Potassium channels from normal and denervated mouse skeletal muscle fibers.
The properties of singles K+ channels in normal and denervated muscles were compared using the "patch-clamp" technique. Single channels were recorded from vesicles obtained by stretching bundles of normal and denervated extensor digitorium longus (EDL) muscles. The most frequently observed channel in normal muscles was a high conductance (266 pS) Ca++ activated K+ channel. Although channel density, as estimated by patch recording, showed a significant decrease in denervated muscles, no differences were found in conductance and gating properties. Another voltage-dependent K+ channel (81 pS) was only recorded from normal muscles, but never from denervated ones. In addition, a 35 pS conductance was recorded from both normal and denervated fibers. This channel displayed neither voltage dependence nor sensitivity to tetraethylammonium (TEA). In contrast, another TEA-insensitive (16 pS) channel was recorded only from denervated muscles. We conclude that denervation induces significant changes in the distribution and expression of K+ channels in mammalian skeletal muscles.
Escobar
A L
AL
Instituto de Biología Celular, Facultad de Medicina, Universidad de Buenos Aires, Argentina.
Schinder
A F
AF
Biali
F I
FI
Nicola
L C
LC
Uchitel
O D
OD
D000818:Animals; D002118:Calcium / Q000502:physiology; D008297:Male; D008564:Membrane Potentials / Q000502:physiology; D051379:Mice; D009121:Muscle Denervation / Q000009:adverse effects*; D009132:Muscles / Q000502:physiology / Q000503:physiopathology*; D015221:Potassium Channels / Q000187:drug effects / Q000473:pathology / Q000502:physiology*; D019789:Tetraethylammonium; D013757:Tetraethylammonium Compounds / Q000494:pharmacology
D015221:Potassium Channels; D013757:Tetraethylammonium Compounds; D019789:Tetraethylammonium; D002118:Calcium