Rockefeller University

About: Rockefeller University is a education organization based out in New York, New York, United States. It is known for research contribution in the topics: Population & Gene. The organization has 15867 authors who have published 32938 publications receiving 2940261 citations. The organization is also known as: Rockefeller University & Rockefeller Institute.

Maturation and Death of Adult-Born Olfactory Bulb Granule Neurons: Role of Olfaction

Abstract: Young neurons born in the subventricular zone (SVZ) of adult mice migrate to the olfactory bulb (OB) where they differentiate into granule cells (GCs) and periglomerular interneurons. Using retroviral labeling of precursors in the SVZ, we describe five stages and the timing for the maturation of newly formed GCs: (1) tangentially migrating neuroblasts (days 2-7); (2) radially migrating young neurons (days 5-7); (3) GCs with a simple unbranched dendrite that does not extend beyond the mitral cell layer (days 9-13); (4) GCs with a nonspiny branched dendrite in the external plexiform layer (days 11-22); and (5) mature GCs (days 15-30). Using [3H]thymidine, we show that the maximum number of labeled GCs is observed around day 15 after injection. Interestingly, between days 15 and 45 after birth, soon after the cells developed spines, the number of [3H]thymidine-labeled GCs declined by 50%. Using anosmic mice, we found that sensory input was critical for the survival of GCs from day 15 to 45 after labeling. However, the number and morphology of 15-d-old cells in the granule cell layer was similar in anosmic and wild-type mice. We infer that the lack of activity did not have an effect on the generation, migration, and early differentiation of granule cells. Soon after young GCs matured, and presumably became synaptically connected, their survival depended on the level of activity that they received. This selection mechanism might allow the construction of specific OB circuits based on olfactory experience and suggests possible functions of OB cell replacement.

Effects of stress on immune cell distribution. Dynamics and hormonal mechanisms.

Abstract: Immune cell trafficking is crucial to the performance of the surveillance as well as effector functions of the immune system Because immune cells travel between tissues through the bloodstream, the numbers and proportions of leukocytes in the circulation provide an important representation of the state of leukocyte distribution in the body The studies described here examine significant and selective changes in numbers and percentages of peripheral blood leukocyte subpopulations in the rat These changes were rapidly induced under conditions of mild acute stress Stress-induced increases in plasma corticosterone were accompanied by a significant decrease in numbers and percentages of lymphocytes, and by an increase in numbers and percentages of neutrophils flow cytometric analysis revealed that B cell, NK cell, and monocyte numbers showed a greater stress-induced decrease than did T cells All stress-induced changes were observed during the light (inactive) as well as the dark (active) period of the animal's diurnal cycle Importantly, the stress-induced changes in leukocyte numbers and percentages were rapidly reversed upon the cessation of stress Furthermore, the effects of stress were largely dependent on adrenal hormones, because the magnitude of the stress-induced changes was significantly reduced in adrenalectomized animals Moreover, administration of corticosterone to adrenalectomized animals resulted in a close replication of stress-induced changes observed in adrenal-intact animals These results suggest that endocrine factors released during stress modulate leukocyte trafficking and result in the redistribution of leukocytes between the blood and other immune compartments Such a redistribution may significantly affect the ability of the immune system to respond to potential or ongoing immune challenge