scholarly journals Studying properties of neurotransmitter receptors by non-stationary noise analysis of spontaneous synaptic currents

2006 ◽  
Vol 574 (3) ◽  
pp. 751-785 ◽  
Author(s):  
Espen Hartveit ◽  
Margaret Lin Veruki
Keyword(s):  
Noise Analysis ◽  
Neurotransmitter Receptors ◽  
Synaptic Currents ◽  
Stationary Noise

scholarly journals Comparison of excitatory currents activated by different transmitters on crustacean muscle. I. Acetylcholine-activated channels.

1983 ◽  
Vol 81 (4) ◽  
pp. 547-569 ◽  
Author(s):  
C Lingle ◽  
A Auerbach
Keyword(s):  
Membrane Potential ◽  
Time Course ◽  
Voltage Dependence ◽  
Single Channel ◽  
Noise Analysis ◽  
Synaptic Currents ◽  
Cancer Borealis ◽  
Open Time ◽  
Conductance Increase ◽  
Channel Open Time

The properties of acetylcholine-activated excitatory currents on the gm1 muscle of three marine decapod crustaceans, the spiny lobsters Panulirus argus and interruptus, and the crab Cancer borealis, were examined using either noise analysis, analysis of synaptic current decays, or analysis of the voltage dependence of ionophoretically activated cholinergic conductance increases. The apparent mean channel open time (tau n) obtained from noise analysis at -80 mV and 12 degrees C was approximately 13 ms; tau n was prolonged e-fold for about every 100-mV hyperpolarization in membrane potential; tau n was prolonged e-fold for every 10 degrees C decrease in temperature. Gamma, the single-channel conductance, at 12 degrees C was approximately 18 pS and was not affected by voltage; gamma was increased approximately 2.5-fold for every 10 degrees C increase in temperature. Synaptic currents decayed with a single exponential time course, and at -80 mV and 12 degrees C, the time constant of decay of synaptic currents, tau ejc, was approximately 14-15 ms and was prolonged e-fold about every 140-mV hyperpolarization; tau ejc was prolonged about e-fold for every 10 degrees C decrease in temperature. The voltage dependence of the amplitude of steady-state cholinergic currents suggests that the total conductance increase produced by cholinergic agonists is increased with hyperpolarization. Compared with glutamate channels found on similar decapod muscles (see the following article), the acetylcholine channels stay open longer, conduct ions more slowly, and are more sensitive to changes in the membrane potential.

scholarly journals Non-Stationary Noise Analysis of Magnetic Sensors using Allan Variance

2017 ◽  
Vol 131 (4) ◽  
pp. 1126-1128 ◽  
Author(s):  
K. Draganová ◽  
V. Moucha ◽  
T. Volčko ◽  
K. Semrád
Keyword(s):  
Noise Analysis ◽  
Allan Variance ◽  
Magnetic Sensors ◽  
Stationary Noise

Kinetic Modulation of HERG  Potassium Channels by the Volatile Anesthetic Halothane

2002 ◽  
Vol 97 (4) ◽  
pp. 921-930 ◽  
Author(s):  
Jichang Li ◽  
Ana M. Correa
Keyword(s):  
Single Channel ◽  
Noise Analysis ◽  
Delayed Rectifier ◽  
Kinetic Properties ◽  
Dependent Manner ◽  
General Anesthetics ◽  
Open Probability ◽  
Concentration Dependent Manner ◽  
Stationary Noise ◽  
Herg Channels

