Electrophysiology and Morris Water Maze to Assess Hippocampal Function After Experimental Subarachnoid Hemorrhage - Animal Models of Acute Neurological Injuries: Injury and Mechanistic Assessments - page 397

Fig. 1. Electrode placement on hippocampal slice. Recording electrode on the cell layer of
CA1 and stimulating electrode in the stratum radiatum of CA3.

2.3. Electro-
physiological
Recording

Transfer a slice from the tissue chamber to the recording chamber
on the stage of the microscope and superfuse the slice with
oxygenated artifi cial CSF at a constant fl ow rate of 1.2 ml/
min. Let the slice settle for 10 min.
Pull the glass capillary tubing with Flaming/Brown micropipette
puller to make recording electrode and fi ll it with either artifi -
cial CSF or 150 mM NaCl.
Place the stimulating bipolar tungsten electrode in the stratum
radiatum of CA3.
To record the fi eld potentials extracellularly from CA1, place the
recording glass electrode approximately 300 m away from the

stimulating electrode in the cell layer of CA1 (Fig. 1 ).
Record basic neurotransmission by stimulating the Schaffer col-
lateral pathway using a pulse range from 10 to 300

μ

μ A at a rate

of 0.05 Hz to fi nd the maximum response.
To examine LTP, record the baseline for 30 min by stimulating the
pathway with the pulse intensity that gives 30-40% of the
maximum EPSP at the rate of 0.05 Hz.
Induce LTP by stimulating the CA3-CA1 pathway with high fre-
quency stimulation (HFS) consisting of 4 trains of 100 pulses
at 100 Hz with an inter-train interval (ITI) of 1 min.
Record the post-HFS response for 2 h.
The signal is amplifi ed, digitized and then acquired using a personal
computer with Clampex 8 software running.