Effect of the cytoskeletal fixation agent phalloidin on transcapillary albumin transport and interstitial fluid pressure following subdermal prostaglandin E1 administration in the rat

Aim: Lowering of interstitial fluid pressure (Pif) facilitates fluid filtration across the capillary membrane and oedema formation in acute inflammation. The cellular mechanism behind this lowering of Pif involves β1‐integrins mediating contact between dermal cells and the extracellular matrix fibres, and also the cell cytoskeleton as disruption of actin filaments using cytochalasin‐D induced a lowering of Pif and oedema formation. Fixation of actin with phalloidin attenuates oedema formation and abolishes lowering of Pif in anaphylaxis in the rat. The objective of this study was to determine whether phalloidin modifies lowering of Pif and albumin extravasation in rat skin also after prostaglandin E1 (PGE1). Methods: P if was measured using micropipettes connected to a servo‐controlled counterpressure system. Microvascular permeability was estimated as the albumin extravasation (Ealb) using radiolabelled human serum albumin. Results: Subdermal injection of PGE1 (0.85 mg mL−1) lowered Pif from −0.8 ± 0.8 mmHg (SD) in control to −3.5 ± 0.9 mmHg (P