3H-thymidine long survival autoradiography as a method for dating the time of neuronal origin in the chick embryo: The locus coeruleus and cerebellar Purkinje cells
Article first published online: 9 OCT 2004
Copyright © 1981 Alan R. Liss, Inc.
Journal of Comparative Neurology
Volume 203, Issue 2, pages 257–267, 1 December 1981
How to Cite
Yurkewicz, L., Lauder, J. M., Marchi, M. and Giacobini, E. (1981), 3H-thymidine long survival autoradiography as a method for dating the time of neuronal origin in the chick embryo: The locus coeruleus and cerebellar Purkinje cells. J. Comp. Neurol., 203: 257–267. doi: 10.1002/cne.902030207
- Issue published online: 9 OCT 2004
- Article first published online: 9 OCT 2004
Contrary to previous assumptions, we have found that a single dose of 3H-thymidine (25 μCi), injected into the yolk sac of White Leghorn chick eggs on 2 days of incubation (d.i.) only remains available for DNA-synthesizing (proliferating) cells for 48 hours following the time of injection. This finding now makes it possible to date the time of neuronal origin in the avian embryo using a single injection of isotope and a long survival time (30 days posthatch) as in mammalian studies where 3H-thymidine is only available as a short “pulse.” Using this method, we have determined that neurons in the chick locus coeruleus (LC) cease proliferation on 2–6 d.i. with a peak of neuronal genesis on 3–5 d.i. In addition, neuronal genesis is not homogeneous throughout the LC cell population, but occurs in a predominantly caudorostral gradient. Conversely, the cerebellar Purkinje cells cease division on 3–8 d.i. with a peak of heavy labeling on 4–6 d.i., 1 day later than that observed in the LC.