The development of alkaline phosphatase in trichinous muscle.

The development of alkaline phosphatase during invasion and encystment of Trichinella spiralis in rat skeletal muscle fibres was studied at the ultrastructural level. On day 14 after infection, the enzymatic activity is found in proliferating parts of the T-tubular system and in parts of the plasmalemma. In cells, in which a strong hyperplasia of this system is noted. AlPase is present in the abundant network of stratified and concentric membranes from which a large number of pinocytic vesicles arise. From day 50 till 1 year after infection the enzyme activity was invariably present in the matrix surrounding the larvae and was confined to the enormous amounts of cytoplasmic membranes. The possible functional significance of this enzyme in the matrix, in view of its peculiar localization in the immediate vicinity of the parasite, is discussed. In the presence of 0.1 mM of the levamisole analogue, compound R 30402, which is a stereospecific inhibitor of AlPase, the activity is completely lost.