Effects of Perfluoroisobutene on Guinea Pig Isolated Lung Preparations.

Abstract : Effects of perfluoroisobuteno (PFIB) on lung pharmacology were investigated using three preparations: The isolated, ventilated, perfused lung (IVPL), the tracheally-perfused lung (TPL) and the tracheal strip (TS). The IVPL taken from PFIB exposed animals showed decreased tidal volume (TV) and compliance (Cdyn), and increased lung resistance (LR), but no PFIB-induced chemical mediator release was detected by bioassay. in vitro inhalation exposure of the IVPL to PFIB caused a dose-related, reversible bronchoconstriction (increased L(R), decreased TV and Cdyn) within 1-5 minutes; no mediator release was detected by bioassay. A greatly diminished bronchoconstriction occurred following a second exposure to PFIB, suggesting that PFIB may stimulate the release of an exhaustible mediator that produces bronchoconstriction but does not produce a response in the bioassay tissues. The mediator may initiate responses which lead to pulmonary oedema. The TPL removed from PFIB-exposed guinea pigs showed increased sensitivity to 5-hydroxytryptamine, bradykinin, isoprenaline and a thromboxane A2 analogue, but not to carbachol, histamine, prostaglandin D2, adenosine or potassium. These changes were not detected in the TS. If PFIB-induced changes in lung pharmacology contribute to oedema, antagonists of identified mediators may be useful as pretreatments/therapies to pulmonary oedemagens.