Tubulin and actin mRNAs in the young-adult and the aged rat brain: effects of repeated administration with bifemelane hydrochloride

In an attempt to identify the age-dependent changes in the potential synthesis of cytoskeletal proteins, we investigated changes in messenger RNA (mRNA) of α-tubulin and β-actin in the young-adult and the aged rat brain using Northern blot analysis. α-Tubulin mRNA levels in the frontal cortex and hippocampus, and β-actin mRNA levels in the hippocampus were significantly decreased in the aged rat brain. Age-dependent decreases in these mRNAs may be related to the neuronal dysfunction associated with aging, in addition to the reduction of several kinds of receptors previously reported. Repeated administration of bifemelane hydrochloride (4-(2-benzylphenoxy)-N-methylbutylamine hydrochloride) for 14 days increased the levels of β-actin mRNA in the frontal cortex and the striatum of both young-adult and aged rats, although the effect of bifemelane treatment was smaller and not significant in the aged group. These results suggest that bifemelane treatment may enhance the synthesis of cytoskeletal protein and promote neural plasticity by inducing neurite growth or synapse formation.