Using STAINperfect immunostaining kit A, Tryptophan was detected within the hindbrain of embryonic mouse E15.5 following the protocol for whole mount samples (image on left, red). Serotonin, a tryptophan metabolite, was detected in the raphe nucleus from adult mice on floating sections prepared with the STAINperfect immunostaining kit A. Stainings were performed using anti-Tryptophan Mouse monoclonal Ab (IS011) and Serotonin Rabbit polyclonal Ab (IS1007). Fluorescent conjugated secondary antibodies were used and images acquired by confocal imaging.