Dye-coupling between pyramidal cells of rat hippocampus in vivo

Lucifer Yellow was intracellularly injected into pyramidal cells of rat hippocampus in vivo. In 10 successful staining experiments there were 5 cases of dye-coupling, in which 2-4 cells were stained though only one was injected. These results indicate that dye-coupling and, therefore, presumably electrotonic coupling, occurs between neurons of the hippocampus in the whole animal and confirms previous findings in the hippocampal slice in vitro.