Background: Accumulative evidences suggest that any change in brain neurotrophins can be involved in brain development and function. However, little is known about age related alteration of the neurotrophins. In this experimental study, we investigated the adulthood changes in the locomotor activity and the levels of Nerve Growth Factor (NGF) and Brain Derived Neurotropic Factor (BDNF) in selected brain regions of mice.

Methods: In this experimental twelve adult mice at 4 and 6 months of age were used and open filed test was performed to determine animal's locomotor activity.  Hippocampus, cerebellum and cortex of the animals were isolated under deep anesthesia, and levels of NGF, BDNF and total protein were measured from extracts of tissues at the end of 4th and 6th months of age.

Results: Animals with 6 months of age were significantly hyperactive. We found a significant reduction for NGF in hippocampus (35.7%, p= 0.002), cerebral cortex (31.8%, p= 0.012), cerebellum (51.8%, p= 0.001) and for BDNF in hippocampus (11.2%), cerebral cortex (29.6%). However, BDNF level significantly increased in cerebellum (2.25 fold, p= 0.003) with age rising from four to six months. BDNF level were the highest in the hippocampus at the age of 4 months.

Conclusion: These results suggest that the sustained decrease of NGF and BDNF proteins in brain regions may be involved in the adulthood brain development.