title: Investigations into the correlation properties of membrane electroporation-induced inward currents: prediction of pore formation.
abstract: Membrane electroporation (MEP) induces a drastic change in membrane conductance and permeability. However, the underlying mechanisms by which MEP-induced currents (I(MEP)) are generated or resealed remain unclear. In this study, we investigated how the fluctuations of I(MEP) might be elicited in different types of cells, including pituitary GH(3) cells, NG108-15 neuronal cells, and RAW 264.7 macrophages. We applied the detrended fluctuation analysis (DFA) to analyze the current signals in response to large hyperpolarizations. The DFA exponents from the current signals at 10 s preceding the start of the initial I(MEP) (I(Pre)) in GH(3) cells exhibited two components (short time lag [α(1)] and long time lag [α(2)]) with a crossover threshold of about 7 ms. The α(1) value was 0.46 ± 0.04 (n = 7), whereas the α(2) value with 0.62 ± 0.05 (n = 7) indicated the presence of long-term correlations of current signals. However, during maximal I(MEP), the slope of double logarithmic plot was linear and estimated to be 0.99 ± 0.02 (n = 8) with no clear crossover. Upon changes in membrane polarization, neither short- nor long-range correlation was altered. Chloroquine (CQ), a lysosomotropic agent, decreased the I(MEP) amplitude with an IC(50) value of 46 μM; however, it had no effects on the scaling exponents of I(Pre) or I(MEP). Although CQ or membrane polarization altered the amplitudes of I(MEP), no changes in correlation properties of this current were detected. The scaling exponents derived from I(Pre) exhibit long-range correlations in these different types of cells, indicating there is a correlated character of the electropore dynamics that may be allowed to predict the MEP process.
authors.affiliation: Department of Physiology, National Cheng Kung University Medical College, Tainan City, Taiwan. snwu@mail.ncku.edu.tw
authors.forename: Sheng-Nan
authors.initials: SN
authors.lastname: Wu
authors.forename: Chia-Chen
authors.initials: CC
authors.lastname: Yeh
authors.forename: Pei-Yu
authors.initials: PY
authors.lastname: Wu
authors.forename: Hsien-Ching
authors.initials: HC
authors.lastname: Huang
authors.forename: Mei-Ling
authors.initials: ML
authors.lastname: Tsai
mesh_terms: D000818:Animals; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects / Q000502:physiology*; D002463:Cell Membrane Permeability / Q000187:drug effects; D002738:Chloroquine / Q000494:pharmacology; D018274:Electroporation; D015640:Ion Channel Gating; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D018408:Patch-Clamp Techniques; D051381:Rats
chemical_list: D002738:Chloroquine