Research Article

An Inotropic Action Caused by Muscarinic Receptor Subtype 3 in Canine Cardiac Purkinje Fibers

Figure 3

Influences of caffeine pretreatment on ACh- or Iso-evoked positive inotropy in canine cardiac Purkinje fibers. (a) Typical tracings of the inhibitory effects of caffeine on ACh-evoked inotropy or Iso-evoked inotropy. (b) Pooled data of effects of pretreated caffeine on ACh or Iso-evoked positive inotropy. Columns show the percent increase in contractile force in the presence of caffeine 1 or 3 mM, and vertical bar indicates SEM ( ). significantly different from control values before ACh or Iso application (paired Student’s t-test or Wilcoxon’s t-test).