Effect of calcium ionophore A23187 on platelet adherence.

Adherence of platelets occurs irregularly after application of calcium ionophore A23187. Platelet adhesion could be observed in individual experimental animals 15 minutes after application of calcium ionophore (20 μM). In 2 cases of the control preparations (○), and 1 case each of animals bearing LLC-1 (▾) and BFS-1 (), platelets adhere onto the luminal surface of microvessels for 30 seconds. Effects were more pronounced in postcapillary venules of controls than in tumor microvessels. Median, n = 6 to 8 microvessels per experimental animal.