Introduction to Patch Clamp Electrophysiology

1
Introduction to Patch Clamp Electrophysiology

• Background
• Description
• What do the data look like?
• And what do they tell us?

2
Background receptors/ion channels
3
(No Transcript)
4

• from Unwin et al., 2003 animated by Colquhoun

5
Patch Clamp Technique

• Patch
• Clamp
• Electrophysiology

6
Electrophysiology Ohms Law

• V IR (V in volts, I in amps, R in ohms)
• I V/R
• I Vg (where g I/R g in siemens)

7
Description
8

The patch clamp consists of an electrode inside a
glass pipette. The pipette, which contains a salt
solution resembling the fluid normally found
within the cell, is lowered to the cell membrane
where a tight seal is formed. When a little
suction is applied to the pipette, the "patch" of
membrane within the pipette ruptures, permitting
access to the whole cell. The electrode, which is
connected to specialized circuitry, can then be
used to measure the currents passing through the
ion channels of the cell. Furthermore, we can use
our electrical circuitry to "clamp" the membrane
potential to any voltage that we desire very
handy when measuring the activity of
voltage-dependent channels.
9

• http//www.science-display.com/patchclamp.html

10
Microelectrodes
11
Looking through the microscope
12
Seals and patches

• Cell-attached gigaseal

13

• Whole-cell configuration

14
(No Transcript)
15
What the data look likeand what you can learn
16
I vs. V curves

• Ligand-gated
• ion channels

17

• Voltage-gated
• ion channels

18
Whole cell recording
19
(No Transcript)
20
(No Transcript)
21
(No Transcript)
22
(No Transcript)
23
Single channel recording
24
BC3H1 channels (pClamp)
25
Pharmacology GABA-R
26

• AChR

27

• The relationship
• between whole-cell
• and single channel