Background (human ether-a-gogo related gene) encodes the cardiac rapidly activating delayed rectifier potassium currents (I(kr)), which play an important role in cardiac action potential repolarization. General anesthetics, like halothane, can prolong Q-T interval, suggesting that they act on myocellular repolarization, possibly involving HERG channels. Evidence for direct modulation of HERG channels by halothane is still lacking. To gain insight on HERG channel modulation by halothane the authors recorded macroscopic currents expressed in Xenopus oocytes and conducted non-stationary noise analysis to evaluate single channel parameters modified by the anesthetic. Methods Macroscopic currents were recorded in 120 mM K(+) internal-5 mM K(+) external solutions with the cut open oocyte technique. Macropatch recordings for non-stationary noise analysis of HERG tail currents were made in symmetrical 120 mM K(+) solutions. Pulse protocols designed for HERG current recording were elicited from a holding potential of -80 mV. Halothane was delivered via gravity-fed perfusion. Results Halothane (0.7%, 1.5%, and 3%) decreased macroscopic currents in a concentration-dependent manner (average reduction by 14%, 22%, and 35% in the range of -40 mV to 40 mV) irrespective of potential. HERG currents had slower activation and accelerated deactivation and inactivation. Non-stationary noise analysis revealed that halothane, 1.5%, decreased channel P(o) by 27%, whereas single-channel current amplitudes and number of channels in the patch remained unchanged. Conclusions Halothane inhibits HERG currents expressed in oocytes in a concentration-dependent manner. It slowed down activation and accelerated deactivation and inactivation of HERG channels. The authors' results demonstrate that halothane decreased HERG currents by modulating kinetic properties of HERG channels, decreasing their open probability. Partial block of I(kr) currents could contribute to delayed myocellular repolarization and altered cardiac electrophysiology.

scholarly journals Single-channel properties of a volume-sensitive anion conductance. Current activation occurs by abrupt switching of closed channels to an open state.

1995 ◽  
Vol 105 (5) ◽  
pp. 643-660 ◽  
Author(s):  
P S Jackson ◽  
K Strange
Keyword(s):  
Single Channel ◽  
Noise Analysis ◽  
Anion Channel ◽  
Single Channels ◽  
Channel Measurements ◽  
Anion Channels ◽  
Open Probability ◽  
Stationary Noise ◽  
Unitary Conductance ◽  
Current Activation

Swelling-induced loss of organic osmolytes from cells is mediated by an outwardly rectified, volume-sensitive anion channel termed VSOAC (Volume-Sensitive Organic osmolyte/Anion Channel). Similar swelling-activated anion channels have been described in numerous cell types. The unitary conductance and gating kinetics of VSOAC have been uncertain, however. Stationary noise analysis and single-channel measurements have produced estimates for the unitary conductance of swelling-activated, outwardly rectified anion channels that vary by > 15-fold. We used a combination of stationary and nonstationary noise analyses and single-channel measurements to estimate the unitary properties of VSOAC. Current noise was analyzed initially by assuming that graded changes in macroscopic current were due to graded changes in channel open probability. Stationary noise analysis predicts that the unitary conductance of VSOAC is approximately 1 pS at 0 mV. In sharp contrast, nonstationary noise analysis demonstrates that VSOAC is a 40-50 pS channel at +120 mV (approximately 15 pS at 0 mV). Measurement of single-channel events in whole-cell currents and outside-out membrane patches confirmed the nonstationary noise analysis results. The discrepancy between stationary and nonstationary noise analyses and single-channel measurements indicates that swelling-induced current activation is not mediated by a graded increase in channel open probability as assumed initially. Instead, activation of VSOAC appears to involve an abrupt switching of single channels from an OFF state, where channel open probability is zero, to an ON state, where open probability is near unity.

Reply: Noise analysis for digit slicing FFT

1992 ◽  
Vol 139 (4) ◽  
pp. 278
Author(s):  
Z.A.M. Sharrif ◽  
M. Othman ◽  
T.S. Theong
Keyword(s):  
Noise Analysis

Noise Analysis of Direct Sampling Mixers

2014 ◽  
Vol 134 (8) ◽  
pp. 1002-1009 ◽  
Author(s):  
Yohei Morishita ◽  
Noriaki Saito ◽  
Koji Takinami ◽  
Kiyomichi Araki
Keyword(s):  
Noise Analysis ◽  
Direct Sampling
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