The binding of [3H]R-PIA to A1 adenosine receptors produces a conversion of the high- to the low-affinity state.
Kinetic evidence for negative cooperativity on the binding of [3H]R-PIA to A1 adenosine receptors was obtained from dissociation experiments at different ligand concentrations and from the equilibrium isotherm. The dissociation curves indicate that there is an apparent ligand-induced transformation of high- to low-affinity states of the receptor. At concentrations of 18.2 nM R-PIA or higher there was only found the low-affinity state of the receptor. In view of these results equilibrium binding data were analyzed by the usual two-state model (assuming that there is an interconversion between them) and by the negative cooperativity model employing the Hill equation.
Casadó
V
V
Departament de Bioquimica i Fisiologia, Facultat de Quimica, Barcelona, Catalunya, Spain.
Mallol
J
J
Canela
E I
EI
Lluis
C
C
Franco
R
R
D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D066298:In Vitro Techniques; D007700:Kinetics; D010660:Phenylisopropyladenosine / Q000378:metabolism*; D011983:Receptors, Purinergic / Q000378:metabolism*; D012044:Regression Analysis; D013552:Swine
D011983:Receptors, Purinergic; D010660:Phenylisopropyladenosine