Figure 4.

Concentration–response curves to p-tyramine (a) and β-phenylethylamine (β-PEA; b) in the absence and the presence of endothelium in porcine coronary arterial rings. Data are means±s.e.mean from four separate experiments, expressed as a percentage of the response to 60 mM KCl. When no error bars are shown, the error is smaller than the symbol. There were no significant differences between the responses at any of the concentrations tested.