Membrane Conductance Changes Associated with the Response of Motion Sensitive Insect Visual Neurons

Abstract Intracellular recordings and impedance measurements from directionally-selective visual interneurons of the lobula plate of flies show that during motion, transmembrane conductance increases during both depolarizing responses to preferred directions and hyperpolarizing responses to anti-preferred directions. This provides direct evidence that these interneurons are postsynaptic to two separate populations of excitatory and inhibitory input elements.

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Intracellular recordings from different types of medullary respiratory neurons of the cat

Journal of Neurophysiology ◽

10.1152/jn.1975.38.5.1162 ◽

1975 ◽

Vol 38 (5) ◽

pp. 1162-1171 ◽

Cited By ~ 56

Author(s):

D. W. Richter ◽

F. Heyde ◽

M. Gabriel

Keyword(s):

Functional Organization ◽

Silent Period ◽

Membrane Conductance ◽

Rhythmic Activity ◽

Excitatory Input ◽

Respiratory Neurons ◽

Inhibitory Input ◽

Different Types ◽

Conductance Changes ◽

Almost All

Respiratory neurons were recorded intracellularly within the lateral region of the lower brain stem of vagotomized and artificially ventilated cats. Bulbospinal, vagal, and antidromically nonresponsive types of neurons were distinguished by means of vagal and intraspinal stimulation. Almost all types of neurons discharged a burst of action potentials during one of the two phases of the central respiratory cycle, as indicated by phrenic nerve activity. The discharge pattern of the different types of neurons were described. The origin of the spntaneous changes of the membrane potential was investigated by measurements of the reversal potentials and membrane conductance changes. The results reveal that both inspiratory and expiratory types of neurons receive an excitatory input during their discharge period, and a reciprocal inhibitory input during their silent period. In addition, one type of neuron was described which receives inhibitory inputs during both inspiration and expiration. Recurrent inhibition, as indicated by hyperpolarizing postsynaptic potentials and membrane conductance changes following the antidromic action potential seems to exist only within the network of the vagal neurons. Suggestions are made about the functional organization of the neuronal network of the medullary respiratory system and the mechanism generating its rhythmic activity.

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Location of membrane conductance changes by analysis of the input impedance of neurons. II. Implementation

Journal of Neurophysiology ◽

10.1152/jn.1985.54.6.1594 ◽

1985 ◽

Vol 54 (6) ◽

pp. 1594-1606 ◽

Cited By ~ 7

Author(s):

S. E. Fox ◽

C. Y. Chan

Keyword(s):

Mathematical Modeling ◽

Input Impedance ◽

Membrane Conductance ◽

Wave Impedance ◽

Sine Wave ◽

Single Neurons ◽

Impedance Measurements ◽

Conductance Changes ◽

Laminated Structures ◽

Axial Resistance

Mathematical modeling has shown that it should be possible to determine the electrotonic location of membrane conductance changes in single neurons by analysis of the associated changes in the magnitude of the alternating-current (AC) input impedance. The form of the plot of change in the magnitude of the input impedance as a function of frequency (delta [Zn(f)]) should differ for changes in membrane conductance located at different electrotonic distances from the recording/current-injection site. Due to the axial resistance and the membrane capacitance, the higher frequencies are attenuated with distance to a greater degree than are the lower frequencies. Thus delta [Zn(f)] should drop to zero more rapidly with increasing frequency for distal than for proximal conductance changes. For distal changes in conductance, the sign of the change in the magnitude of the input impedance can even reverse in the higher frequency range, so that increases in conductance would produce increases in impedance. This effect may explain the paradoxical increases in impedance at 100 Hz reported for motor neuron inhibitory postsynaptic potentials. Sine-wave impedance measurements were made in single embryonic chick spinal neurons in tissue culture, and gamma-aminobutyric acid (GABA) was iontophoretically applied alternately to the soma and to a neurite at a measured distance from the soma. The impedance changes produced by the GABA-induced conductance changes were consistent with the expectations from the mathematical modeling, but the results suggest that the axial resistance of the neurites must be quite high in some cases. Distortions due to microelectrode capacitance and stray capacitances in the input stage of single-electrode bridge amplifiers can make sine-wave impedance measurements impossible. This difficulty was eliminated by modifications to the capacity compensation circuit of an active bridge amplifier. Noise and distortion of several other types can also introduce serious errors. Methods for minimizing such problems are discussed. In spite of its limitations, this method can be of great practical value, because it can give the electrotonic location of spontaneously occurring membrane conductance changes in single neurons even when unitary synaptic potentials cannot be resolved. These methods are currently being applied to hippocampal pyramidal cells in vivo to locate conductance changes during the electroencephalogram (EEG) theta-rhythm in rats. In such laminated structures, the determination of the anatomical source of a group of active synapses can be aided by location of the resultant membrane conductance changes.

