FIG. 6.

Diagram showing the sequence of mechanical compression, release, and application of 4-aminopyridine (4-AP). (A) Each ventral white matter strip was compressed to 80% (20% of its original thickness) and the compression was maintained for 30 min. Then decompression was performed by removing the compression rod from the tissue. Thirty minutes after decompression, the cord was treated with 100 μM 4-AP for an additional 30 min. The compound action potential (CAP) amplitude was continuously monitored from pre-compression to 30 min after 4-AP was washed away with oxygenated Krebs solution. In one category of the experiment, the ventral white matter strip was compressed briefly (i.e., decompression was performed immediately after the strip was compressed to 80%, without sustained compression; # denotes when voltage tests were performed throughout the series of experiments). (B) Examples of individual CAP amplitude recorded in pre, sustained compression, recovery, 4-AP, and wash periods.