Ontogenic appearance of Ca2+ channels characterized as binding sites for nitrendipine during development of nervous, skeletal and cardiac muscle systems in the rat

The appearance of specific receptors for the Ca2+ channel antagonist nitrendipine has been followed during the fetal and post-natal development of rat brain without cerebellum, cerebellum, skeletal muscle and cardiac muscle. The number of nitrendipine receptors is low at the fetal stage and increases drastically during post-natal development of brain, cerebellum, skeletal muscle and cardiac muscle. The time course of this increase is different for each type of tissue studied. No significant change in receptor ligand dissociation constant (Kd) can be detected over the development period studied. The results are discussed in relation with the known properties of the differentiation process in the four types of excitable tissues studied.