Studies of solitary semicircular canal hair cells in the adult pigeon. I. Frequency- and time-domain analysis of active and passive membrane properties

1989 ◽  
Vol 62 (4) ◽  
pp. 924-934 ◽  
Author(s):  
M. J. Correia ◽  
B. N. Christensen ◽  
L. E. Moore ◽  
D. G. Lang
Keyword(s):  
Membrane Potential ◽  
Frequency Domain ◽  
Hair Cells ◽  
Time Domain ◽  
Input Resistance ◽  
Membrane Properties ◽  
Resting Potential ◽  
The Mean ◽  
Passive Membrane Properties ◽  
Passive Membrane

1. Hair cells were enzymatically dissociated from the neuroepithelium (cristae ampullares) of the semicircular canals of white king pigeons (Columba livia). Those hair cells determined to be type II by an anatomic criterion, the ratio of the minimum width of the neck to the width of the cuticular plate, were studied with the use of the whole cell patch-clamp technique. 2. The mean +/- SD zero-current membrane potential, Vz, was found to be -54 +/- 12 mV for anterior crista hair cells (n = 71), -62 +/- 14 mV for posterior crista hair cells (n = 14), and -55 +/- 12 mV for lateral (horizontal) crista hair cells (n = 18). The mean +/- SD value of Vz for hair cells from all cristae (n = 103) was -56 +/- 13 mV. 3. Active and passive membrane properties were calculated in the time domain, in voltage- or current-clamp mode, from responses to voltage or current pulses and, in the frequency domain, by fitting a membrane model to admittance magnitude and phase data resulting from current responses to sum-of-sines voltages at different d.c. levels of voltage-clamp membrane potential. 4. The average value +/- SE of input resistance (Rin), over the range from -100 to -60 mV, was found to 1.5 +/- 0.3 G omega from a mean-voltage-as-a-function-of-current plot, V-I, (n = 7) and a mean of 1.4 +/- 0.3 G omega from individual (n = 15) current-as-a-function-of-voltage plots, I-V. A lower mean value 0.8 +/- 0.4 G omega was obtained for the input resistance from frequency-domain calculations for a different set of cells (n = 21). Also, in two different sets of cells, average input capacitance (Cin) was determined to be 12 +/- 3 pF (n = 7) from time-domain estimates and 14 +/- 3 pF (n = 21) from frequency-domain estimates. The (Rin)(Cin) product was 11 ms based on frequency-domain estimates and 17 ms from time-domain estimates. 5. I-V curves for hair cells voltage clamped at -60 mV showed some anomalous rectification for hyperpolarizations between -60 and -120 mV but no detectable N-shape for depolarizations between -50 and 90 mV. The I-V relation showed increasing slope with depolarization through the resting potential (Vz) and increased linearly between -40 and 80 mV; the best-fit straight-line maximum slope conductance for six cells over this range was 17.4 +/- 0.3 nS.(ABSTRACT TRUNCATED AT 400 WORDS)

Perforated patch-clamp analysis of the passive membrane properties of three classes of hippocampal neurons

1992 ◽  
Vol 67 (3) ◽  
pp. 508-529 ◽  
Author(s):  
N. Spruston ◽  
D. Johnston
Keyword(s):  
Membrane Potential ◽  
Hippocampal Neurons ◽  
Pyramidal Neurons ◽  
Physiological Saline ◽  
Membrane Properties ◽  
Resting Potential ◽  
Voltage Dependent ◽  
Perforated Patch Clamp ◽  
Passive Membrane Properties ◽  
Passive Membrane

