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. 2013 Jan 21;591(Pt 6):1489–1506. doi: 10.1113/jphysiol.2012.247684

Figure 3. Non-nitrergic, non-purinergic (NNNP) relaxation develops slowly during longer stimulus trains in WT mice and persists beyond the end of the stimulus train.

Figure 3

A, sample traces showing inhibition of contraction with 5 Hz EFS for 60 s (Aa) or 20 Hz EFS for 30 s (Ab) in control conditions (grey traces) and following addition of l-NNA (100 μm) plus MRS2500 (1 μm; black traces). B, summary graphs of the effects during 5 Hz EFS for 60 s (Ba) or during 20 Hz EFS for 30 s (Bb) on contractile activity in control conditions (5 Hz, n = 9; 20 Hz, n = 8), with MRS2500 (5 Hz, n = 5; 20 Hz, n = 5) or with combined addition of l-NNA and MRS2500 (5 Hz, n = 9; 20 Hz, n = 9). In the presence of l-NNA and MRS2500, relaxation during EFS begins after approximately 20 s of EFS at 5 Hz and 15 s of EFS at 20 Hz. C, sample traces of post-stimulus relaxations following 5 Hz (left) or 20 Hz (right) EFS with increasing stimulus train length. Neither the control relaxation during EFS nor the post-stimulus relaxation following EFS (Ca) is reduced by MRS2500 (1 μm) alone (Cb), while l-NNA (100 μm) plus MRS2500 greatly attenuates relaxation during EFS but not post-stimulus relaxation (Cc). D, summary graphs of post-stimulus relaxations following various stimulus train lengths in control conditions at 5 Hz (Da, n = 5–11) or 20 Hz (Db, n = 7–9) or in the presence of l-NNA plus MRS2500 (Dc, 5 Hz, n = 11–13; Dd, 20 Hz, n = 6–11). Post-stimulus relaxation significantly increased (*p<0.05) with increasing stimulus train length (one-way ANOVA with Tukey's post hoc test). Shown are mean values ± SEM.