Manoukian R, et al. - In order to assess the downstream molecular mechanisms following ligand-receptor blockade by which monoclonal antibodies prevent calcitonin gene-related peptide (CGRP) signaling through CGRP receptors, researchers produced tool monoclonal functional antagonist antibodies against CGRP and its canonical receptor. In addition, using fluorogen-activated protein technology, a novel cellular model was developed that enables detection of CGRP receptor internalization by flow cytometry and, for an extended time course, visualization by confocal microscopy. Using the cell model, they noted blocking of both CGRP-induced cyclic adenosine monophosphate (cAMP) signaling and CGRP receptor internalization by these antagonist antibodies. To block CGRP receptor internalization, there is a necessity for at least 10-fold higher concentrations of either antibody compared with cAMP accumulation in this cell model. Data thereby strengthen the understanding how CGRP signaling is affected by monoclonal functional antagonist antibodies.