Biology Reference
In-Depth Information
A
Patch-clamp
amplifier
Patch pipette
Ion
channel
Reference
electrode
Bath
B
Cell-attached
Whole-cell
Outside-out
Inside-out
C
IP
3
K
+
500 ms
C
O1
O2
Fig. 1
Conventional patch-clamp recording. (A) A polished glass pipette forms a tight seal against a
biological membrane isolating an area across which the tiny currents passing through small numbers of
open channels can be recorded. (B) Di
V
erent configurations of conventional patch-clamp recording.
Beginning with a cell-attached patch, an inside-out excised patch can be produced by pulling the patch-
pipette away from the cell, while suction or a strong brief voltage-pulse ruptures the underlying
membrane to give the whole-cell configuration. An outside-out patch can then be produced by pulling
the patch-pipette away from the whole-cell configuration. (C) Typical whole-cell recordings of IP
3
R3
expressed in the plasma membrane of DT40-KO cells expressing rat IP
3
R3. PS included IP
3
(10
m
M),
ATP (5 mM), and a free [Ca
2
þ
]of
200 nM; K
þ
was the charge carrier and the holding potential was
100 mV. C, O1, and O2 show the closed state and the openings of 1 and 2 IP
3
R, respectively.
