Modification of adrenergic reactivity in rat tail artery by dietary lipids and calcium channel antagonists

1. The antiatherosclerotic activity of dihydropyridines (DHP), potent calcium antagonists, was studied with respect to prevention of hypercontractility of perfused rat tail arteries. 2. Used for 1 month, atherogenic diet increased pressor responses to norepinephrine (NE) in Ca(2+)-free physiological salt solution (PSS), and PSS containing Ca(2+). 3. When nifedipine (NIF) or nitrendipine (NIT) was administered simultaneously with an atherogenic diet, the contractile activity of NE in Ca(2+)-free PSS was attenuated. Moreover, vasoconstrictor responses to NE in PSS containing Ca2+ were inhibited after 1-month treatment with NIT and nimodipine (NIM). 4. NIF, NIT and NIM prevented atherosclerosis-induced vascular hyperreactivity to alpha-adrenoceptor agonists in rat tail artery.