Figure 4.

The paired-pulse synaptic plasticity is apparently eliminated when nicotinic agonist ABS coexists with either 5-CT or CPA. (A,B) (Left) Representative paired-pulse AMPAR current traces recorded from the same neuron in the absence (control, black lines) and presence (green lines) of 3 μM ABS plus 10 nM 5-CT (A) or 3 μM ABS plus 10 μM CPA (B). Each trace is the average of three consecutive trials. Stimulus artifacts are omitted. (Right) Summary plot of the 1st EPSC and the 2nd EPSC in drug relative to that in control and PPR in drug (n = 5). The concentrations used are 10 nM, 10 μM, and 3 μM for 5-CT, CPA, and ABS, respectively. The interstimulus interval is 50 ms. Some data of single drugs are from Figure 1. ^**p < 0.01, compared between the effects with and without the addition of ABS by Student's unpaired t-test. See also Figure S1 for the data from individual experiments. (C) Plot of the averaged PPR vs. ISI for the control condition (open circles, n = 10, data from Figure 3) compared to the simultaneous presence of combined drugs (black circles, n = 5). The curve is a fit for the control data of the form: PPR = 0.815[1-exp (t/166.7)]. The dashed horizontal lines indicate the levels where PPR or relative EPSC equals 1.