Effect of Prenatal Protein Malnutrition on Birthdates and Number of Neurons in the Rat Locus Coeruleus.

The effect of prenatal protein deprivation on the timing of neurogenesis and on the number of neurons generated in the locus coeruleus of the rat was studied. These neurons are of interest as their axon projections are involved in the earliest stages of cerebral cortical development. Dams were maintained on a 25% casein diet or a 6% casein diet five weeks prior to mating and the diets continued throughout the pregnancy. At birth, all pups were cross-fostered to dams on a 25% casein diet. BrDU, a thymidine analog that is incorporated into the nuclear DNA during the synthetic phase of the cell cycle, was used as a marker of the generation period. It was administered intraperitoneally (25 mg/kg body weight) on embryonic day 10, 11, 12, 13, or 14. On postnatal day 30, the brain stems were processed with BrDU immunocytochemistry to determine the relative number of neurons generated on each day, and with Nissl stain to determine the total number of neurons generated in the two groups. There were no significant differences between the two diet groups in the timing of their generation or in the total number of neurons generated, indicating a preservation of neurogenesis of these early generated neurons in these malnourished rats.