Hatch Robert J, Mendis G Dulini C, Kaila Kai, Reid Christopher A, Petrou Steven
The Florey Institute of Neuroscience and Mental Health, The University of MelbourneMelbourne, VIC, Australia.
Department of Mechanical Engineering, The University of MelbourneMelbourne, VIC, Australia.
Front Cell Neurosci. 2017 Jul 17;11:204. doi: 10.3389/fncel.2017.00204. eCollection 2017.
Gap junctions form electrical synapses that modulate neuronal activity by synchronizing action potential (AP) firing of cortical interneurons (INs). Gap junctions are thought to form predominantly within cortical INs of the same functional class and are therefore considered to act within discrete neuronal populations. Here, we challenge that view and show that the probability of electrical coupling is the same within and between regular-spiking (RS) and fast-spiking (FS) cortical INs in 16-21 days old mice. Firing properties of these two populations were distinct from other INs types including neurogliaform and low-threshold spiking (LTS) cells. We also demonstrate that pre-junctional APs can depolarize post-junctional neurons and increase the probability of firing. Our findings of frequent gap junction coupling between functionally distinct IN subtypes suggest that cortical IN networks are much more extensive and heterogeneous than previously thought. This may have implications on mechanisms ranging from cognitive functions to modulation of pathological states in epilepsy and other neurological disorders.
缝隙连接形成电突触，通过同步皮层中间神经元（INs）的动作电位（AP）发放来调节神经元活动。缝隙连接被认为主要在相同功能类别的皮层中间神经元内形成，因此被认为在离散的神经元群体中起作用。在这里，我们对这一观点提出质疑，并表明在16 - 21日龄小鼠的规则发放（RS）和快速发放（FS）皮层中间神经元内部以及它们之间，电耦合的概率是相同的。这两种群体的发放特性与其他中间神经元类型不同，包括神经胶质样细胞和低阈值发放（LTS）细胞。我们还证明，突触前动作电位可以使突触后神经元去极化并增加发放概率。我们关于功能不同的中间神经元亚型之间频繁缝隙连接耦合的发现表明，皮层中间神经元网络比以前认为的要广泛得多且更加异质。这可能对从认知功能到癫痫和其他神经系统疾病病理状态调节等一系列机制产生影响。
