The actions of platelet activating factor include the following except:

PLATELET ACTIVATING FACTOR (PAF) Like eicosanoids, platelet activating factor (PAF) is a cell membrane derived polar lipid with intense biological activity. The types of cells which synthesize PAF is quite limited--mainly WBC, platelets, vascular endothelium and kidney cells. Actions:- Blood vessels:- Vasodilatation mediated by release of EDRF occurs - fall in BP on i.v. injection. Decreased coronary blood flow has been observed on intracoronary injection, probably due to formation of platelet aggregates and release of TXA2. PAF is the most potent agent known to increase vascular permeability. Wheal and flare occur at the site of intradermal injection Visceral smooth muscle:- Contraction occurs by direct action as well as through release of LTC4, TXA2 and PGs. Aerosolized PAF is a potent bronchoconstrictor. Stomach:- PAF is highly ulcerogenic: erosions and mucosal bleeding occur sholy after i.v. injection of PAF. The gastric smooth muscle contracts. Ref:- kd tripathi;pg num:-190,191