Electrophysiology Flashcards
Volts generated by animals, such as electric eels or electric rays
700 volts
Volts in negative resting membrane potential
about -70 millivolts
Small variable changes in the membrane potential which are in the range of one to 40 millivolts.
Post-synaptic potentials
How are action potentials?
They are large, fast, and occur in an all-or-none fashion.
They reach 100 millivolts.
At rest, sodium-potassium exchanges use _____to alter the distribution of the ions across the membrane.
ATP
What similarity does electroplaques and neurons have?
They both have sodium-potassium exchanges in their plasma membrane
Volts in resting membrane potential
-60 and -80 millivolts inside the neuron
Which ions are inside the cell?
Chloride and sodium
Which neurotransmitter evoke electric discharge in electroplaques?
Acetylcholine
Number of sodium and potassium molecules exchanged in the Na+/K- ATPase
3 Na+ exit the cell and 2 K- enter the cell
Number of chloride and potassium molecules exchanged in the potassium chloride cotransporter
1 Cl- and 1 K- exit the cell
In Vmrest, which ions enter the cell by electrical gradient?
Ca+, K+ and Na+
In Vmrest, which ions enter the cell by concentration gradient?
Ca+, Cl- and Na+
In Vmrest, which ions exit the cell by electrical gradient?
Cl-
In Vmrest, which ions exit the cell by concentration gradient?
K+
Potentials generated by activation of ion channels that depolarize neurons
Excitatory postsynaptic potentials EPSP
Potentials generated by activation of ion channels that hyperpolarise neurons
Inhibitory postsynaptic potentials IPSP
Characteristics of EPSP and IPSP
Graded in amplitud due to concentration of neurotransmitter and length of the time the neurotransmitter is in the synaptic cleft
Additive but decay in amplitud as they move around the neuron
Name state of Na channels in each stage of the curve of the action potential stages
Resting Vm. Closed resting
Upstroke. Open
Peak. Closed inactivating
Downstroke. Closed inactivated
Resting Vm Close resting
Name state of Na channels in each stage of the curve of the action potential stages
Resting Vm. Closed resting
Upstroke. Closed resting
Peak. Start opening
Downstroke. Open
Resting Vm Close resting
Which types of potentials can be recorded from outside the cell?
Excitatory potentials and action potentials
Which type of potentials can be generated by neurotransmitter ion channel receptors ?
Excitatory potentials and postsynaptic potentials
Which type of potential can be generated by voltage gated ion channels ?
Action potentials
Types of electrophysiologic recording
Extra cellular
Intracelular
Single channel recording
What is a gigaseal ?
Seal that is formed between the patch-clamp electrode with the cell’s surface and interact with the membrane.
What is an on-cell Patch clamp?
Gigaseal with the cell membrane which measures single channel activity using a micropipette
How do we do an inside out patch and what does it measure?
Pull the patch of membrane off the cell and have access to the intracelular side of the patch
We can apply drugs and still record single channel activity
Name the versions of extracellular recordings
Field potentials
Whole nerve recordings
Multicellular recordings
Multi-unit recordings
Single unit recordings
MEAs
What cannot be recorded with extracellular recording methods?
Membrane potentials
Vm rest
Postsynaptic potentials
Difference between current clamp and voltage clamp
Current clamp “clamp” the cell potential at a chosen value. Measures ionic current at any given voltage
Voltage clamp records membrane potential. The membrane potential is free to vary.
How is a whole cell clamp made?
We break the membrane with the electrode still attached to the whole cell
Usefulness of whole cell clamp
Enables us to record from all ion channels in the membrane of a particular cell (whole cell recording)
How to made an outside out patch ?
Pull away the electrode from a whole cell patch pulling off a small patch of membrane exposing the outside of the membrane to the outside environment.
What is a perforated patch?
Diffuse an antibiotic to the membrane and forms pores
Usefulness of the perforated patch
You don’t lose things from the inside the cell and still get electrical activity
