Rapid appearance of labeled degenerating cells in the dorsal root ganglia after exposure of chick embryos to tritiated thymidine.

The interval between [3H]thymidine delivery and onset of cellular degeneration in 5.5 day embryonic chick brachial dorsal root ganglia was examined autoradiographically. Of the degenerating cells, 14% were labeled by 2 h after [3H]thymidine delivery. This percentage increased for 24 h. Wing bud amputation had no effect on this percentage through 9 h. Thus, some cause of cell death other than faulty peripheral connections may exist in at least some degenerating ganglionic cells.