Patch Clamp technique Flashcards
How does an amplifier work in a circuit?
Uses electrical power to increase the amplitude of an incoming signal voltage or current signal
High impedance
means that a point in a circuit (a node) allows a relatively small amount of current through, per unit of applied voltage at that point. High impedance circuits are low current and potentially high voltage
Patch clamp technique
Developed to study behaviour of single ion channels
amplifier + resistor + voltage
Can also be used for synaptic transmission recordings
Why is high seal resistance important?
To reduce noise in the recording to allow resolution of single channel openings
Gigaseal
glass pipette with a resistance of >1 gigaohm (GΩ)
how do you know you’ve found a single ion channel?
more closures than openings
same activity (no superposition)entire time after long time at permissive voltage
follows HH kinetics
what does lower capicitance mean when recording?
less noise
cell attach configuration
record intact membrane w channel under pipette
not much control e.g. conc of ligands in cell
high resolution i.e. good signal:noise
Inside out recording
Suction to invert piece of membrane and expose intracellular face to controlled concentratikn
Observe modulation from inside
Whole cell recording
Suction to break membrane
Observe complete flux in entire cell
Very noisy
Outside-out recording
Membrane snaps when pipette is retracted and fuses together in pipette
Extracellular domain outside
Observe ligand fated reactions w high resolution
Conc can be controlled
Piezo device
Piezoelectrcity is the electric charge that accumulates in certain solid materials—such as crystals, certain ceramics, and biological matter such as bone, DNA, and various proteins—in response to applied mechanical stress.
Used w patchclamp so it can be highly controlled
Theta tubing w agonist on one side and control on other
Glutamate receptor recording
Rapid rise(openings) and slow decay as agonist slowly unbinds
6 channels
GABA = 5 channels
