What are ion channels and how to study them Flashcards
1
Q
What are ion channels?
A
- Pore or channel formed from proteins that lies across the lipid cell membrane
- Allows flow of ions (K+, Na+, Ca2+, Cl-) IN/OUT of the cell
2
Q
What does voltage gated ion channel mean?
A
- When charge on membrane is depolarised (negative to positive internal change)
- Transmembrane protein opens
- Allows ions to flu inside/outside e.g., Na, K
3
Q
What are ligand gated ion channels?
A
- Known as ionotropic receptors
- Group of proteins which open to allow ions to pass through
- In response to the binding of a chemical messenger e.g., ligand e.g., neurotransmitter
4
Q
What are mechanosensitive ion channels?
A
- Found in all types of cells
- Respond to membrane tension/stimuli by altering their shape between open and closed
- e.g., Piezo-1 blood vessel volume sensors
5
Q
What are TRP channels?
A
- Transient receptor potential channels
* Responsible for depolarisation in response to light/temperature/ligands
6
Q
Why study ion channels?
A
- Wide ranging and critical physiological roles
- Gene expression
- Sensory perception – senses come through ion channels
- Physiological rhythms = sleep-wake cycle + heart rate
- They are important drug targets
7
Q
What are ion channel diseases
A
- Channelopathies
* Human disorders
8
Q
How to study ion channels OLD
A
- Manual patch clamp
- Use a microscope – look at an ion channel
- Push electrode onto cell
- Measure the current generation by a single cell upon stimulation
9
Q
CONS of manual patching
A
- Time consuming and slow
- Have to use microscope
- Cells stay in one place
- Have to move electrode
- Technical and complex
10
Q
How to study ion channels NEW
A
- Automated patch clamp
- Move the cell to an array of electrodes
- Multiple electrodes available
11
Q
PROS of automated patch clamp
A
- Simplifies ion channel recording
- Faster
- Can do multiple recordings
