EXTRACELLULAR ADENOSINE-TRIPHOSPHATE - A SHOCK TO HEMATOPOIETIC-CELLS

Many or perhaps all cell types in the body possess extracellular binding sites for nucleosides and nucleotides, the purinoceptors. The binding sites that favor adenosine triphosphate (ATP) have been classified as P-2-purinoceptors. One subclass of the P-2-purinoceptors is the P-2Z-purinoceptor that mediates the permeabilizing effect of ATP(4-) (the fully ionized form of adenosine triphosphate). In the presence of millimolar concentrations of ATP(4-), this receptor, which was found on all cells of hemopoietic origin but not on cells of stromal origin, renders the sensitive cells permeable for molecules up to 1 kD. This property has been used to eliminate cells of hemopoietic origin from mixed populations. Skeletal- and blood-forming tissues have a complex cellular composition of predominantly stromal and hemopoietic cells. The 2 cell types influence each others' formation, differentiation, and activities in a largely unclarified manner. Rigorous separation would help the study of the properties and potencies of the 2 cell types and their mutual interactions. A short treatment of cell populations isolated from bone, bone marrow, or cartilage with 2 mM adenosine triphosphate and 1 mM of cytotoxic, but not permeant, potassium thiocyanate obliterates all cells of hemopoietic origin, including macrophages, osteoclasts, and their progenitors from these populations.