title: Beta-adrenoceptor stimulating effects of phenylephrine and noradrenaline in the rat pulmonary vascular bed.
abstract: The effects of phenylephrine and noradrenaline have been investigated on the perfusion pressure of the rat isolated lung. Both drugs (0.3-30 micrograms) produced a dose-dependent decrease in perfusion pressure elevated by 20 mM KCl, which was reversed to a dose-dependent increase after addition of propranolol (1 x 10(-7) M) to the perfusion fluid. Increments due to both agonists in the presence of propranolol were antagonized by prazosin (1 x 10(-6) M). Propranolol, but not prazosin, elevated the basal perfusion pressure. The results indicate that phenylephrine and noradrenaline are more effective in stimulating beta-adrenoceptors than alpha-adrenoceptors in the rat pulmonary vascular bed and that beta-adrenoceptors may regulate the vascular tone of the rat pulmonary circulation.
mesh_terms: D000318:Adrenergic beta-Agonists; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D066298:In Vitro Techniques; D008168:Lung / Q000378:metabolism; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism*; D009638:Norepinephrine / Q000494:pharmacology*; D010656:Phenylephrine / Q000494:pharmacology*; D011189:Potassium Chloride / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D011652:Pulmonary Circulation / Q000187:drug effects; D051381:Rats
chemical_list: D000318:Adrenergic beta-Agonists; D010656:Phenylephrine; D011189:Potassium Chloride; D011433:Propranolol; D009638:Norepinephrine; D011224:Prazosin