Ligand-mediated regulation of kinin receptors in the rabbit.
The kinin B1 receptors (B1Rs), stimulated by des-Arg9-kinins, are completely inducible, notably following treatment of animals with bacterial lipopolysaccharide. Several studies based on cultured cells have suggested a form of autoregulation of kinin receptors, because B2 receptor (B2R) or B1R stimulation could transcriptionally upregulate B1R expression. The B2R may rather be downregulated in inflammatory conditions. A rabbit B2R-green fluorescent protein (GFP) conjugate stably expressed in HEK 293 cells was rapidly internalized in response to the agonist bradykinin. Ligand-induced receptor cycling was documented applying confocal microscopy. The results confirm agonist-induced B2R endocytosis, but extensive recycling to the cell membrane does not support agonist-induced downregulation.
Centre Hospitalier Universitaire de Québec, Centre de recherche, Pavilion l'H tel-Dieu de Québec, Quebec City, Canada.
F
F
Marceau
A
A
Adam
S
S
Houle
J
J
Bouthillier
M
M
Bachvarova
D R
DR
Bachvarov
D000818:Animals; D003513:Cycloheximide / Q000494:pharmacology; D004705:Endocytosis / Q000187:drug effects; D049452:Green Fluorescent Proteins; D006801:Humans; D007202:Indicators and Reagents; D007705:Kinins / Q000378:metabolism*; D008024:Ligands; D008164:Luminescent Proteins; D010766:Phosphorylation; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D011817:Rabbits; D011956:Receptors, Cell Surface / Q000502:physiology*; D014407:Tumor Cells, Cultured; D015854:Up-Regulation / Q000187:drug effects
D007202:Indicators and Reagents; D007705:Kinins; D008024:Ligands; D008164:Luminescent Proteins; D011500:Protein Synthesis Inhibitors; D011956:Receptors, Cell Surface; D049452:Green Fluorescent Proteins; D003513:Cycloheximide