The effects of chemically and electrically-induced convulsions on [3H]nitrendipine binding in mouse brain.

The effects of chemically and electrically-evoked seizures on [3H]nitrendipine binding to voltage-dependent calcium channels in mouse brain were determined 30 and 60 min following the initiation of convulsions. While maximal electroconvulsive shock, pentylenetetrazol and strychnine exhibited either no or marginal effects, Ro 5-4864 produced a decrease (14%) in the Bmax of [3H]nitrendipine at 30 min but not 60 min. The convulsant dihydropyridine calcium channel activator, BAY K 8644, produced a significant increase in the Kd (31%) of [3H]nitrendipine at 30 min, and a significant increase in both the Bmax (21%) and Kd (28%) of [3H]nitrendipine 60 min following the initiation of convulsions. While maximal electroconvulsive shock, pentylenetetrazol and strychnine exhibited either no or marginal effects, Ro 5-4864 produced a decrease (14%) in the Bmax of [3H]nitrendipine at 30 min but not 60 min following the initiation of convulsions. These findings indicate that modulation of voltage-dependent calcium channels by certain convulsants may be important in the genesis of seizures or in post-ictal compensatory processes.