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. Author manuscript; available in PMC: 2015 Dec 24.
Published in final edited form as: Bladder (San Franc). 2015 Jul 17;2(2):e15. doi: 10.14440/bladder.2015.44

Figure 3. Effect of ZD7288 on phasic contractions in absence of Tetrodotoxin (TTX).

Figure 3

A. Typical traces of isometric tension recording from urothelium intact rat bladder strips. Cumulative addition of a non-selective blocker of HCN channels, ZD 7288 produced a concentration dependent increase in phasic detrusor contractions (red tracing), whereas Lamotrigine, which is known to activate HCN channels, caused a modest decrease in phasic contractions (blue tracing). In each trace, the timing of cumulative drug application is shown by arrowheads, and vehicle (DMSO) had no effect. The effect of Lamotrigine was blocked when HCN blocker ZD7288 was constantly present in the bath at the fixed conc. of 10-5 M (purple tracing), demonstrating that relaxant effect of Lamotrigine is dependent on opening of HCN channels. B. Comparison of ZD7288 (Δ), Lamotrigine (□) and combination of two drugs (∇) for effects on normalized integrated mechanical activity. The relaxant effect of Lamotrigine was reversed in the presence of ZD 7288(∇). Ordinate Scale is total integrated mechanical activity (above baseline) normalized to the activity recorded prior to drug application, which is defined as 100% (corresponds to arbitrary point of 10-10 M on x-axis). Each point in (B) represents mean ± SEM of 4–5 strips. ZD7288 caused moderate decrease in the relaxant effect of Lamotrigine [10-9 M] by 4.72 ± 0.79% and that of Lamotrigine [10-4 M] by 15.36 ± 4.24% (*P < 0.05; two-way ANOVA followed by a Bonferroni multiple comparison post hoc test). The y-axis is in two segments 0–100 and 100–300 to indicate the divergent effect of Lamotrigine and ZD7288.