Effects of Monastral((R)) blue on pulmonary arterial blood pressure and lung and liver particle retention in chickens

The effects of intravenous administration of the vascular tracer Monastral( R) blue (MB) on pulmonary arterial blood pressure and the retention of MB b y lung and liver were assessed in anesthetized White Leghorn cocks. Pulmona ry arterial blood pressure and systemic blood pressure were measured by dir ect cannulation. Administration of MB alone had no effect on either pulmona ry arterial blood pressure or systemic arterial blood pressure; however, fo llowing pretreatment with endotoxin (ENDO), infusion of MB caused a rapid a nd transient increase in pulmonary arterial blood pressure. Histological ex amination of lungs and liver from these animals showed a greater accumulati on of MB in liver than in lung, in which virtually no MB was observed by li ght microscopy. The relative amounts of MB in lung and liver were measured by atomic emission spectrophotometry in animals given MB alone and followin g ENDO pretreatment, In either case the total amount of MB retained by the lungs was less than 2% of the injected dose, whereas liver retention of MB was approximately 88% in those birds given MB alone and 80% in those pretre ated with ENDO. The results of this study suggest that chickens do not poss ess reactive pulmonary intravascular macrophages (PIMS), as, in those speci es in which reactive PIMS are present, injection of MB alone causes a marke d increase in pulmonary arterial blood pressure and substantial lung retent ion of the tracer.