1. Perforated patch-clamp recordings were made from the three major classes of hippocampal neurons in conventional in vitro slices prepared from adult guinea pigs. This technique provided experimental estimates of passive membrane properties (input resistance, RN, and membrane time constant, tau m) determined in the absence of the leak conductance associated with microelectrode impalement or the washout of cytoplasmic constituents associated with conventional whole-cell recordings. 2. To facilitate comparison of our data with previous results and to determine the passive membrane properties under conditions as physiological as possible, recordings were made at the resting potential, in physiological saline, and without any added blockers of voltage-dependent conductances. 3. Membrane-potential responses to current steps were analyzed, and four criteria were used to identify voltage responses that were the least affected by activation of voltage-dependent conductances. tau m was estimated from the slowest component (tau 0) of multiexponential fits of responses deemed passive by these criteria. RN was estimated from the slope of the linear region in the hyperpolarizing direction of the voltage-current relation. 4. It was not possible to measure purely passive membrane properties that were completely independent of membrane potential in any of the three classes of hippocampal neurons. Changing the membrane potential by constant current injection resulted in changes in RN and tau 0; subthreshold depolarization produced an increase, and hyperpolarization a decrease, in both RN and tau 0 for all three classes of hippocampal neurons. 5. Each of the three classes of hippocampal neurons also displayed a depolarizing "sag" during larger hyperpolarizing voltage transients. To evaluate the effect of the conductances underlying this sag on passive membrane properties, 2-5 mM Cs+ was added to the physiological saline. Extracellular Cs+ effectively blocked the sag in all three classes of hippocampal neurons, but the effect of Cs+ on RN, tau 0, and the voltage dependence of these parameters was unique for each class of neurons. 6. CA1 pyramidal neurons had an RN of 104 +/- 10 (SE) M omega and tau 0 of 28 +/- 2 ms at a resting potential of -64 +/- 2 mV (n = 12). RN and tau 0 were larger at more depolarized potentials in these neurons, but the addition of Cs+ to the physiological saline reversed this voltage dependence. 7. CA3 pyramidal neurons had an RN of 135 +/- 8 M omega and tau 0 of 66 +/- 4 ms at a resting potential of -64 +/- 1 mV (n = 14).(ABSTRACT TRUNCATED AT 400 WORDS)

Effects of ouabain on background and voltage-dependent currents in canine colonic myocytes

1990 ◽  
Vol 259 (3) ◽  
pp. C402-C408 ◽  
Author(s):  
E. P. Burke ◽  
K. M. Sanders
Keyword(s):  
Membrane Potential ◽  
Potential Gradient ◽  
Circular Muscle ◽  
Input Resistance ◽  
Pump Current ◽  
Muscle Layer ◽  
Membrane Properties ◽  
Resting Potential ◽  
Voltage Dependent ◽  
In Cells

Previous studies have suggested that the membrane potential gradient across the circular muscle layer of the canine proximal colon is due to a gradient in the contribution of the Na(+)-K(+)-ATPase. Cells at the submucosal border generate approximately 35 mV of pump potential, whereas at the myenteric border the pump contributes very little to resting potential. Results from experiments in intact muscles in which the pump is blocked are somewhat difficult to interpret because of possible effects of pump inhibitors on membrane conductances. Therefore, we studied isolated colonic myocytes to test the effects of ouabain on passive membrane properties and voltage-dependent currents. Ouabain (10(-5) M) depolarized cells and decreased input resistance from 0.487 +/- 0.060 to 0.292 +/- 0.040 G omega. The decrease in resistance was attributed to an increase in K+ conductance. Studies were also performed to measure the ouabain-dependent current. At 37 degrees C, in cells dialyzed with 19 mM intracellular Na+ concentration [( Na+]i), ouabain caused an inward current averaging 71.06 +/- 7.49 pA, which was attributed to blockade of pump current. At 24 degrees C or in cells dialyzed with low [Na+]i (11 mM), ouabain caused little change in holding current. With the input resistance of colonic cells, pump current appears capable of generating at least 35 mV. Thus an electrogenic Na+ pump could contribute significantly to membrane potential.

Biophysical Properties and Ionic Signature of Neuronal Progenitors of the Postnatal Subventricular Zone In Situ

2003 ◽  
Vol 90 (4) ◽  
pp. 2291-2302 ◽  
Author(s):  
D. D. Wang ◽  
D. D. Krueger ◽  
A. Bordey
Keyword(s):  
Subventricular Zone ◽  
Brain Slices ◽  
Reversal Potential ◽  
Membrane Properties ◽  
Resting Potential ◽  
Mammalian Brain ◽  
Specific Class ◽  
Neuronal Progenitors ◽  
Passive Membrane Properties ◽  
Passive Membrane

Previous studies have reported the presence of neuronal progenitors in the subventricular zone (SVZ) and rostral migratory stream (RMS) of the postnatal mammalian brain. Although many studies have examined the survival and migration of progenitors after transplantation and the factors influencing their proliferation or differentiation, no information is available on the electrophysiological properties of these progenitors in a near-intact environment. Thus we performed whole cell and cell-attached patch-clamp recordings of progenitors in brain slices containing either the SVZ or the RMS from postnatal day 15 to day 25 mice. Both regions displayed strong immunoreactivity for nestin and neuron-specific class III β-tubulin, and recorded cells displayed a morphology typical of the neuronal progenitors known to migrate throughout the SVZ and RMS to the olfactory bulb. Recorded progenitors had depolarized zero-current resting potentials (mean more depolarized than –28 mV), very high input resistances (about 4 GΩ), and lacked action potentials. Using the reversal potential of K+ currents through a cell-attached patch a mean resting potential of –59 mV was estimated. Recorded progenitors displayed Ca2+-dependent K+ currents and TEA-sensitive-delayed rectifying K+ (KDR) currents, but lacked inward K+ currents and transient outward K+ currents. KDR currents displayed classical kinetics and were also sensitive to 4-aminopyridine and α-dendrotoxin, a blocker of Kv1 channels. Na+ currents were found in about 60% of the SVZ neuronal progenitors. No developmental changes were observed in the passive membrane properties and current profile of neuronal progenitors. Together these data suggest that SVZ neuronal progenitors display passive membrane properties and an ionic signature distinct from that of cultured SVZ neuronal progenitors and mature neurons.

