부산대학교 도서관

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.bbrc.2008.10.117 Byline: Kristoffer Sahlholm, Daniel Marcellino, Johanna Nilsson, Kjell Fuxe, Peter a'rhem Keywords: Dopamine D.sub.2 receptor; Dopamine agonists; Voltage-sensitivity; Voltage-clamp; G protein-coupled receptor; Xenopus oocytes; Phenethylamines; Aminotetralins Abstract: Recently, we and others have shown that agonist potencies at some, but not all, G protein-coupled receptors are voltage-sensitive. Several of those studies employed electrophysiology assays in Xenopus oocytes with G protein-coupled potassium channels as a readout. Using this assay, we have now obtained evidence that voltage-sensitivity at the dopamine D.sub.2S receptor is agonist-specific. Whereas the potency of dopamine at the D.sub.2S receptor is decreased by depolarization, the potencies of [beta]-phenethylamine, p- and m-tyramine are voltage-insensitive. Furthermore, both monohydroxylated and non-hydroxylated N,N-dipropyl-2-aminotetralin compounds are voltage-sensitive. Differential activation of G protein subtypes or differential ratios between effector and active G protein do not underlie this agonist-selective voltage-sensitivity. This is the first demonstration of voltage-sensitive and voltage-insensitive behaviour of different agonists acting via the same receptor. Author Affiliation: Department of Neuroscience, Karolinska Institutet, SE-171 77 Stockholm, Sweden Article History: Received 18 October 2008