PHIL 2015 Chapter Notes - Chapter 7.9: Voltage Clamp, Patch Clamp, Current Clamp
23 May 2020
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Document Summary
The rapid changing of ion permeability is achieved through the gating of ion channels. In an action potential or synaptic events, hundreds or thousands of individual channels can open to regulate overall membrane conductance. The summed activity of all these channels creates a smooth change in membrane potential. Each individual channel is binary: conducting or non-conducting. Permeability is determined by the probability that the channels are open. Binding of a ligand to a ligand binding domain causes a conformational change that opens a pore and allows ions to flow. Highly charged voltage- senseitive regions which move in response to changes in membrane potential. We can use glass micro-pipettes to isolate and study single ion channels in the membrane. A tight seal (giga-ohm) between the membrane and glass pipette means thatelectrical activity through the channel can be measured without noise . Patch of membrane is clamped at a single voltage.