Bistable membrane potential of the ciliate Coleps hirtus

2000 ◽  
Vol 203 (4) ◽  
pp. 757-764
Author(s):  
P. Rudberg ◽  
O. Sand
Keyword(s):  
Membrane Potential ◽  
Deep Level ◽  
Input Resistance ◽  
Membrane Properties ◽  
Resting Potential ◽  
Inward Rectification ◽  
Free Solution ◽  
Shallow Level ◽  
Swimming Pattern ◽  
Potential Level

In normal recording solution, the swimming pattern of the freshwater ciliate Coleps hirtus, belonging to the class Prostomatea, consists of alternating periods of nearly linear forward swimming and circular swimming within a small area. Current-clamp recordings were performed to elucidate the mechanism for this behaviour. No members of this class have previously been studied using electrophysiological techniques. The ciliates were maintained in culture and fed on the planctonic alga Rhodomonas minuta. The membrane potential showed spontaneous shifts between a more negative (deep) level of approximately −50 mV and a less negative (shallow) level of approximately −30 mV. The input resistance and capacitance at the more negative level were approximately 400 M capomega and 120 pF respectively. C. hirtus displayed a pronounced inward rectification, which was virtually insensitive to 1 mmol l(−1) Cs(+) and almost completely blocked by 1 mmol l(−1) Ba(2+). Depolarising current injections failed to evoke graded, regenerative Ca(2+) spikes. However, current-induced depolarisations from the more negative potential level (−50 mV) showed a pronounced shoulder during the repolarising phase. Increased current injections prolonged the shoulder, which occasionally stabilised at the shallow membrane potential (−30 mV). The membrane potential could be shifted to the deep level by brief hyperpolarising current injections. Similar biphasic membrane properties have not been reported previously in any ciliate. The bistability of the membrane potential was abolished in Ca(2+)-free solution containing Co(2+) or Mg(2+). In Ca(2+)-free solution containing 1 mmol l(−1) Ba(2+), brief depolarising current injections at the deep potential level evoked all-or-nothing action potentials with a prolonged plateau coinciding with the shallow potential. We conclude that the deep membrane potential in C. hirtus corresponds to the traditional resting potential, whereas the shallow level is a Ca(2+)-dependent plateau potential. In normal solution, the direction of the ciliary beat was backwards at the deep potential level and forwards at the shallow membrane potential, probably reflecting the two main phases of the swimming pattern.

scholarly journals Two Functional Classes of Rod Bipolar Cells in the Healthy and Degenerated Optogenetically Treated Murine Retina

2022 ◽  
Vol 15 ◽  
Author(s):  
Giulia Schilardi ◽  
Sonja Kleinlogel
Keyword(s):  
Membrane Potential ◽  
Bipolar Cell ◽  
Bipolar Cells ◽  
Membrane Properties ◽  
Current Voltage ◽  
Passive Membrane Properties ◽  
Rod Bipolar Cells ◽  
Passive Membrane

Bipolar cells have become successful targets for optogenetic gene therapies that restore vision after photoreceptor degeneration. However, degeneration was shown to cause changes in neuronal connectivity and protein expression, which may impact the quality of synthetically restored signaling. Further, the expression of an optogenetic protein may alter passive membrane properties of bipolar cells affecting signal propagation. We here investigated the passive membrane properties of rod bipolar cells in three different systems, the healthy retina, the degenerated retina, and the degenerated retina expressing the optogenetic actuator Opto-mGluR6. We found that, based on the shape of their current-voltage relations, rod bipolar cells in healthy and degenerated retinas form two clear functional groups (type 1 and type 2 cells). Depolarizing the membrane potential changed recorded current-voltage curves from type 1 to type 2, confirming a single cell identity with two functional states. Expression of Opto-mGluR6 did not alter the passive properties of the rod bipolar cell. With progressing degeneration, dominant outward rectifying currents recorded in type 2 rod bipolar cells decreased significantly. We demonstrate that this is caused by a downregulation of BK channel expression in the degenerated retina. Since this BK conductance will normally recover the membrane potential after RBCs are excited by open TRPM1 channels, a loss in BK will decrease high-pass filtering at the rod bipolar cell level. A better understanding of the changes of bipolar cell physiology during retinal degeneration may pave the way to optimize future treatment strategies of blindness.

