Characterization of α, β-Methylene ATP Binding Sites in Mouse Crude Synaptic Membranes

Abstract

Since ATP has been reported to be a potent excitatory transmitter in the mammalian central nervous system (CNS), we studied the neurochemical characters of the binding sites of α, β-methylene ATP, an agonist of P 2X receptors, in mouse crude synaptic membranes. ATP and its related compounds inhibited [ 3H] α, β-methylene ATP binding in a concentration-dependent manner. The potency order in the inhibition of the binding was as follows; α, β-methylene ATP = ADP βS > ATP γS > ATP ≥ ADP > β, γ-methylene ATP ⪢ UTP > 2-methylthio ATP. And adenosine did not affect the binding. The order was different from those reported in peripheral tissues. And Sr 2+, Ca 2+, Mg 2+, and Cd 2+ enhanced the binding. These results suggest that α, β-methylene ATP binding sites in CNS have different characters from those in peripheral tissues.