Axonal bleb recording

Abstract

Patch-clamp recording requires direct accessibility of the cell membrane to patch pipettes and allows the investigation of ion channel properties and functions in specific cellular compartments. The cell body and relatively thick dendrites are the most accessible compartments of a neuron, due to their large diameters and therefore great membrane surface areas. However, axons are normally inaccessible to patch pipettes because of their thin structure; thus studies of axon physiology have long been hampered by the lack of axon recording methods. Recently, a new method of patchclamp recording has been developed, enabling direct and tight-seal recording from cortical axons. These recordings are performed at the enlarged structure (axonal bleb) formed at the cut end of an axon after slicing procedures. This method has facilitated studies of the mechanisms underlying the generation and propagation of the main output signal, the action potential, and led to the finding that cortical neurons communicate not only in action potential-mediated digital mode but also in membrane potential-dependent analog mode.

Hippocampal “cholinergic interneurons” visualized with the choline acetyltransferase promoter: anatomical distribution, intrinsic membrane properties, neurochemical characteristics, and capacity for cholinergic modulation

“…These ChAT-tauGFP structures tended to be found in CA1 and CA3 stratum oriens, which may be a reflection of the density of MS-DBB cholinergic afferents in HC layers. Axon blebs, which can approach the size of ChAT-tauGFP globular structures measured here, are observed only after the axon is severed (Shu et al, 2006 ; Hu and Shu, 2012 ). However, the ChAT-tauGFP axon appears to be intact (Figure 1K , inset), resembling large, en passant boutons.…”

Differential roles of NaV1.2 and NaV1.6 in regulating neuronal excitability at febrile temperature and distinct contributions to febrile seizures

“…Coronal slices from prefrontal cortex with a thickness of 300 μm were prepared as described previously 40 . We made somatic nucleated patch recordings for currents derived from Na V 1.2 channels and isolated axonal blebs recordings for currents mainly mediated by Na V 1.6 40 , 70 .…”

Regulation of Action Potential Waveforms by Axonal GABAA Receptors in Cortical Pyramidal Neurons

“…Isolated axon blebs could be obtained by sweeping a sharp electrode at the border between layer –6and the white matter [20]. We then recorded axonal blebs in the white-matter side.…”