Morphological Changes in the Hyalomere of Rat Blood Platelets in Experimental Venous Thrombi

Abstract

The fine structure of rat blood platelets aggregated in experimentally produced thrombi was examined by light‐ and electron microscopy after glutaraldehyde fixation. In the ‘body’ regions of the thrombi two kinds of platelet aggregates, arranged in irregular but distinct zones, could be distinguished. In one of the zones platelets were totally degranulated and appeared as nearly empty sacs. In the other zone degranulation was less extensive, and fine, approximately 50 Å thick filaments were a prominent feature of the hyaloplasm. Microtubules were present in the hyaloplasm of platelets in both zones. The filaments and the microtubules are suggested as possible morphological substrates of the contractile proteins known to be present in platelets.