Fig. 2.

Histamine increases endothelial permeability and decreases the transendothelial electrical resistance (TEER). The decrease in TEER is inhibited by the Ca²⁺ chelator BAPTA, the calmodulin inhibitor trifluoperazine (TFP), and the MLCK inhibitor ML-7 (van Nieuw Amerongen et al. 1998). The right panel gives a schematic representation of the mechanism by which histamine increases MLC phosphorylation and actin-non-muscle–myosin interaction. An additional effect of histamine on junctional stability remains possible.