Ionic channels classification

W Michael King 74244.2040 at compuserve.com
Tue Jul 25 14:19:44 EST 1995


In article <3ug92d$1sf at mojo.eng.umd.edu>, didier at src.umd.edu says...
>
>
>frank.le_foll at univ-rouen.fr (Frank Le Foll) writes:
>>
>> I'm looking for the origin of the 'A' in the IA nammed potassium channel.
>>
>
>On page 117, Hille says:
>"Some encoding membranes have an additional K-channel that activates
>transiently [...]. Current in this channel has been variously called 
>A-current (IA), fast transient K current, transient outward current 
>(Ito), and rapidly inactivating K current."
>
>Connor and Stevens coined the term A-current, hence the answer might lie 
>in the original article. But Hille's comments seem to point to the fact
>that there's no logical explanation for the 'A'! 
>
>Connor J.A. and Stevens C.F., Voltage clamp studies of a transient outward
>membrane current in gastropod neural somata, J Physiol (Lond) 213 (1971)
>pp. 31-53.
>
>
>                                                Didier
>

Didier got the original discovery right, and Bertil Hille's book is an
excellent reference for ion channel classification, but the notion that there
is no logical explanation for the A current is inaccurate. This channel has
since been described in several phyla; the gene(s) have been identified, and 
the physiology has been explored in many many preps since 1971!
Cheers, W. Michael King




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