The influence of pycnogenol on the probability of contraction was studied in chick cardiomyocytes. Ventricles from 9-11 day chicken embryos were cultured.
After 10-11 days in culture, stable spontaneous contractions were recorded and the contraction kinetics analysed. Isoproterenol and pycnogenol increased the probability of the contraction state. After pretreatment with the β-receptor antagonist, propranolol reduced the isoproterenol- and pycnogenol-increased probability of contraction state. These data suggested that pycnogenol has inotropic effects via stimulation of β-receptor mediated activity.