Biology Reference
In-Depth Information
1.4. Limitations
Anesthesia effects: Intracellular recording is performed on animals
under anesthesia and fi xed on stereotaxic frames. The effects of
anesthetics on neuronal activity and synaptic transmission should
be taken into consideration with data interpretation. For example,
ketamine has effects on NMDA receptor, which might have func-
tional consequences on glutamate receptor-mediated synaptic
transmission under physiological condition and on excitotoxic cell
death in neurological disorders. Therefore, the data from intracel-
lular recording should be integrated with results obtained from
other techniques, such as recording from freely moving animals
and behavior studies, to avoid misinterpretation.
Complex neuronal network effects: The advantage of in vivo
recording is the preservation of the intact neuronal system.
However, due to the complex neuronal circuit and the intercon-
nections between neurons, the evoked postsynaptic potentials
(PSPs) recorded by in vivo recordings are the combination of
excitatory (EPSPs) and inhibitory PSPs (IPSPs). Sometimes, the
weak IPSPs are masked by the strong EPSPs or vice versa.
Therefore, the EPSPs or IPSPs evoked by a specifi c pathway
should be carefully examined and confi rmed before reaching the
conclusions.
2. Patch-Clamp
Recording on
Brain Slices
Brain slice preparation was developed in 1930s (
10
) and electro-
physiological recording from brain slices has been conducted since
1960s (
11
). Introduction of patch-clamp recording technique in
the mid 1970s revolutionized the fi eld and moved the neuroscience
research to a new level (
12
).
Whole-cell patch-clamp recording on brain slices is an important
technique for measuring transmembrane currents and voltages
of the neuron in a controlled environment. It could be used to
compare the alterations of neuronal activity and synaptic transmis-
sion (inhibitory and excitatory) following neurological injury.
It could also be used to identify the electrophysiological mecha-
nisms involved in the pathological processes by manipulating
extracellular and intracellular environments during recordings.
For instance, this technique has been applied to investigate the
changes of ion channel activity and synaptic transmission after
cerebral ischemia (
13, 14
) and following traumatic brain injury
(
15
). In this chapter, the practical procedures for performing
whole-cell recording on brain slices are introduced. For more
detailed description of the patch-clamp recording techniques,
please refer to other excellent books chapters (
16, 17
).
2.1. Introduction
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