Xercise Primes a Molecular Memory for Brain-derived Eurotrophic Factor Protein Induction in the Rat Ippocampus

bstract—Exercise is an important facet of behavior that nhances brain health and function. Increased expression of he plasticity molecule brain-derived neurotrophic factor BDNF) as a response to exercise may be a central factor in xercise-derived benefits to brain function. In rodents, daily heel-running exercise increases BDNF gene and protein evels in the hippocampus. However, in humans, exercise atterns are generally less rigorous, and rarely follow a daily onsistency. The benefit to the brain of intermittent exercise s unknown, and the duration that exercise benefits endure fter exercise has ended is unexplored. In this study, BDNF rotein expression was used as an index of the hippocampal esponse to exercise. Both daily exercise and alternating ays of exercise increased BDNF protein, and levels progresively increased with longer running duration, even after 3 onths of daily exercise. Exercise on alternating days was as ffective as daily exercise, even though exercise took place nly on half as many days as in the daily regimen. In addition, DNF protein remained elevated for several days after exerise ceased. Further, after prior exercise experience, a brief econd exercise re-exposure insufficient to cause a BDNF hange in naïve animals, rapidly reinduced BDNF protein to evels normally requiring several weeks of exercise for inducion. The protein reinduction occurred with an intervening rest” period as long as 2 weeks. The rapid reinduction of DNF by an exercise stimulation protocol that is normally ubthreshold in naïve animals suggests that exercise primes molecular memory for BDNF induction. These findings are linically important because they provide guidelines for opimizing the design of exercise and rehabilitation programs, n order to promote hippocampal function. © 2005 Published y Elsevier Ltd on behalf of IBRO.