Emergence of a chloride permeability after internal perfusion with calcium in squid giant axons.
In the resting condition, the membrane of the squid giant axon is highly permeable to K+, and shows large changes in membrane potential following an increase in external or internal K-concentration. When 3-5 mM Ca2+ was applied internally for 3 min, the membrane became highly permeable to Cl- as compared to K+. The permeability ratio PCl/PK was about 0.77 in control experiments, rising to a ratio of 5.5 after Ca2+ administration. The membrane conductance also increased 6-fold over controls. The permeability ratios for other anions, Cl-, F-, methanesulfate (MS), and HEPES (PCl, PF, PMS, and PHEPES) were 1.00, 0.54, 0.23, and 0.13, respectively.
Yamagishi
S
S
Department of Cell Physiology, National Institute for Physiological Sciences, Okazaki, Japan.
Tsutsui
I
I
Furuya
K
K
D000818:Animals; D001369:Axons / Q000502:physiology*; D002118:Calcium / Q000378:metabolism*; D002586:Cesium / Q000494:pharmacology; D002712:Chlorides / Q000378:metabolism*; D049832:Decapodiformes; D006531:HEPES / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects*; D013431:Sulfates / Q000494:pharmacology
D002712:Chlorides; D013431:Sulfates; D002586:Cesium; D006531:HEPES; D002118:Calcium