[3H]Nitrendipine bound to cerebral cortex membranes is displaced more efficiently by verapamil in old rats (24 months old) compared to young ones (3 months old). In addition, [3H]verapamil binding was studied in detail in 3-, 12- and 24-month-old rats. Aging increases the Bmax of [3H]verapamil, leaving the affinity unchanged. These observations further indicate that aging may affect calcium channels leading to a derangement of calcium movements which in turn alter neuronal activity.