Comparison of molecular properties of the voltage-sensitive Ca2+ channel from longitudinal smooth muscle of rabbit ileum with the channel purified from transverse tubules of rabbit skeletal muscle.
Dihydropyridine-sensitive calcium channels in membrane preparations from the longitudinal smooth muscle of rabbit ileum bound [3H]PN 200-110 with KD = 0.42 nM and Bmax = 265 fmol/mg. Calcium channels were labelled with [3H]PN 200-110 and solubilized with digitonin. The detergent-solubilized calcium channel had a sedimentation coefficient of 20.9 S in close agreement with the value of 20 S determined for the skeletal muscle calcium channel. Antibodies against the alpha-subunits of the skeletal muscle calcium channel specifically precipitated the calcium channel from smooth muscle. Our results suggest that the calcium channel from smooth muscle has a similar size and homologous alpha-subunits to those of the purified skeletal muscle calcium channel.
D000818:Animals; D000937:Antigen-Antibody Reactions; D002118:Calcium / Q000378:metabolism*; D002499:Centrifugation, Density Gradient; D055598:Chemical Phenomena; D002621:Chemistry; D004594:Electrophysiology; D007082:Ileum / Q000378:metabolism*; D007106:Immune Sera / Q000276:immunology; D007473:Ion Channels / Q000276:immunology / Q000378:metabolism / Q000502:physiology; D017275:Isradipine; D009130:Muscle, Smooth / Q000378:metabolism*; D009132:Muscles / Q000378:metabolism*; D010069:Oxadiazoles / Q000378:metabolism; D011817:Rabbits; D011955:Receptors, Drug / Q000378:metabolism; D012995:Solubility
D007106:Immune Sera; D007473:Ion Channels; D010069:Oxadiazoles; D011955:Receptors, Drug; D002118:Calcium; D017275:Isradipine