Modulation of [(35)S]GTPgammaS binding to chinese hamster ovary cell membranes by D(2(short)) dopamine receptors

• Published in: Neuroscience letters Vol. 280; no. 2; pp. 135 - 138
• Main Authors: Terasmaa, A, Finnman, U B, Owman, C, Ferré, S, Fuxe, K, Rinken, A
• Format: Journal Article
• Language: English
• Published: Ireland 18.02.2000
• Subjects: Animals; Basic Medicine; Binding, Competitive - drug effects; Butaclamol - pharmacology; CHO Cells; Cricetinae; Dopamine - pharmacology; Dopamine Antagonists - pharmacology; Dopamine D2 Receptor Antagonists; Dose-Response Relationship, Drug; Guanosine 5'-O-(3-Thiotriphosphate) - metabolism; Guanosine Diphosphate - pharmacology; Medical and Health Sciences; Medicin och hälsovetenskap; Medicinska och farmaceutiska grundvetenskaper; Membranes - drug effects; Membranes - metabolism; Neurosciences; Neurovetenskaper; Raclopride - metabolism; Raclopride - pharmacology; Radioligand Assay; Rats; Receptors, Dopamine D2 - genetics; Receptors, Dopamine D2 - physiology; Spiperone - analogs & derivatives; Spiperone - pharmacology; Sulfur Radioisotopes; Tritium
• ISSN: 0304-3940
• DOI: 10.1016/S0304-3940(00)00776-X

Rat dopamine D(2short) expressed in Chinese hamster ovary (CHO) cells were characterized by means of activation of [(35)S]-guanosine 5'-O-(gamma-thiotriphosphate) ([(35)S]GTPgammaS) binding and inhibition of [(3)H]raclopride binding. Among 18 dopaminergic ligands studied dopamine, NPA, apomorphine and quinpirole were full agonists in activation of [(35)S]GTPgammaS binding, while seven ligands were partial agonists with efficacies from 16 to 69% of the effect of dopamine and seven ligands were antagonists having no effect on the basal level of [(35)S]GTPgammaS binding, but inhibited dopamine-dependent activation in a dose-response manner. Despite the different efficacies, the potencies of all 18 ligands to modulate [(35)S]GTPgammaS binding revealed a good correlation with their potencies to inhibit [(3)H]raclopride binding in the CHO cell membranes. This indicates that the binding of the ligand to the receptor determines its potency, but has no direct correlation with its intrinsic activity.