Aging does not alter the binding characteristics to voltage dependent calcium channels in the brain of CW1 mice

Structural age-related changes in cholinergic regions within the central nervous system of CW1 mice have been described previously. Since elevated calcium concentration has been suggested to play a role in the brain aging processes, the possible involvement of voltage dependent calcium channels in this degeneration was investigated. The binding characteristics of the calcium channel antagonist [3H](+)PN 200-110 to brains of aged CW1 mice were studied. This ligand exhibited high affinity binding (Kd values in the range of 50-70 pM) to a single type of sites with a density (Bmax) of 150-200 fmol/mg protein. No significant differences were observed between the binding parameters measured in young (3 months), mid-aged (9 and 15 months) and old (20 months) mice. Autoradiographic study confirmed these results and extended them to specific brain regions. It is concluded that age-dependent degeneration processes, observed histologically in specific brain regions of these mice, are probably not related to alterations in voltage-dependent calcium channels.