I am attempting to do a NeuN stain on free-floating, gelatin embedded, paraformaldehyde fixed, 50 micron,vibratome cut sections of superior cervical ganglion. I am getting a small amount of positive staining after floating the sections for two days at room temperature, but I know that staining should be prolific. I use citric acid HIER on paraffin embedded sections with the same antibody and get very good results. The only type of retrieval the I currently use on the free floating sections is to incubate them in 0.4% Triton in PBS. Is there a non-heated antigen retrieval that can be used to good effect on free floating sections? I appreciate any and all input on this matter.