Ion Channel Techniques

Question 1

How to calculate total current using patch-clamp methodology

Answer 1

I = inP0

i = current from single channel
n = # of channels
P0 = probability that a channel will be open

Question 2

P0 = ?

Answer 2

(sum of duration open / recording duration)

Question 3

Characteristics of channels

Answer 3

1. Characteristics size/conductance
2. Ion selectivity/permeability
3. Particular states
4. Distinct voltage sensitivity (some have none)
5. Distinct pharmacology

Question 4

Time-dependent activation

Answer 4

P0 increases with time

Question 5

Time-dependent inactivation

Answer 5

P0 decreases with time

Question 6

Magnitude and direction of charge flow through an ion channel depends on?

Answer 6

Electrochemical driving force