Fig. 1.

H₂NOH facilitates LTP induction. A 25-pulse stimulus train delivered at either 10 or 50 Hz (A) produced only short-term potentiation in slices bathed in normal ACSF (open symbols). In the presence of 200 μm H₂NOH (filled symbols), both 10 and 50 Hz HFS produced potentiation that was still significant after 60 min. H₂NOH was washed in 20 min before tetanus, and washed out 5 min after tetanus (horizontal line in A). A 25-pulse stimulus at 50 Hz was delivered to nine additional slices in control ACSF (B). As in A, responses returned to baseline after 60 min. H₂NOH was washed onto these same slices for 20 min (horizontal line in B), followed by repetition of the 50 Hz HFS, which this time produced significant enhancement of the field EPSP slope, which lasted at least 60 min after the tetanus. Error bars in all figures represent SEM.