Differential sensitivity of [3H]nitrendipine binding to cations of toxicological interest in various rat brain areas.

[3H]Nitrendipine ([3H]NTP) is a radiolabelled calcium antagonist which can be used to study neuronal calcium (Ca2+) channels. The interaction of Mn2+, Zn2+, Pb2+ and La3+ on [3H]NTP binding was studied in 3 brain areas particularly rich in [3H]NTP binding sites. Differences were observed in the brain regional distribution of [3H]NTP binding as well as in their sensitivity to the metal ions Pb, Mn and Zn. The binding data suggest that neuronal Ca2+ channels in different brain areas display distinct sensitivity to selected divalent cations.