Sensitivity of the sodium and potassium channels of Myxicola giant axons to changes in external pH

Autor:	C L Schauf, F A Davis
Rok vydání:	1976
Předmět:	Membrane potential Physiology Chemistry Sodium Potassium Inorganic chemistry chemistry.chemical_element Polychaeta Depolarization Articles Axons Potassium channel Membrane Potentials Kinetics medicine.anatomical_structure Reaction rate constant medicine Biophysics Animals Surface charge Axon
Zdroj:	The Journal of General Physiology
ISSN:	1540-7748 0022-1295
DOI:	10.1085/jgp.67.2.185
Popis:	Myxicola giant axons were studied using standard voltage-clamp techniques in solutions whose pH values ranged from 3.9 to 10.2. Buffer concentrations of 50 mM or greater were necessary to demonstrate the full effect of pH. In acidic solutions the axon underwent a variable depolarization, and both the sodium and potassium conductances were reversibly depressed with approximate pKa's of 4.8 and 4.4, respectively. The voltage dependence of GNa was only slightly altered by acidic conditions, whereas there occurred large shifts in GK along the voltage axis consistent with a substantial decrease in net negative surface charge in the vicinity of the K+ channels. The sodium and potassium activation rate constants were decreased by acidic conditions, but the results could not be described as a simple translation along the voltage axis.
Databáze:	OpenAIRE
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