The ontogeny of specific binding sites for the calcium channel antagonist, nitrendipine, in mouse heart and brain.

The high specific activity radioligand, [3H]nitrendipine, was used to study the ontogeny of high affinity binding sites in mouse heart and brain. A period of rapid postnatal brain growth is reflected by a dramatic increase in the receptor density (Bmax) between 7 and 21 days of age, reaching an adult Bmax value of 10.7 +/- 0.38 fmol/mg tissue. A more linear rise in cardiac binding site density to 16.8 +/- 2.0 fmol/mg tissue was found while no change in Kd of either tissue was noted during development.