Interaction of bovine platelets with bovine glomerular basement membrane.

The interaction of bovine platelets with bovine glomerular basement membrane has been studied by aggregometry, transmission and scanning electron microscopy and measurement of [3H] serotonin release. In the absence of added calcium platelets adhere to basement membrane but fail to undergo the release reaction or aggregation. In the presence of 0.2-0.5 mM calcium release of serotonin and complete aggregation of the platelets are observed when sufficient basement membrane is present. Platelets were strongly adhered to the basement membrane surface, the platelet surface in the aggregates closely following the surface of the basement membrane. Platelet morphology in aggregates with basement membrane closely resembled that of platelets from collagen-induced aggregates. Basement membrane differed from collagen in its requirement for calcium for the aggregation and release reactions. In addition purified basement membrane was 1.5-3 fold less active on a weight basis than bovine tendon collagen in promoting aggregation.