Biology Reference
In-Depth Information
Dissecting instruments (forceps, retractors, scissors—including
micro-scissor like the Vanna Spring Scissor No 15002-08 from
Fine Science Tools for cutting the dura and vessels).
Cauterizer.
Stereotaxic frame.
Micro drill and drill bits.
Micromanipulators for placement of electrodes and measuring
devices.
Perfusion pump (for aCSF superfusion/drug application).
Monitoring
:
Homeothermic blanket system with temperature probe.
Pressure transducer and cable (e.g.: BLPR2, WPI).
General-purpose amplifi er.
CO
2
analyzer (e.g.: CapStar-100 End-Tidal CO2 analyzer; CWE).
Personal computer with data acquisition system.
Blood gas analyzer.
Special equipment
:
Microelectrodes (see below and Chap.
29
)
.
Amplifi er, AD converter, and data acquisition/analyzing software
for electrophysiological recordings.
rCBF measuring device (see below).
2.2. Artifi cial
Cerebrospinal Fluid
aCSF should be prepared freshly on the day of the experiment. We
use aCSF in a composition of (in mM) 152 Na
+
, 3 K
+
, 1.5 Ca
2+
, 1.2
Mg
2+
, 24.5 HCO
3
−
, 135 Cl
−
, 6.7 urea, and 3.7 glucose. The aCSF
is equilibrated with a gas mixture containing 6.6% O
2
, 5.9% CO
2
,
and 87.5% N
2
to yield a pH of 7.38-7.40, a
p
O
2
between 110-
125 mmHg, and a
p
CO
2
of 35-39 mmHg (substances from Sigma
Aldrich, Germany, for example).
Ion-sensitive microelectrodes are used to measure extracellular ion
concentration changes [K
+
, Ca
2+
, Na
+
, Cl
−
, tetrapropylammonium
(size of the extracellular space) or pH] in conjunction with mea-
surement of the intracortical, extracellular direct current (DC)
potential and high-frequency local fi eld potentials (measured
against a reference electrode (Ag/AgCl wire or 5-mm disc elec-
trode) placed subcutaneously in the neck) (Fig.
1
). Fabrication of
ion-selective glass microelectrodes is described in Chap.
29
.
If ion
changes are not of interest, single-barrel electrodes can be used for
electrophysiological recordings of the extracellular fi eld potential.
In case of an intact dura preparation, epidural high-frequency elec-
trocorticogram (ECoG) and DC potential can be measured with a
simple Ag/AgCl wire attached to the dura. A polyethylene tube is
2.3. Microelectrodes
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