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. 2018 Mar 23;596(9):1549–1574. doi: 10.1113/JP275478

Figure 12. Neurally evoked mechanical responses of gastric fundus muscles from (+/+), iAno1+/– control and iAno1−/− animals.

Figure 12

A–D, typical mechanical responses from a (+/+) animal to demonstrate similarity in responses of tamoxifen treated iAno1+/– fundus muscles. A, under control conditions (no drugs), EFS (1–20 Hz for 30 s; 0.3 ms pulses) produced predominant relaxations at 1 Hz (left; horizontal bar) and a slight contraction followed by relaxation at 5 Hz (right; horizontal bar; dashed lines). B, in the presence of l‐NNA (100 μm), nerve evoked inhibitory responses to EFS were converted to excitatory responses at all frequencies tested. C, addition of neostigmine (1 μm) in the continued presence of l‐NNA caused an increase in basal tone and spontaneous contractile activity. EFS in the presence of neostigmine evoked large contractile motor responses at 1 and 5 Hz (dashed lines). D, excitatory motor responses were inhibited by atropine (1 μm) at 1 Hz and greatly attenuated at 5 Hz. E–H, mechanical responses to EFS of a tamoxifen treated iAno1+/– fundus were similar to (+/+) muscles (n = 8). E, under control conditions, EFS evoked an initial slight contraction followed by sustained relaxation at 1 and 5 Hz. F, in the presence of l‐NNA (100 μm), inhibitory responses were converted to excitatory responses at all frequencies tested. G, after addition of neostigmine (1 μm) in the continued presence of l‐NNA, there was an increase in spontaneous contractile activity and EFS evoked large contractile motor responses at 1 and 5 Hz. H, excitatory motor responses were inhibited by atropine (1 μm) at all frequencies of EFS tested. I–L, mechanical responses to EFS of a tamoxifen treated iAno1−/− fundus muscle. I, EFS evoked only slight relaxation responses at both 1 and 5 Hz. J, in l‐NNA (100 μm), there was reduced excitatory responses compared to (+/+) and iAno1+/– control muscles. K, neostigmine (1 μm) in the continued presence of l‐NNA produced large contractile responses similar to (+/+) and iAno1+/– fundus muscles. L, atropine added in the presence of l‐NNA and neostigmine inhibited EFS evoked contractile responses, suggesting that they were cholinergically mediated responses. M–P, summarized contractile responses of iAno1+/– (white bars; n = 8) and iAno1−/− animals (black bars; n = 20). M, EFS evoked responses under control conditions (no drugs added). Both inhibitory and excitatory responses were recorded. N, after addition of l‐NNA, EFS evoked excitatory responses were noted in both animal groups; however, the fundus responses of tamoxifen treated iAno1−/− animals were reduced significantly (* P < 0.05, one‐way ANOVA). O, after the addition of neostigmine, contractile responses were markedly increased in both animal groups, and there was no significant difference in responses between both animals. P, after the addition of atropine, there was a marked reduction in EFS evoked responses in gastric fundus muscles from both animal groups.