Effect of catecholamines on oedema induced by inflammatory agents in the rat.

The effect of intracutaneous adrenaline and noradrenaline (5 X 10(-12) and 5 X 10(-11) mol) was examined on the oedema (Evans blue dye leakage) response of rats to several inflammatory agents. The catecholamines reduced the oedema response to all agents tested except prostaglandin E1 (PGE1) which was significantly potentiated by noradrenaline (5 X 10(-11) mol), and a combination of bradykinin 5 X 10(-11) mol with PGE1 5 X 10(-10) mol which was not significantly affected by any dose of catecholamine. Adrenaline was more effective than noradrenaline in reducing oedema produced by 5-hydroxytryptamine (5HT) and histamine and by agents which release these amines (compound 48/80, dextran and antigen challenge with egg albumin in sensitized rats), but noradrenaline was more potent against bradykinin-induced oedema. The inhibitory effect of catecholamines against oedema produced by histamine and 5HT was abolished by a combination of phentolamine and propranolol. It was concluded that the oedema-inhibiting effect of catecholamines is due to alpha- and beta-adrenoreceptor mediated actions.