Physiology and Pharmacology
Physiol Pharmacol
Medical Sciences
http://ppj.phypha.ir
32
journal32
24765236
24765244
10.61186/phypha
(previous ISSN: 17350581)
en
jalali
1390
1
1
gregorian
2011
4
1
15
1
online
1
fulltext
en
Evidences on the existence of a new potassium channel in the rough endoplasmic reticulum (RER) of rat hepatocytes
Cell, Stem Cell and Cancer
Cell, Stem Cell and Cancer
Experimental research article
Experimental research article
Introduction: we have recently reported the presence of two potassium currents with 598 and 368 pS conductance
in the rough endoplasmic reticulum (RER) membrane. The 598 pS channel was voltage dependent and ATP sensitive.
However, the 368 pS channel was rarely observed and its identity remained obscure. Since cationic channels in
intracellular organelles such as mitochondria and RER play important roles in intracellular signaling and cellular
protection, studying their biophysical and pharmacological properties is important.
Methods: we used channel incorporation into bilayer lipid membrane method. L-α-Phosphatidylcholine (PC), a
membrane lipid, was extracted from fresh egg yolk. Bilayer lipid membrane was formed in a 150 μm diameter hole.
Rough endoplasmic reticulum vesicles were obtained from liver after homogenization and several centrifugations. All
recordings were filtered at 1 kHz and stored at a sampling rate of 10 kHz for offline analysis by PClamp9. Statistical
analysis was performed based on Markov noise free single channel analysis.
Results: A 364 pS potassium channel was identified which was voltage independent in +50 to -50 mV voltages. In
all voltages, open probability (Po) was over 0.9. Nonspecific inhibitor of K+ channels, 4-aminopyridine (4-AP, 20 mM),
inhibited the channel activity. However, intracellular nucleotide like ATP had no effect on channel gating.
Conclusion: We observed a new potassium channel with 346 pS conductance in RER membrane that unlike the 598
pS K channel was not ATP sensitive. This channel may play an important role in Ca2+ homeostasis and cell protection.
Key words: BLM, endoplasmic reticulum, potassium channel
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http://ppj.phypha.ir/browse.php?a_code=A-10-123-41&slc_lang=en&sid=1
Sajjad
Salari
3200319475328460010114
3200319475328460010114
No
Shahid Beheshti university of medical science
Afsaneh Afsaneh
Eliassi
afeliassi@sbmu.ac.ir
3200319475328460010115
3200319475328460010115
Yes
Shahid Beheshti university of medical science
Reza
Saghiri
3200319475328460010116
3200319475328460010116
No
Pasteur Institute of Iran