User
Guide
for
Axoclamp
900A
Replacing
the
Silver
Wire
To
replace
the
silver
wire,
insert
the
nonchlorided
end
through
the
hole
of
the
silicone
seal
and
bend
the
last
1
mm
of
wire
over
to
an
angle
of
90°.
Press
the
wire
into
the
back
of
the
barrel
making
sure
that
the
silicone
seal
is
flush
with
the
back
of
the
barrel.
Slip
the
threaded
collar
over
the
back
of
the
barrel.
Sharp
Microelectrode
Recording
The
HS
‐
9A
headstage
of
the
Axoclamp
900A
contains
a
voltage
‐
follower
circuit
that
is
activated
when
I=0
or
IC
(I
‐
Clamp)
mode
is
selected.
Although
the
I
‐
Clamp
circuit
is
designed
to
be
used
with
high
‐
resistance
sharp
microelectrodes,
it
can
also
be
used
with
lower
‐
resistance
patch
electrodes,
which
in
some
cases
offer
advantages.
In
this
chapter
it
is
assumed
for
the
most
part
that
sharp
microelectrodes
are
being
used
for
the
I
‐
Clamp
recording.
Microelectrode
Properties
Users
of
sharp
microelectrodes
spend
far
more
time
than
patch
clampers
worrying
about
the
properties
of
their
electrodes.
This
is
because
the
higher
resistance
of
sharp
microelectrodes
may
introduce
a
number
of
undesirable
properties.
For
best
results,
the
microelectrode
voltage
must
settle
rapidly
after
a
current
pulse,
and
the
microelectrode
must
be
able
to
pass
current
without
large
changes
in
resistance.
The
important
factors
that
need
to
be
considered
are
discussed
below.
Electrode
Glass
Borosilicate
glass
is
often
used;
however,
through
trial
and
error
one
type
of
glass
supplied
by
a
specific
glass
manufacturer
may
have
been
shown
to
yield
the
best
results.
It
is
suggested
that
the
literature
be
consulted
prior
to
selecting
glass
for
recording.
82