In vitro electrophysiology of developing genioglossal motoneurons in the rat

1993 ◽  
Vol 70 (4) ◽  
pp. 1401-1411 ◽  
Author(s):  
P. A. Nunez-Abades ◽  
J. M. Spielmann ◽  
G. Barrionuevo ◽  
W. E. Cameron
Keyword(s):  
Membrane Potential ◽  
Action Potential ◽  
Reversal Potential ◽  
Input Resistance ◽  
Membrane Properties ◽  
Inward Rectification ◽  
Postnatal Change ◽  
The Mean ◽  
Made In

1. Experiments were performed to determine the change in membrane properties of genioglossal (GG) motoneurons during development. Intracellular recordings were made in 127 GG motoneurons from rats postnatal ages 1-30 days. 2. The input resistance (R(in)) and the membrane time constant (t(aum)) decreased between 5-6 and 13-15 days from 84.8 +/- 25.4 (SD) to 47.0 +/- 18.9 M omega (P < 0.01) and from 10.0 +/- 4.2 to 7.3 +/- 3.3 ms (P < 0.05), respectively. During this period, the rheobase (Irh) increased (P < 0.01) from 0.13 +/- 0.07 to 0.27 +/- 0.14 nA, and the percentage of cells exhibiting inward rectification increased from 5 to 40%. Voltage threshold (Vthr) of the action potential remained unchanged postnatally. 3. There was also a postnatal change in the shape of the action potential. Specifically, between 1-2 and 5-6 days, there was a decrease (P < 0.05) in the spike half-width from 2.23 +/- 0.53 to 1.45 +/- 0.44 ms, resulting, in part, from a steepening (P < 0.05) of the slope of the falling phase of the action potential from 21.6 +/- 10.1 to 32.9 +/- 13.1 mV/ms. The slope of the rising phase also increased significantly (P < 0.01) between 1-2 and 13-15 days from 68.4 +/- 31.0 to 91.4 +/- 44.3 mV/ms. 4. The average duration of the medium afterhyperpolarization (mAHPdur) decreased (P < 0.05) between 1-2 (193 +/- 53 ms) and 5-6 days (159 +/- 43 ms). Whereas the mAHPdur was found to be independent of membrane potential, there was a linear relationship between the membrane potential and the amplitude of the medium AHP (mAHPamp). From this latter relationship, a reversal potential for the mAHPamp was extrapolated to be -87 mV. No evidence for the existence of a slow AHP was found in these developing motoneurons. 5. All cells analyzed (n = 74) displayed adaptation during the first three spikes. The subsequent firing pattern was classified into two groups, adapting and nonadapting. Cells at birth were all adapting, whereas all cells but two from animals 13 days and older were nonadapting. At the intermediate age (5-6 days), the minority (27%) was adapting and the majority (73%) was nonadapting. 6. The mean slope of primary range for the first interspike interval (1st ISI) was approximately 90 Hz/nA. This value was similar for both adapting and nonadapting cells and did not change postnatally.(ABSTRACT TRUNCATED AT 400 WORDS)

Passive membrane properties of isolated feline ventricular myocytes

1985 ◽  
Vol 248 (5) ◽  
pp. H622-H630
Author(s):  
S. R. Houser ◽  
A. Bahinski ◽  
L. H. Silver
Keyword(s):  
Membrane Potential ◽  
Cardiac Muscle ◽  
Membrane Permeability ◽  
Functional Relationship ◽  
Ventricular Myocytes ◽  
Input Resistance ◽  
Membrane Properties ◽  
Independence Principle ◽  
Tissue Matrix ◽  
Passive Membrane Properties

Membrane properties of adult mammalian cardiac muscle are difficult to define mainly because of experimental complications arising from complex packing of myocytes in the tissue matrix. Isolated feline myocytes were used in the present study to avoid these complications. The objectives of this study were to define the functional relationship between passive unidirectional transmembrane potassium (K+) fluxes, membrane permeability to K+ (PK), and membrane K+ (Ko) dependency of this relationship. Passive (ouabain-insensitive) components of unidirectional K+ fluxes were measured with 42K, and membrane potential (Em) and membrane (slope) conductance (gm) were measured with electrophysiological techniques. Myocytes studied in solutions with 5 mM K+o had normal resting potentials (-81 +/- 1 mV). The input resistance and membrane time constant were 2.72 +/- 0.47 X 10(-7) omega and 7.01 +/- 1.0 ms, respectively. When K+o was lowered Em hyperpolarized, input resistance (Ri) increased, and K+ fluxes decreased. When K+o was increased Em depolarized, Ri decreased, and K+ fluxes increased. These data were combined to determine whether K+ fluxes obey the independence principle and to calculate PK and gK. The results obtained support the idea that 1) unidirectional K+ fluxes do not obey the independence principle, 2) PK is much greater than the membrane permeability to other ions, and 3) the gK calculated from passive K+ fluxes was similar to the gm measured electrically (at all K+o's tested).

