Complimentary DNA clones encoding the alpha1C and beta2a subunits of @entity840 cardiac L-type @entity141 channels were isolated using the PCR method. The open reading frame encoded 2,169 @entity1522 for the alpha1C and 597 @entity1522 for the beta2a subunit. The proteins showed 94.2 and 94.8%, respectively, identity to the respective subunit of the @entity95 protein. The message size of the @entity840 alpha1C and beta2a subunits was 8.0 and 3.5/4.0 kb, respectively. RT-PCR analysis revealed that the alpha1C subunit is expressed exclusively in the heart, while the beta2a subunit is expressed in the heart, cerebellum, whole brain, and stomach. The alpha1C and beta2a subunits are transiently expressed in BHK (baby hamster kidney) cells, and the channel currents were studied using the whole-cell patch clamp technique in medium containing 30 mM @entity8594 . In cells expressing alpha1C alone, the @entity8594 current was activated at -30 mV and more positive potentials and peaked at about 10 mV. The co-expression of beta2a with alpha1C did not affect the voltage-dependence of the current, but increased the peak current and accelerated current decay. In cells transfected with @entity840 alpha1C and @entity95 beta1+alpha2/delta, a @entity8594 current comparable to those in native myocytes was observed. The @entity8594 current can be blocked completely by @entity594 and is enhanced 3-fold by @entity9898 . On the other hand, neither @entity1928 nor @entity18398 affects the @entity8594 current, suggesting that @entity268 -mediated modulation is not easily reproduced in transfected cells, unlike that seen in native cardiac myocytes.

Cloning and expression of the @entity141 channel alpha1C and beta2a subunits from XXXX heart.

@entity268 :: ('CHEBI:17489', 'Chemical') :: ['cAMP'] @entity1522 :: ('CHEBI:33709', 'Chemical') :: ['amino acids'] @entity840 :: ('10141', 'Species') :: ['guinea-pig', 'guinea pig'] @entity95 :: ('9986', 'Species') :: ['rabbit'] @entity8594 :: ('MESH:C080430', 'Chemical') :: ['Ba2+'] @entity594 :: ('MESH:D009543', 'Chemical') :: ['nifedipine'] @entity141 :: ('CHEBI:29108', 'Chemical') :: ['Ca2+'] @entity18398 :: ('MESH:D019319', 'Chemical') :: ['okadaic acid'] @entity9898 :: ('MESH:D001498', 'Chemical') :: ['Bay K 8644'] @entity1928 :: ('MESH:D005576', 'Chemical') :: ['forskolin']
@entity840 :: (10141,Species) :: ['guinea pig']
