely blocked carbachol-theta. A systematic study of the effects of carbachol shows that the frequency of spontaneous oscillations depended nonlinearly on the level of muscarinic activation. Field and intracellular recordings from CA1 and CA3 pyramidal cells and interneurons during carbachol-induced rhythms revealed that the hippocampal circuitry preserved in the slice was capable of spontaneous activity over the range of frequencies observed in vivo and suggests that the presence of these rhythms could be under neuromodulatory control.
卡巴胆碱作为一种毒蕈碱受体激动剂，在大鼠海马切片的CA3区域产生了三种不同的自发振荡。4 - 13微摩尔范围内的卡巴胆碱浓度产生0.5 - 2赫兹的规则同步CA3放电（卡巴胆碱 - δ）。更高浓度（13 - 60微摩尔）产生5 - 10赫兹的短阵振荡（卡巴胆碱 - θ），其间夹杂非同步活动。8 - 25微摩尔范围内的卡巴胆碱浓度还会产生孤立的或与卡巴胆碱 - θ和卡巴胆碱 - δ混合的高频放电不规则阵发（卡巴胆碱 - γ，35 - 70赫兹）。在足以诱导卡巴胆碱 - θ的卡巴胆碱浓度下，低浓度的APV可将卡巴胆碱 - θ可逆地转变为卡巴胆碱 - δ。更高浓度的D,L - 2 - 氨基 - 5 - 膦酰基戊酸（APV）可可逆且完全地阻断卡巴胆碱 - θ。对卡巴胆碱作用的系统研究表明，自发振荡的频率非线性地依赖于毒蕈碱激活水平。在卡巴胆碱诱导的节律期间，对CA1和CA3锥体细胞及中间神经元进行的场电位和细胞内记录显示，切片中保留的海马环路能够在体内观察到的频率范围内自发活动，这表明这些节律的存在可能受神经调节控制。
