Figure 6.
The effect of the specific antagonist of EX-4, exendin (9-39). (A) Plot of the normEXC in an experiment in which 100 nM exendin (9–39) (e) was applied for 30 min before 50 nM EX-4 (30 min, E) and the final long-term application of LPS (3 μg/ml). The continuous line is the fixed threshold. (B) Plot of cumBD in control (thick line), in the presence of exendin (9–39) (closed asterisk), or EX-4 added on top (open asterisk) and in LPS after 7 h (rightward triangles). The vertical arrow indicates the fixed threshold. The four curves were tested with the non-parametric Wilcoxon signed rank test analysis (exendin (9-39) vs. control, P < 10−5; LPS 7 h vs. control, P < 10−10; EX4 vs. exendin (9–39), P = 0.32). The GLP1-R antagonist blocked the protective effect of EX-4 observed in Figure 5, allowing the late excitatory responses to LPS to be expressed.