Figure 9

Cholinergic administration produces a larger increase in hysteresis in VAD rats. The effects of cholinergic administration on pressure-volume hysteresis are shown for one representative VAS (A) and one representative VAD (B) rat. Solid line, prior to methacholine administration; broken line, immediately following methacholine administration. The mean ± SEM of the hysteresis ratio (C) was calculated for three VAS (open bars) and 3 VAD (checked bars) rats both before, and was significantly increased in VAD rats (p < 0.01, 1-way ANOVA, Student-Newman-Keuls post-hoc test) by cholinergic administration.