Journal article
A β-subunit normalizes the electrophysiological properties of a cloned N-type CA2+ channel α1-subunit
Neuropharmacology, Vol.32(11), pp.1103-1116
11/1993
DOI: 10.1016/0028-3908(93)90005-N
Abstract
The electrophysiological and pharmacological properties of a cloned rat brain N-type Ca2+ channel were determined by transient expression in Xenopus oocytes. Expression of the class B Ca2+ channel α1 subunit, rbB-I, resulted in a high voltage-threshold current that activated slowly and showed little inactivation over 800 msec. Characteristic of N-type currents, the rbB-I current was completely blocked by ω-conotoxin GVIA and was insensitive to nifedipine and Bay K8644. The modulatory effects on the rbB-I current by cloned rat brain Ca2+ channel α2 and β1b subunits were also examined. Coexpression of rbB-I with the β1b subunit caused significant changes in the properties of the rbB-I current making it more similar to N-type currents in neurons. These included: (1) an increase in the whole-cell current, (2) an increased rate of activation, (3) a shift of the voltage-dependence of inactivation to hyperpolarized potentials and (4) a pronounced inactivation of the current over 800 msec. Coexpression with the rat brain α2 subunit had no significant effect on the rbB-I current alone but appeared to potentiate the rbB-I + β1b whole cell current. The results show that coexpression with the brain β1b subunit normalizes the rbB-I N-type current, and suggests the possibility that differences in subunit composition may contribute to the heterogeneous properties described for N-type channels in neurons.
Details
- Title: Subtitle
- A β-subunit normalizes the electrophysiological properties of a cloned N-type CA2+ channel α1-subunit
- Creators
- Anthony SteaStefan J DubelMarlon Pragnell - University of IowaJohn P LeonardKevin P Campbell - University of Iowa, Molecular Physiology and BiophysicsTerry P Snutch
- Resource Type
- Journal article
- Publication Details
- Neuropharmacology, Vol.32(11), pp.1103-1116
- DOI
- 10.1016/0028-3908(93)90005-N
- ISSN
- 0028-3908
- eISSN
- 1873-7064
- Language
- English
- Date published
- 11/1993
- Academic Unit
- Molecular Physiology and Biophysics; Neurology; Iowa Neuroscience Institute
- Record Identifier
- 9984068250802771
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