An Inotropic Action Caused by Muscarinic Receptor Subtype 3 in Canine Cardiac Purkinje Fibers
Effects of ACh on contractile force in canine cardiac Purkinje fibers. (a) Concentration-response relationships of the ACh-evoked positive inotropic effects in canine cardiac Purkinje fibers. Fibers were exposed in 1.8 mM Tyrode’s solutions. Circles with vertical bars indicate the mean ± SEM (). (b) Biphasic responses of single application of ACh 10−4 M. Columns with vertical bars indicate the mean ± SEM (). Each point shows the rates of changes versus control, and statistical significance was performed using raw data. , significantly different from control values ((a) one-way repeated measures ANOVA; (b) paired Student’s t-test).