Resting platelets adhere on A23187-activated mesenteric venules.

Calcein AM-labeled platelets were visualized in mesenteric venules using a fluorescent microscope. Fluorescent resting WT platelets were transfused into WT recipient mice and began to adhere to the endothelium 15 seconds after topical superfusion of the calcium ionophore A23187. The adhesion process reached a maximum between 30 seconds and 1 minute and progressively decreased with time. Platelet aggregation was not observed. Arrowheads indicate the edge of the mesenteric venule. Arrow points to a fluorescent platelet adhering to the vessel wall. Bar, 75 μm.