Watanabe S, Inoue T, Murakami M, Inokuma Y, Kawahara S, Kirino Y
Laboratory of Neurobiophysics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, 113-0033, Tokyo, Japan.
Brain Res. 2001 Mar 30;896(1-2):30-5. doi: 10.1016/s0006-8993(00)03242-x.
The neurons in the procerebrum (PC) of the terrestrial slug Limax marginatus show regular oscillation of their membrane potential, and the oscillation has been implicated in olfactory processing. The neural mechanisms for the generation and modulation of the oscillation have been poorly understood. In the present work, we examined the ionic conductances evoked by acetylcholine (ACh) in the PC neurons and the effects of ACh application on the population activities of intrinsic and extrinsic neurons. The PC neurons are categorized into bursting neurons, which are putative local inhibitory neurons, and nonbursting neurons, which likely mediate the input and output of information in the PC. Bath application of ACh augmented the local field potential oscillation in the PC. Perforated patch recording from single PC neurons revealed that ACh has direct excitatory effects on bursting neurons, while it suppresses the activity of nonbursting neurons, possibly via augmented inhibitory synaptic input from bursting neurons. The correlation between the membrane potential of bursting neurons and the frequency of oscillation suggests that bursting neurons are the main determinant of the oscillation frequency. Application of ACh also resulted in a reduction of the oscillation amplitude in the olfactory nerve, suggesting that the frequency modulation in the oscillatory network could change the activities in the follower neurons.
陆生蛞蝓边缘大蛞蝓前脑（PC）中的神经元表现出膜电位的规则振荡，并且这种振荡与嗅觉处理有关。然而，对于这种振荡的产生和调节的神经机制，人们了解甚少。在本研究中，我们研究了乙酰胆碱（ACh）在PC神经元中诱发的离子电导，以及ACh应用对内在和外在神经元群体活动的影响。PC神经元可分为爆发性神经元（推测为局部抑制性神经元）和非爆发性神经元（可能介导PC中信息的输入和输出）。在浴液中应用ACh增强了PC中的局部场电位振荡。从单个PC神经元进行穿孔膜片钳记录显示，ACh对爆发性神经元有直接兴奋作用，而它可能通过增强来自爆发性神经元的抑制性突触输入来抑制非爆发性神经元的活动。爆发性神经元的膜电位与振荡频率之间的相关性表明，爆发性神经元是振荡频率的主要决定因素。应用ACh还导致嗅神经中振荡幅度的降低，这表明振荡网络中的频率调制可能会改变跟随神经元的活动。
