Figure 12. Mechanical activity of the longitudinal muscle layer of the gastric antrum from wild-type and W/W^V mutant animals.

A–D, mechanical activity of the longitudinal muscle layer of the gastric antrum of a wild-type animal in response to EFS. A, responses to nerve stimulation (0.3 ms 5–20 Hz, for 10 s, arrows) under control conditions. During EFS, there was advancement in the phasic contraction immediately following EFS and a slight increase in the amplitude of the phasic contraction. B, after the addition of l-NA (100 μm), there was little or no change in the mechanical response to EFS. C, atropine (1 μm) also had little or no effect on EFS-induced contractions. D, TTX inhibited the increase in phasic contractions to EFS and the advancement in the phasic mechanical activity immediately after EFS (except at 20 Hz). E–H, mechanical activity of the longitudinal muscle layer of the gastric antrum of a W/W^V mutant animal in response to EFS. E, responses to nerve stimulation (0.3 ms 5–20 Hz, for 10 s, arrows) under control conditions. EFS phase advanced mechanical activity at 10 Hz or greater. F, l-NA (100 μm) had little effect on spontaneous activity or on EFS-evoked nerve activity. G, in the presence l-NA and atropine (1 μm), EFS still evoked a phase advancement of mechanical activity at frequencies of 5 Hz or greater. H, the phase advancements in contractions observed at 10 Hz and greater were inhibited by TTX (1 μm).