Figure 7.

Concentration–response curves to p-tyramine (a) and β-phenylethylamine (β-PEA; b) in the absence (no antagonist) and the presence of all antagonists (propranolol, 1 μM; prazosin, 10 μM; ketanserin, 3 nM; methiothepin, 50 nM; haloperidol, 0.7 nM and mepyramine, 2 μM) constructed in porcine coronary arterial rings with intact endothelium. Data are means±s.e.mean from 4 to 14 separate experiments, expressed as a percentage of the response to 60 mM KCl. When no error bar is shown, the error is smaller than the symbol. ^*P<0.05 and ^**P<0.01 indicate significant differences from the control (p-tyramine or β-PEA in the absence of antagonist).