Hernandez-Morato I, et al. - Given the up-regulation of Netrin-1 and glial cell-derived neurotrophic factor (GDNF) expression in laryngeal muscles during recurrent laryngeal nerve (RLN) regeneration, researchers sought to ascertain the timing of the production of Netrin-1 and GDNF receptors during RLN regeneration. Further, they assessed the correlation of this timing with the previously identified timing of up-regulation of their trophic factors in the laryngeal muscles. In this laboratory experiment with rat model, they transected the right RLN and applied dextran amine tracer. They removed and harvested brainstems at 7, 14, and 21 days postinjury (DPI). Performing immunostaining for Netrin-1 (deleted in colorectal carcinoma [DCC], UNC5A) and GDNF receptors (rearranged during transfection [Ret], glycosylphosphatidylinositol-linked cell surface receptors [GFRα1, GFRα2, GFRα3]), they identified a higher production of Netrin-1 DCC and GDNF receptors in the nucleus ambiguus when RLN was injured. In the laryngeal muscles, the timing of receptor production is similar to up-regulation of their trophic factors.