ISSN:
1432-1017
Keywords:
K+-channels
;
patch-clamp
;
heart
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Physics
Notes:
Abstract Studies on single K+-channel currents recorded from isolated rat heart muscle cells, in which early repolarization is known to be exceptionally fast, are reported here. A K+-channel which is blocked by TEA (tetraethylammonium) from the inside only has been found. The total open time of the channel, measured in steady-state after activation, indicated outward rectifying properties. The single channel conductance increases with depolarization from 25 pS at-70 mV to 75 pS at+70 mV. Selectivity of the channel has also been measured and it was found that only Rb+ and K+ can permeate the channel, whereas the permeability (P) for Li+, Na+, Cl-, Mg2+, and Ca2+ is less than 0.05 times $${\text{P}}_{{\text{K}}^{\text{ + }} } $$ . Ba2+ and Cs+ block the channel activity. These results clearly demonstrate the existence of K+-selective outward rectifying conductance pathways in rat ventricular myocytes.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00262003
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