Voltage clamp principle and operation
The design principle is that the transmembrane ion current (I) is formed when the ion moves across the membrane. The permeability is the degree of resistance of the ion passing through the membrane, and the reciprocal of the membrane resistance (R), that is, the membrane conductance (G). As a result, the membrane resistance becomes smaller when the membrane permeability increases, i.e., the conductance of the membrane to the ion increases. According to Ohm's law V=IR, namely I=V/R=VG, so, as long as the fixed on both sides of the membrane potential difference (V), transmembrane current measured (I) changes, can be used as a measure of membrane conductance changes, changes of membrane permeability can be understood.
Na+ channel blocker, tetrodotoxin (TTX), K+ channel blocker four and ethylamine (TEA) were applied to the cell membrane respectively.Compared with the control group, the Na+ channel was blocked by TTX treatment and the remaining K+ channels were above zero potential;The K+ channel was blocked by TEA treatment and the remaining Na+ channels were below zero.
The voltage clamp device has two microelectrode into the cell, is a measurement of the membrane potential of Em microelectrode, it through a high impedance preamplifier (XI) detection of membrane potential (Em), and the signal input feedback amplifier (FBA); the other electrode I and FBA connected to the output end, as the injection current to the cell in a receiving potential Em input two input FBA, another received command potential (C), when the potential is equal to the output current is zero, when the difference between the two, the FBA electrode I output current injection into cells, the current potential changes tend to command potential C in the film two side, so as to form a feedback circuit so that the membrane potential is always equal to the command potential of C, the change of recorded Im can reflect the membrane conductance of G. In fact, the Im is the current injected through the electrode I, which is exactly opposite the channel current during the voltage clamp and keeps the film current constant.
You are talking about high voltage clamps, mainly insulated and insulated. When using the voltage level depends on the correct use, generally used in live for high-voltage fuse what