Nonuniform passive membrane properties of rat lumbar sympathetic ganglion cells

1987 ◽  
Vol 57 (3) ◽  
pp. 633-644 ◽  
Author(s):  
S. J. Redman ◽  
E. M. McLachlan ◽  
G. D. Hirst
Keyword(s):  
Time Constant ◽  
Sympathetic Neurons ◽  
Potassium Conductance ◽  
Membrane Conductance ◽  
Input Resistance ◽  
Membrane Properties ◽  
Voltage Response ◽  
Bathing Solution ◽  
Passive Membrane Properties ◽  
Passive Membrane

We have studied the passive membrane properties of sympathetic neurons in isolated lumbar paravertebral ganglia of young rats by recording the voltage response to small steps of current passed through an intracellular microelectrode. Substitution of Ba2+ (2.5 mM) for Ca2+ (2.5 mM) in the bathing solution increased the input resistance and the time constant of the voltage response, but the increase in time constant was disproportionately large relative to the increase in input resistance. After consideration of the passive electrical properties and the geometry of the soma and dendrites, it was concluded that the disproportionate change in input resistance and time constant could be explained if barium inactivated a resting potassium conductance that was concentrated in the distal dendrites. In the APPENDIX, the effect of nonuniform membrane conductance on the relationship between input resistance and time constant in models of these neurons is analyzed.

Properties of visceral primary afferent neurons in the nodose ganglion of the rabbit

1985 ◽  
Vol 54 (2) ◽  
pp. 245-260 ◽  
Author(s):  
C. E. Stansfeld ◽  
D. I. Wallis
Keyword(s):  
Action Potentials ◽  
Input Resistance ◽  
Nodose Ganglion ◽  
Time Dependent ◽  
Membrane Properties ◽  
Resting Potential ◽  
Inward Rectification ◽  
C Cells ◽  
Axonal Conduction ◽  
A Cells

The active and passive membrane properties of rabbit nodose ganglion cells and their responsiveness to depolarizing agents have been examined in vitro. Neurons with an axonal conduction velocity of less than 3 m/s were classified as C-cells and the remainder as A-cells. Mean axonal conduction velocities of A- and C-cells were 16.4 m/s and 0.99 m/s, respectively. A-cells had action potentials of brief duration (1.16 ms), high rate of rise (385 V/s), an overshoot of 23 mV, and relatively high spike following frequency (SFF). C-cells typically had action potentials with a "humped" configuration (duration 2.51 ms), lower rate of rise (255 V/s), an overshoot of 28.6 mV, an after potential of longer duration than A-cells, and relatively low SFF. Eight of 15 A-cells whose axons conducted at less than 10 m/s had action potentials of longer duration with a humped configuration; these were termed Ah-cells. They formed about 10% of cells whose axons conducted above 2.5 m/s. The soma action potential of A-cells was blocked by tetrodotoxin (TTX), but that of 6/11 C-cells was unaffected by TTX. Typically, A-cells showed strong delayed (outward) rectification on passage of depolarizing current through the soma membrane and time-dependent (inward) rectification on inward current passage. Input resistance was thus highly sensitive to membrane potential close to rest. In C-cells, delayed rectification was not marked, and slight time-dependent rectification occurred in only 3 of 25 cells; I/V curves were normally linear over the range: resting potential to 40 mV more negative. Data on Ah-cells were incomplete, but in our sample of eight cells time-dependent rectification was absent or mild. C-cells had a higher input resistance and a higher neuronal capacitance than A-cells. In a proportion of A-cells, RN was low at resting potential (5 M omega) but increased as the membrane was hyperpolarized by a few millivolts. A-cells were depolarized by GABA but were normally unaffected by 5-HT or DMPP. C-cells were depolarized by GABA in a similar manner to A-cells but also responded strongly to 5-HT; 53/66 gave a depolarizing response, and 3/66, a hyperpolarizing response. Of C-cells, 75% gave a depolarizing response to DMPP.(ABSTRACT TRUNCATED AT 400 WORDS)

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