Properties of binding sites for [3H]cyclohexyladenosine in the hippocampus and other regions of rat brain: a quantitative autoradiographic study.
The properties of binding sites for the adenosine receptor ligand, [3H]cyclohexyladenosine ([3H]CHA), were investigated in rat brain using quantitative autoradiography. Scatchard analysis of the binding data showed that there were no significant differences between Kd values for [3H]CHA in any of the regions investigated. The highest concentrations of [3H]CHA binding sites were found in the cerebellum (molecular layer) and the stratum oriens and stratum radiatum of the hippocampus (CAI region). Displacement curves obtained using N-ethylcarboxamidoadenosine (NECA) and the R- and S-diastereoisomers of phenylisopropyl adenosine (PIA) showed the [3H]CHA binding sites to have the pharmacological properties of A1-adenosine receptors, i.e. the order of potency for these derivatives was R-PIA greater than NECA greater than S-PIA, in all regions tested. Further, [3H]CHA binding was in all cases attenuated by the guanosine triphosphate derivative, beta, gamma-imidoguanosine triphosphate. These results indicate that [3H]CHA binding sites throughout the central nervous system have the properties of A1-adenosine receptors and that these are in all regions associated with guanine nucleotide regulatory proteins.
D000241:Adenosine / Q000031:analogs & derivatives* / Q000378:metabolism; D019830:Adenosine-5'-(N-ethylcarboxamide); D000818:Animals; D001345:Autoradiography; D001667:Binding, Competitive; D001921:Brain / Q000378:metabolism*; D006624:Hippocampus / Q000378:metabolism; D010660:Phenylisopropyladenosine / Q000378:metabolism; D051381:Rats; D011956:Receptors, Cell Surface / Q000378:metabolism*; D011983:Receptors, Purinergic; D013237:Stereoisomerism
D011956:Receptors, Cell Surface; D011983:Receptors, Purinergic; D010660:Phenylisopropyladenosine; D019830:Adenosine-5'-(N-ethylcarboxamide); C027513:N(6)-cyclohexyladenosine; D000241:Adenosine