Reatividade bronco-alveolar e vascular ahistamina no pulmão isolado do cobaio: efeitos de diversos tratamentos farmaeológíeos e imunológicos

Abstract

In an experimental model of asthma in perfused lungs of guinea pigs sensitized with ovalbumin and of normal guinea pigs, the effects of adrenergic blockers, cicloxigenase inhibitors, activators and inhibitors of EDRF synthesis and local an- aesthetics, on brocho-pulmonaiy endothehum and broncho-vascular reactivity, were investigated. Adult guinea-pigs from both sexes were anaesthetized with pentobarbital (40 mg/ml) by intraperitoneal route. Tracheostomy was done, the lungs were removed and perfused with Krebs-Henseleit solution, at 37 °C, in a non-recirculating system composed of a perfusion pump, a device to measure the perfusion pressure and a pulmonary chamber. Pulmonary functional parameters, such as pulmonaiy perfusion pressure, bronchial resistance and perfusate flow, were studied. These parameters were also measured “in vitro” during the anaphylatic reaction in lungs isolated from guinea- pigs previously sensitized with ovoalbumin. Ip all the groups studied, histamine injections were given (50, 100, 200, 400 pg/ml) in bolus and a significant increment in the usually low perfusion pressure was verified. In one of the groups, albumin (0.25%) was added to the perfusate. Compared to the control group, the results of the bronchial resistance did not. show statistical difference. We also verified that the perfusion pressure parameter was significai! tly increased.