A(1) ADENOSINE RECEPTORS CAN OCCUR MANIFESTING 2 KINETIC COMPONENTS OF 8-CYCLOPENTYL-1,3-[H-3]DIPROPYLXANTHINE ([H-3]DPCPX) BINDING

The results described in this paper show, for the first time, that A(1 ) adenosine receptors can have two kinetic components for the binding of the antagonist [H-3]DPCPX. At low ionic strength (less than or equa l to 42 mmol/l), dissociation of [H-3]DPCPX bound to A(1) receptors fi tted better to a two kinetic components model than to a one kinetic co mponent model. The kinetic constants were consistent with comparable K -d values for the two components of the antagonist binding, and theref ore these two components cannot be distinguished by saturation isother m analysis.