Effect of Corticosterone on Developing Hippocampus: Short-Term and Long-Term Outcomes

Many documents implicate that corticosterone plays a negative role in brain function, especially in learning and memory. However, less evidence confirms its direct actions on hippocampal development. In the work reported here, pro treatment, minimum corticosterone administration in infant mice, and con treatment, corticosterone deprivation by adrenalectomy, were used to examine the effects imposed by corticosterone on the structure and function of developing hippocampus. Our study shows that adrenalectomy induces decrease of plasma corticosterone levels and results in the impairment of learning performance and the degenerative changes not in CA regions of hippocampus but in dentate gyrus. Noteworthily, this damage effect is severer in 5-week-old mice than that in 10-week-old mice. In addition, the short-term effect of minimum corticosterone administration may accelerate the development of dentate gyrus of 10-day-old mice. Moreover, minimum corticosterone administration during infancy contributed to the learning performance and the structural integrity of hippocampal CA regions in different developing stages, while this phenomenon was not observed in dentate gyrus. In conclusion, corticosterone is necessary for the development of dentate gyros, especially in relatively young individuals, and administration with minimum corticosterone in infancy has a long-term positive influence on the hippocampal structure and function in different developing stages. (C) 2008 Wiley-Liss, Inc.