Vascular barrier-enhancing effect of an endogenous beta-adrenergic agonist.
Exogenous catecholamines have been proved to be active in the reduction of vascular permeability induced by various inflammatory mediators via beta-adrenoceptor activation, but it is not known whether an endogenous beta-adrenergic agonist has any effect. We studied it in skin and lung vessels. The results revealed that an intravenous bolus of isoproterenol (10 micrograms/kg) attenuated platelet-activating factor- and histamine-induced Evans blue dye extravasation in rat dorsal skin, while intraperitoneal administration of beta-adrenoceptor blocker propranolol (0.1 mg/kg) significantly increased the dye extravasation. Blockade of beta-adrenoceptor by propranolol for 12 h noticeably increased wet/dry lung weight ratio, lung water content, bronchoalveolar lavage (BAL) protein concentration, leukocyte count, and lipoperoxide degradation product malondialdehyde (MDA) content. In isolated perfused lung in vitro, propranolol (2.5 micrograms/ml) had no obvious effects on lung weight gain, fluid filtration coefficient, and pulmonary vascular pressure during the 20-min perfusion compared with control. The results suggested that endogenous beta-adrenergic agonist is an important factor in the maintenance of vascular integrity and the quiescent state of leukocytes, indicating the antiinflammatory role of catecholamines in physiological states and critical illnesses.
Ding
Z
Z
Department of Pathophysiology, Second Military Medical University, Shanghai, PR China.
Jiang
M
M
Li
S
S
Zhang
Y
Y
D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000818:Animals; D002199:Capillary Permeability / Q000187:drug effects*; D066298:In Vitro Techniques; D046911:Macromolecular Substances; D008833:Microcirculation / Q000187:drug effects; D010477:Perfusion; D011433:Propranolol / Q000494:pharmacology; D011652:Pulmonary Circulation / Q000187:drug effects; D011654:Pulmonary Edema / Q000139:chemically induced; D051381:Rats; D017207:Rats, Sprague-Dawley; D012867:Skin / Q000098:blood supply
D000318:Adrenergic beta-Agonists; D046911:Macromolecular Substances; D011433:Propranolol