ISSN:
1432-1424
Keywords:
rat ventricle
;
isolated single cell
;
volrage-clamp
;
internal perfusion
;
Na current
;
extracellular pH
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Summary Effects of extracellular pH on the sodium current (I Na) of single rat ventricular cells were examined under conditions of voltage clamp and internal perfusion. In this way, pH i was controlled while pH o was changed. The combined suction pipette-microelectrode method was used. The suction pipette passed current and perfused the cell's interior; the microelectrode measured membrane potential. Increasing extracellular H+ depressedI Na and slowed inactivation. The current-voltage curves forI Na and Slowed inactivation. The current-voltage curves forI Na were shifted to positive and negative potentials at low and high pH o , respectively. Similar potential shifts were observed in both the conductance voltage curve and the steadystate inactivation voltage curve (h ∞). Conduction was also depressed at low pH o . The shifts were probably due to surface charge effects, while the impaired conduction was probably due to protonation of a site in the Na channel.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01869203
