title: Four conductance levels of cloned cardiac L-type Ca2+ channel alpha1 and alpha1/beta subunits.
abstract: Formation of single channel subconductance is one of the unique characteristics of the L-type Ca2+ channel. Although alpha1 subunit exhibits a primary function of the channel, it remains uncertain whether alpha1 subunit alone is able to produce subconductance. We tested this by studying single channel currents of cloned cardiac alpha1 subunit expressed in Chinese hamster fibroblast cells, with/without coexpression of cardiac beta subunit. The alpha1 subunit exhibited four distinct levels of conductance (22.7, 14.3, 6.2 and 3.2 pS). Coexpression of beta subunit significantly increased the number of openings in all four levels of conductance without changing the conductance values.
authors.affiliation: Department of Physiology, Oita Medical University, Hasama, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Gondo
authors.forename: K
authors.initials: K
authors.lastname: Ono
authors.forename: K
authors.initials: K
authors.lastname: Mannen
authors.forename: A
authors.initials: A
authors.lastname: Yatani
authors.forename: S A
authors.initials: SA
authors.lastname: Green
authors.forename: M
authors.initials: M
authors.lastname: Arita
mesh_terms: D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology; D000818:Animals; D001665:Binding Sites; D002120:Calcium Channel Agonists / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D002460:Cell Line; D006224:Cricetinae; D003412:Cricetulus; D004553:Electric Conductivity; D004594:Electrophysiology; D015640:Ion Channel Gating / Q000187:drug effects / Q000502:physiology; D011817:Rabbits; D012964:Sodium / Q000378:metabolism; D013329:Structure-Activity Relationship
chemical_list: D002120:Calcium Channel Agonists; D015220:Calcium Channels; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D012964:Sodium