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Immunoglobulin E mediated membrane conductance changes in rat basophilic leukemia cells

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y88-056 ◽

1988 ◽

Vol 66 (3) ◽

pp. 328-331 ◽

Cited By ~ 3

Author(s):

Carlos Barajas-López ◽

Jan D. Huizinga

Keyword(s):

Immunoglobulin E ◽

Calcium Influx ◽

Membrane Conductance ◽

Membrane Resistance ◽

Leukemia Cells ◽

Rat Basophilic Leukemia Cells ◽

Conductance Changes ◽

Electrophysiological Effects ◽

Basophilic Leukemia ◽

Stimulation Of

Electrophysiological effects of anaphylactic stimulation of rat basophilic leukemia cells (RBL-2H3) were studied using conventional microelectrodes. Stimulation of passively sensitized cells by anti-immunoglobulin E resulted in hyperpolarization followed by depolarization. These changes in membrane polarization were associated with a decrease in input membrane resistance. No effect of anaphylactic stimulation was seen in Ca2+-free solution or when Ca2+ influx was blocked by Co2+, but it was mimicked by the Ca2+ ionophore A-23187. This suggests that the changes in ionic conductances were associated with calcium influx. These results support the hypothesis that membrane conductance changes are involved in the stimulus-secretion process of the RBL-2H3 cells.

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Effect of tetraethylammonium on tonic airway smooth muscle: initiation of phasic electrical activity

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1975.228.2.633 ◽

1975 ◽

Vol 228 (2) ◽

pp. 633-636 ◽

Cited By ~ 52

Author(s):

EA Kroeger ◽

NL Stephens

Keyword(s):

Mechanical Properties ◽

Smooth Muscle ◽

Electrical Activity ◽

Action Potentials ◽

Membrane Conductance ◽

Mechanical Activity ◽

Myogenic Response ◽

Intracellular Recordings ◽

External Stimulation ◽

Length Constant

We have previously shown that in the presence of tetraethylammonium (TEA, 6.7-67 mM) phasic mechanical activity and a myogenic response (MR) to quick stretch are produced in normally multi-unit tracheal smooth muscle. The present studies were designed to investigate the electrophysiological basis for these changes in the mechanical properties of the muscle. Intracellular recordings showed that in the presence of TEA the membrane was partially depolarized and trains of small (8-20 mV), decrementally conducted action potentials were produced spontaneously at a frequency of 15-20/min. Action potentials could also be stimulated by external electrodes, and the conduction velocity over short distances was 0.84 plus or minus 0.2 cm/s. Membrane conductance and rectification, as measured by the magnitude of electrotonic potentials in response to external stimulation, were reduced in the presence of TEA. The length constant was increased from 1.6 plus or minus 0.1 to 2.8 plus or minus 0.2 mm. These results are consistent with the notion that TEA produces phasic membrane electrical activity by reducing P-K.

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Gating of Afferent Input by a Central Pattern Generator

Journal of Neurophysiology ◽

10.1152/jn.1999.81.2.950 ◽

1999 ◽

Vol 81 (2) ◽

pp. 950-953 ◽

Cited By ~ 8

Author(s):

Ralph A. DiCaprio

Keyword(s):

Central Pattern Generator ◽

Sensory Input ◽

Motor Pattern ◽

Pattern Generator ◽

Afferent Input ◽

Inhibitory Input ◽

Cycle Period ◽

Intracellular Recordings ◽

Afferent Fibers ◽

Sufficient Magnitude

Gating of afferent input by a central pattern generator. Intracellular recordings from the sole proprioceptor (the oval organ) in the crab ventilatory system show that the nonspiking afferent fibers from this organ receive a cyclic hyperpolarizing inhibition in phase with the ventilatory motor pattern. Although depolarizing and hyperpolarizing current pulses injected into a single afferent will reset the ventilatory motor pattern, the inhibitory input is of sufficient magnitude to block afferent input to the ventilatory central pattern generator (CPG) for ∼50% of the cycle period. It is proposed that this inhibitory input serves to gate sensory input to the ventilatory CPG to provide an unambiguous input to the ventilatory CPG.

