Interaction of agonist peptide [3H]Tyr-D-Ala-Phe-Phe-NH2 with mu-opioid receptor in rat brain and CHO-mu/1 cell line.
Opioid receptor binding properties of [3H]Tyr-D-Ala-Phe-Phe-NH2 (TAPP) were characterized in rat brain and Chinese hamster ovary (CHO) cells expressing the rat mu-receptor. In rat brain, [3H]TAPP labeled a single class of opioid sites with a dissociation constant (Kd) of 0.31 nM and maximal number of binding sites (Bmax) of 119 fmol/mg protein. In CHO-mu/1 cell membranes, the Kd and Bmax values were 0.78 nM and 1806 fmol/mg protein, respectively. Binding to rat brain was demonstrated to be pharmacologically identical to that obtained with CHO-mu/1 cell membranes and modulated by Na+ ions and guanine nucleotides. The high affinity and selectivity of [3H]TAPP together with its low non-specific binding make this radioligand a useful tool for labeling the native and cloned mu-opioid receptor.
Institute of Biochemistry, Biological Research Center Hungarian Academy of Sciences, Szeged, Hungary.
M
M
Spetea
F
F
Otvös
G
G
Tóth
T M
TM
Nguyen
P W
PW
Schiller
Z
Z
Vogel
A
A
Borsodi
D000818:Animals; D001921:Brain / Q000378:metabolism*; D016466:CHO Cells; D006224:Cricetinae; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D004745:Enkephalins / Q000378:metabolism; D006165:Guanylyl Imidodiphosphate / Q000378:metabolism; D008024:Ligands; D009842:Oligopeptides / Q000378:metabolism*; D051381:Rats; D017450:Receptors, Opioid, mu / Q000819:agonists* / Q000378:metabolism; D014316:Tritium / Q000378:metabolism
D004745:Enkephalins; D008024:Ligands; D009842:Oligopeptides; D017450:Receptors, Opioid, mu; C103476:tyrosyl-alanyl-phenylalanyl-phenylalaninamide; D014316:Tritium; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D006165:Guanylyl Imidodiphosphate