Acetylcholinesterase distribution in subpopulations of murine thymocyte.

The presence of acetylcholinesterase has been detected in the thymus of several species both biochemically and histochemically. In this study we have investigated the molecular forms and the level of this enzyme in separate compartments of the murine thymus and in different thymocyte subpopulations. Similar levels of acetylcholinesterase activity are present both in thymocytes and in the stromal component. Sucrose density gradient analysis revealed the presence of a single molecular form of about 5 S, presumably a dimeric form. Moreover the results demonstrate a preferential association of AChE with mature thymocyte subsets (Peanut Agglutinin negative and Corticoresistant). This finding correlates with the preferential sensitivity of these cells to cholinergic drugs and supports the hypothesis that acetylcholinesterase modulates the cholinergic effects on thymocytes.