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A novel method for measuring membrane conductance changes by a voltage-sensitive optical probe

FEBS Letters ◽

10.1016/0014-5793(90)80727-z ◽

1990 ◽

Vol 263 (1) ◽

pp. 155-158 ◽

Cited By ~ 2

Author(s):

Yosef Rosemberg ◽

Rafi Korenstein

Keyword(s):

Membrane Conductance ◽

Optical Probe ◽

Conductance Changes ◽

Novel Method

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Enhanced Monitoring of Nanosecond Electric Pulse-Evoked Membrane Conductance Changes in Whole-Cell Patch Clamp Experiments

The Journal of Membrane Biology ◽

10.1007/s00232-016-9902-5 ◽

2016 ◽

Vol 249 (5) ◽

pp. 633-644 ◽

Cited By ~ 11

Author(s):

Jihwan Yoon ◽

Normand Leblanc ◽

Josette Zaklit ◽

P. Thomas Vernier ◽

Indira Chatterjee ◽

...

Keyword(s):

Patch Clamp ◽

Electric Pulse ◽

Membrane Conductance ◽

Whole Cell ◽

Cell Patch Clamp ◽

Whole Cell Patch Clamp ◽

Conductance Changes

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Mechanism of activation of Xenopus CFTR by stimulation of PKC

AJP Cell Physiology ◽

10.1152/ajpcell.00229.2004 ◽

2004 ◽

Vol 287 (5) ◽

pp. C1256-C1263 ◽

Cited By ~ 6

Author(s):

Yongyue Chen ◽

Guillermo A. Altenberg ◽

Luis Reuss

Keyword(s):

Single Channel ◽

Membrane Conductance ◽

Transmembrane Conductance Regulator ◽

Transmembrane Conductance ◽

Open Probability ◽

Substituted Cysteine Accessibility ◽

Maximal Stimulation ◽

A Minor ◽

Cystic Fibrosis Transmembrane ◽

Stimulation Of

PKA-mediated phosphorylation of the regulatory (R) domain plays a major role in the activation of the human cystic fibrosis transmembrane conductance regulator (hCFTR). In contrast, the effect of PKC-mediated phosphorylation is controversial, smaller than that of PKA, and dependent on the cell type. In the present study, we expressed Xenopus CFTR ( XCFTR) and hCFTR in Xenopus oocytes and examined their responses (i.e., macroscopic membrane conductance) to maximal stimulation by PKC and PKA agonists. With XCFTR, the average response to PKC was approximately sixfold that of PKA stimulation. In contrast, with hCFTR, the response to PKC was ∼90% of the response to PKA stimulation. The reason for these differences was the small response of XCFTR to PKA stimulation. Using the substituted cysteine accessibility method, we found no evidence for insertion of functional CFTR channels in the plasma membrane in response to PKC stimulation. The increase in macroscopic conductance in response to PKC stimulation of XCFTR was due to an approximately fivefold increase in single-channel open probability, with a minor (∼30%) increase in single-channel conductance. The responses of XCFTR to PKC stimulation and of hCFTR to PKA stimulation were mediated by similar increases in Po. In both instances, there were no changes in the number of channels in the membrane. We speculate that in animals other than humans, PKC stimulation may be the dominant mechanism for activation of CFTR.

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ELECTRIC IMPEDANCE OF SINGLE MARINE EGGS

The Journal of General Physiology ◽

10.1085/jgp.21.5.591 ◽

1938 ◽

Vol 21 (5) ◽

pp. 591-599 ◽

Cited By ~ 21

Author(s):

Kenneth S. Cole ◽

Howard J. Curtis

Keyword(s):

Preliminary Data ◽

Sea Water ◽

Membrane Conductance ◽

Glass Tube ◽

Alternating Current ◽

Electric Impedance ◽

Frequency Range ◽

Impedance Measurements ◽

Membrane Capacity ◽

Thin Walled

Alternating current impedance measurements have been made on several single marine eggs over the frequency range from 1 to 2500 kilocycles per second. The eggs were placed in the center of a short capillary made by heating the end of a 2 mm. thin walled glass tube until it nearly closed, and electrodes were placed in the sea water on each side of the egg. When it is assumed that the membrane conductance is negligible, the membrane capacity and internal resistances of unfertilized and fertilized Arbacia eggs agree with the values obtained from suspensions. Preliminary data on centrifugally separated half Arbacia eggs, and whole Cumingia and Chaetopterus eggs are given.

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