Antibodies reveal the cytolocalization and subunit structure of the 1,4-dihydropyridine component of the neuronal Ca2+ channel.
Rabbit brain synaptosomes bind the 1,4-dihydropyridine derivative (+)[3H]-PN 200-110 with an equilibrium dissociation constant of 0.04 nM and a maximal binding capacity of 400 fmol/mg of protein. Using polyclonal antibodies raised against the different components of the skeletal muscle 1,4-dihydropyridine receptor, we have demonstrated that the brain and muscle receptors share the same subunit composition comprising a large polypeptide chain of Mr 140,000 associated by disulfide bridges with a smaller peptide of Mr 32,000. These antibodies have been used in immunofluorescence staining of brain sections. They reveal a distribution of the Ca2+ channel protein similar to that of 1,4-dihydropyridine binding sites with (+)[3H]PN 200-110 by the autoradiographic technique.
D000818:Animals; D000906:Antibodies; D001345:Autoradiography; D001921:Brain / Q000166:cytology; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels; D005455:Fluorescent Antibody Technique; D007163:Immunosorbent Techniques; D007473:Ion Channels / Q000378:metabolism*; D017275:Isradipine; D007700:Kinetics; D008970:Molecular Weight; D009132:Muscles / Q000378:metabolism; D009474:Neurons / Q000378:metabolism*; D010069:Oxadiazoles / Q000378:metabolism*; D011817:Rabbits; D011978:Receptors, Nicotinic / Q000378:metabolism; D013574:Synaptosomes / Q000378:metabolism; D014018:Tissue Distribution
D000906:Antibodies; D015220:Calcium Channels; D007473:Ion Channels; D010069:Oxadiazoles; D011978:Receptors, Nicotinic; D002118:Calcium; D017275:Isradipine