Skip to main content
. 2005 Jun 8;25(23):5623–5637. doi: 10.1523/JNEUROSCI.5305-04.2005

Figure 1.

Figure 1.

Postsynaptic injection of BAPTA, a rapid chelator of intracellular Ca2+, disrupts 5-HT-dependent facilitation of the sensorimotor synapse in culture. A, Representative EPSPs for each of the experimental groups. (The eliciting presynaptic action potentials are not shown in this or subsequent figures.) Trial times correspond to those indicated on the abscissa of the graph in B. B, Mean normalized amplitude of EPSPs in the three experimental groups: synapses treated with 5-HT without postsynaptic BAPTA (5-HT control; n = 8); synapses treated with 5-HT after BAPTA had been injected into the motor neuron (5-HT/BAPTA; n = 8); synapses that received the postsynaptic BAPTA injection but were not treated with 5-HT (test-alone/BAPTA; n = 8). A repeated-measures ANOVA for the trials during which 5-HT was present indicated that there was a significant main effect of experimental treatment (F(2,21) = 19.09; p < 0.0001) as well as a significant interaction (F(2,21) = 4.81; p < 0.02). Accordingly, one-way ANOVAs were performed on the 10 and 15 min trials, followed by Bonferroni's post hoc tests. The differences among the three experimental groups (5-HT control, 5-HT/BAPTA, and test-alone/BAPTA) were significant on the 10 min trial (F(2,21) = 11.36; p < 0.001). The mean normalized EPSP for the 10 min trial was 200 ± 25% in the 5-HT control group and 185 ± 24% in the 5-HT/BAPTA group; both values were significantly greater than that for the test-alone/BAPTA group (77 ± 5%; p < 0.003 for each comparison). The difference between the mean EPSP values in the 5-HT control and 5-HT/BAPTA groups was not significant for the 10 min trial. Analysis of the 15 min trial also revealed significant differences among the three experimental groups (F(2,21) = 17.23; p < 0.001). The mean normalized EPSP for the 5-HT control group for this trial (280 ± 42%) was significantly greater than the mean normalized EPSPs in both the 5-HT/BAPTA group (177 ± 20%) and the test-alone/BAPTA group (58 ± 6%; p < 0.05 for each comparison). The 5-HT/BAPTA EPSP was significantly greater than the test-alone/BAPTA EPSP (p < 0.02). A repeated-measures ANOVA performed on the group means for the 20-55 min trials indicated a significant main effect of experimental treatment (F(2,21) = 8.98; p < 0.002). SNK post hoc tests showed that the post-5-HT EPSPs in the 5-HT control group were significantly greater than those for both the 5-HT/BAPTA and test-alone groups (p < 0.05 for each comparison). The difference between the EPSPs in the 5-HT/BAPTA and test-alone groups, however, was not significant during the post-5-HT period. The asterisks indicate significant differences between the 5-HT control and 5-HT/BAPTA data, the # symbol indicates the significant difference between the 5-HT/BAPTA and test-alone data, and the crosses indicate significant differences between the 5-HT control and the test-alone data. Error bars represent SEM. Interstimulus interval, 5 min.