PT  - JOURNAL ARTICLE
AU  - Emmanuel Bourinet
AU  - Gerald W. Zamponi
AU  - Anthony Stea
AU  - Tuck W. Soong
AU  - Bertram A. Lewis
AU  - Lisa P. Jones
AU  - David T. Yue
AU  - Terry P. Snutch
TI  - The α<sub>1E</sub> Calcium Channel Exhibits Permeation Properties Similar to Low-Voltage-Activated Calcium Channels
AID  - 10.1523/JNEUROSCI.16-16-04983.1996
DP  - 1996 Aug 15
TA  - The Journal of Neuroscience
PG  - 4983--4993
VI  - 16
IP  - 16
4099  - http://www.jneurosci.org/content/16/16/4983.short
4100  - http://www.jneurosci.org/content/16/16/4983.full
SO  - J. Neurosci.1996 Aug 15; 16
AB  - The physiological and pharmacological properties of the α1E calcium (Ca) channel subtype do not exactly match any of the established categories described for native neuronal Ca currents. Many of the key diagnostic features used to assign cloned Ca channels to their native counterparts, however, are dependent on a number of factors, including cellular environment, β subunit coexpression, and modulation by second messengers and G-proteins. Here, by examining the intrinsic pore characteristics of a family of transiently expressed neuronal Ca channels, we demonstrate that the permeation properties of α1E closely resemble those described for a subset of low-threshold Ca channels. The α1A (P-/Q-type), α1B(N-type), and α1C (L-type) high-threshold Ca channels all exhibit larger whole-cell currents with barium (Ba) as the charge carrier as compared with Ca or strontium (Sr). In contrast, macroscopic α1E currents are largest in Sr, followed by Ca and then Ba. The unique permeation properties of α1E are maintained at the single-channel level, are independent of the nature of the expression system, and are not affected by coexpression of α2 and β subunits. Overall, the permeation characteristics of α1E are distinct from those described for R-type currents and share some similarities with native low-threshold Ca channels.