Figure 7.
Limiting the influence of IMI-CCAP in LG to the protractor phase does not mimic the action of bath-applied CCAP on the gastric mill rhythm in a computational model. A, Gastric mill rhythm, driven only by MCN1 stimulation. The black bar represents the retractor phase duration. B, Gastric mill rhythm resulting from MCN1 stimulation during the continually present influence of CCAP. Note the prolongation of the LG burst (protraction) and unchanged duration of the LG interburst (retraction) relative to A. The black bar represents the retractor phase duration in A. C, Selectively providing IMI-CCAP to the gastric mill protractor phase changed the CCAP influence on the MCN1-gastric mill rhythm by prolonging retraction as well as protraction. Note that the retractor phase is prolonged relative to the black bar that represents the retractor phase duration in the control conditions. Most hyperpolarized Vm (A–C): LG, −73 mV. D, Providing IMI-CCAP during protraction consistently prolongs both gastric mill phases, causing an increased gastric mill cycle period relative to the saline and continually present IMI-CCAP conditions. Black bars, Saline condition; gray bars, continually present IMI-CCAP; white bars, IMI-CCAP present during protraction only; *p < 0.05, **p < 0.01, ***p < 0.005; n.s., not significant.