... Periodic voltage — Harmonic voltage 45 -- The power of alternating current 47 -- Measuring A. ... ... C. voltage and current 48 -- 2. Nonharmonic voltage 49 -- Aperiodic voltage. ... ... 119 -- The triode limiter using the anode current cut-off 120 -- A limiter using shift of cathode current ... ... C. current on the isolated nerve fibre 446 -- B. ... ... Correlation with other events 628 -- 3. Distribution of inter-spike intervals 632 -- H. ...
3. rev. ed. 824 s. : il.
The current density (J) is a parameter routinely used to characterize individual ionic membrane currents. Its evaluation is based on the presumption that the magnitude of whole-cell ionic membrane current (I) is directly proportional to the cell membrane capacitance (C), i.e. I positively and strongly correlates with C and the regression line describing I-C relation intersects the y-axis close to the origin of coordinates. We aimed to prove the presumption in several examples and find whether the conversion of I to J could be always beneficial. I-C relation was analysed in several potassium currents, measured in rat atrial myocytes (in inward rectifier currents, IK1, and both the constitutively active and acetylcholine-induced components of acetylcholine-sensitive current, IK(Ach)CONST and IK(Ach)ACH), and in rat ventricular myocytes (transient outward current Ito). I-C correlation was estimated by the Pearson coefficient (r). A coefficient (k) was newly suggested describing deviation of the regression intercept from zero in currents with considerable r value. Based on mathematical simulations, I was satisfactorily proportional to C when r ≥ 0.6 and k ≤ 0.2 which was fulfilled in IK1 and IK(Ach)ACH (r = 0.84, k = 0.20, and r = 0.61, k = 0.06, respectively). I-C correlation was significantly positive, but weak in IK(Ach)CONST (r = 0.42), and virtually missing in Ito (r = 0.04). The impaired I-C proportionality in IK(Ach)CONST and Ito likely reflects heterogeneity of the channel expression. We conclude that the conversion of I to J should be avoided when I-C proportionality is absent. Otherwise, serious misinterpretation of data may arise.
- MeSH
- Acetylcholine chemistry MeSH
- Cell Membrane physiology MeSH
- Electric Capacitance MeSH
- Electrophysiology MeSH
- Genotype MeSH
- Ions MeSH
- Myocytes, Cardiac drug effects MeSH
- Rats MeSH
- Membrane Potentials drug effects MeSH
- Myocardium MeSH
- Rats, Wistar MeSH
- Heart Atria pathology MeSH
- Muscle Cells cytology MeSH
- Models, Theoretical MeSH
- Animals MeSH
- Check Tag
- Rats MeSH
- Male MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
... -- An Equivalent Circuit Model of the Membrane Includes Batteries, Conductors, a Capacitor, and a Current ... ... of Signal Conduction 143 -- Large Axons Are More Easily Excited Than Small Axons by Extracellular Current ... ... the Voltage Clamp 151 -- Voltage-Gated Sodium and Potassium Conductances Are Calculated From Their Currents ... ... Ion Channels at the End-Plate 190 -- The Synaptic Potential at the End-Plate Is Produced by Ionic Current ... ... Martin -- Sensory Systems Mediate Four Attributes of a Stimulus That Can Be Correlated Quantitatively ...
4th ed. xxxiii, 1414 s. : il., tab., grafy ; 30 cm
- MeSH
- Behavior MeSH
- Molecular Biology MeSH
- Nervous System Diseases MeSH
- Nervous System MeSH
- Neurochemistry MeSH
- Neurophysiology MeSH
- Neurons MeSH
- Neurosciences MeSH
- Publication type
- Monograph MeSH
- Conspectus
- Fyziologie člověka a srovnávací fyziologie
- NML Fields
- neurovědy
- biologie
