title: An endogenous acid-sensitive K+ channel expressed in COS-7 cells.
abstract: COS-7 cells originally isolated from monkey kidney and used in many transfection studies were found to express a background K+ channel and therefore, its biophysical and pharmacological properties were examined. In cell-attached patches, a 32-pS K+ channel with a linear current-voltage relationship could be recorded. The open probability was highly voltage-dependent, with greater channel activity at depolarized potentials. The channel was markedly sensitive to changes in extracellular pH (pH(o)), showing a 70+/-10% inhibition by changing the pH(o) from 7.3 to 6.3. Arachidonic acid (5 microM) augmented channel activity 12-fold. Applying negative pressure (-40 mmHg) to the membrane patch also increased channel activity by 4-fold. These results show that COS-7 cells express a K+ channel with unique properties that must be considered when using these cells as transfection system.
authors.affiliation: Department of Physiology, College of Medicine and Institute of Health Science, Gyeongsang National University, Jinju 660-751, Republic of Korea.
authors.forename: Dawon
authors.initials: D
authors.lastname: Kang
authors.forename: Jun-Ho
authors.initials: JH
authors.lastname: La
authors.forename: Eun-Jin
authors.initials: EJ
authors.lastname: Kim
authors.forename: Jae-Yong
authors.initials: JY
authors.lastname: Park
authors.forename: Seong-Geun
authors.initials: SG
authors.lastname: Hong
authors.forename: Jaehee
authors.initials: J
authors.lastname: Han
mesh_terms: D000818:Animals; D016718:Arachidonic Acid / Q000494:pharmacology; D019556:COS Cells; D002531:Cerebellum / Q000502:physiology; D002522:Chlorocebus aethiops; D006863:Hydrogen-Ion Concentration; D009474:Neurons / Q000502:physiology; D015221:Potassium Channels / Q000096:biosynthesis* / Q000187:drug effects / Q000502:physiology; D011312:Pressure; D051381:Rats; D014162:Transfection / Q000379:methods
chemical_list: C503434:Kcnk4 protein, rat; D015221:Potassium Channels; D016718:Arachidonic Acid