Axon MultiClamp 700A User Manual

40 • Guide to Electrophysiological Recording
MultiClamp 700A Theory and Operation, Copyright 2000, 2001 Axon Instruments, Inc.
the capacitance transient appears, but be prepared to quickly release the suction as soon
as this occurs so the cell is not sucked up into the electrode.
The MultiClamp 700A contains a Zap circuit to aid in breaking into the cell. This
circuit delivers a pulse of 1 V DC to the patch for variable durations ranging from 0.1
to 10 ms. Start with the Zap duration at 1 ms then depress the Zap button in the
MultiClamp Commander. A successful break-in will again look like that in Figure 3.2.
If the patch is not disrupted, the Zap duration can be increased and the Zap applied a
second time, and so on. Some investigators have found that the application of
moderate suction while the Zap pulse is given results in a higher incidence of
successful patch disruption. The reappearance of the original rectangular pulse either
means that you have lost the seal or that the cell does not have a large input resistance.
It is not unusual for small cells to have an input resistance of several gigohms but with
active conductances it might be as low as a few tens of megohms.
300 pA
2 ms
SEAL
ADJUST F AST M AG
AND FAST
τ
GO WH OLE CE LL
Figure 3.2. Going whole-cell: capacity transients observed when rupturing the patch.

Axon MultiClamp 700A Specifications

General

Brand	Axon
Model	MultiClamp 700A
Category	Amplifier
Language	English