Intracellular Recordings

细胞内记录是一种电生理技术，它将玻璃微电极插入单个细胞（通常是神经元）中，以精确测量其电活性（跨细胞膜的电压或电流）。它可以允许记录较慢的分级电压（受体电位或突触电位），这对于涉及神经信号传导的研究至关重要。

Signal Overview

There are several variations of intracellular techniques, which can be grouped by the type of glass microelectrode used. The first group uses a microelectrode with a relatively small tip (fine or sharp), while the second uses a relatively large tip (blunt or patch). Each technique uses Ohm’s Law to focus on various aspects of the electrical activity.

锋利的电极
膜电位/电压（电流夹紧）：This technique measures the membrane potential by injecting a constant electrical current through the recording electrode, which is usually done to probe the passive or active properties of the cell membrane. The amplifier involved is designed to compensate for any resistive artifacts by the microelectrode. Current injection can also be used to introduce charged substances into the cell (iontophoresis), which can be used in cell marking techniques.

膜电流（电压夹紧）：经典电压夹具涉及使用两个电极（两个电极电压夹具或TEVC），其中一个电极记录细胞内电压和另一电极注入电流。电压钳放大器在记录的电压和注入电流之间形成反馈电路。然后，这允许将电池膜电压更改为各种保持值，同时记录实现相应的“夹紧”电压所需的相关注入电流。TEVC最常用于大细胞（例如卵母细胞），因此有时被称为卵母细胞夹紧。另一个电压夹具技术是单电极电压夹具（SEVC），有时称为开关夹具，使用了一种时间共享技术，该技术在记录电压和将电流注入单个细胞内电极之间交替。它使用高频数字开关电路，其中录制时间短而速度足够快，可以保持“夹紧”。

Patch Clamping
与传统那锋利的电极技术t involves impaling a cell, the patch microelectrode is placed next to a cell, and gentle suction is applied to draw a piece of the cell membrane (known as the 'patch') into the microelectrode tip, creating a high resistance (gigaohm) seal with the cell membrane. Variations on the suction can provide a variety of patching techniques including cell-attached, whole cell (similar to sharp electrode), outside-out patch and inside-out patch. Depending on the patching techniques, currents passing through individual ion channels, or through the whole cell can be recorded, or pharmacologically analysing the patch’s membrane properties.