ISSN:
1432-1424
Keywords:
Chara
;
calcium
;
protons
;
potassium
;
electrogenic pump
;
conductance
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Summary Removal of Ca2+ from the medium results in depolarization of theChara internodal cell and an increase in membrane conductance (G m). The increase in conductance is associated with an increase in K+ conductance, as judged by Ca2+ effects on the K+ dependence of clamp current. The voltage dependence ofG m is also affected by Ca2+, as is the time course of the response of clamp current to a step change in voltage. Mg2+ restores the low conductance and the fast response to a voltage change, but not hyperpolarization at neutral pH, suggesting that there is an additional, independent effect on the electrogenic pump. The membrane does not show the normal ability to increase proton conductance at high pH in the absence of Ca2+; this is also restored by Mg2+ as well as by Ca2+.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01868810
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