Figure 3.

Long-term functional and structural changes evoked by one pulse of 5-HT paired with injection of ApCREB2 antiserum. (A) Summary of the structural and functional changes induced by one pulse of 5-HT. Injection of the ApCREB2 antiserum paired with one pulse of 5-HT 24 hr later results in a significant enhancement of the EPSP amplitude and a concomitant significant increase in the number of varicosities. (B) Examples of structural changes evident 24 hr after one pulse of 5-HT paired with injection of ApCREB2 antiserum. The fluorescent micrographs taken from the same regions of sensory neurites contacting the axon hillock of L7 before (1 and 3) and 24 hr after treatment (2 and 4). Arrows in 2 illustrate examples of some of the new varicosities present 1 day after one pulse of 5-HT paired with the injection of the ApCREB2 antiserum. The EPSPs, evoked before (0 hr) and after (24 hr) one pulse of 5-HT in the pictured neurons are indicated in the insets. (Bar = 20 μm.) [Reproduced with permission from Bartsch et al. (27) (Copyright 1995, Cell Press).]