Electrical Properties of the Basolateral Membrane of Hair Cells — A Review

1990 ◽  
pp. 51-63 ◽  
Author(s):  
C. J. Kros
Keyword(s):  
Electrical Properties ◽  
Hair Cells ◽  
Basolateral Membrane

scholarly journals Individual synaptic vesicles mediate stimulated exocytosis from cochlear inner hair cells

2018 ◽  
Vol 115 (50) ◽  
pp. 12811-12816 ◽  
Author(s):  
Chad Paul Grabner ◽  
Tobias Moser
Keyword(s):  
Hair Cells ◽  
Synaptic Vesicles ◽  
Basolateral Membrane ◽  
Mean Amplitude ◽  
Auditory Pathway ◽  
Inner Hair Cell ◽  
Excitatory Postsynaptic Currents ◽  
High Level ◽  
High Degree ◽  
Channel Type

Spontaneous excitatory postsynaptic currents (sEPSCs) measured from the first synapse in the mammalian auditory pathway reach a large mean amplitude with a high level of variance (CV between 0.3 and 1). This has led some to propose that each inner hair cell (IHC) ribbon-type active zone (AZ), on average, releases ∼6 synaptic vesicles (SVs) per sEPSC in a coordinated manner. If true, then the predicted change in membrane capacitance (Cm) for such multivesicular fusion events would equate to ∼300 attofarads (aF). Here, we performed cell-attached Cm measurements to directly examine the size of fusion events at the basolateral membrane of IHCs where the AZs are located. The frequency of events depended on the membrane potential and the expression of Cav1.3, the principal Ca2+-channel type of IHCs. Fusion events averaged 40 aF, which equates to a normal-sized SV with an estimated diameter of 37 nm. The calculated SV volumes showed a high degree of variance (CV > 0.6). These results indicate that SVs fused individually with the plasma membrane during spontaneous and evoked release and SV volume may contribute more variability in EPSC amplitude than previously assumed.

Two types of voltage-dependent potassium channels in outer hair cells from the guinea pig cochlea

1999 ◽  
Vol 277 (5) ◽  
pp. C913-C925 ◽  
Author(s):  
Thierry van den Abbeele ◽  
Jacques Teulon ◽  
Patrice Tran Ba Huy
Keyword(s):  
Guinea Pig ◽  
Hair Cells ◽  
Basolateral Membrane ◽  
Outer Hair Cells ◽  
Catalytic Subunit ◽  
Patch Clamp Technique ◽  
Open Probability ◽  
Guinea Pig Cochlea ◽  
Voltage Dependent ◽  
Inside Out

Cell-attached and cell-free configurations of the patch-clamp technique were used to investigate the conductive properties and regulation of the major K+channels in the basolateral membrane of outer hair cells freshly isolated from the guinea pig cochlea. There were two major voltage-dependent K+ channels. A Ca2+-activated K+ channel with a high conductance (220 pS, P K/ P Na= 8) was found in almost 20% of the patches. The inside-out activity of the channel was increased by depolarizations above 0 mV and increasing the intracellular Ca2+concentration. External ATP or adenosine did not alter the cell-attached activity of the channel. The open probability of the excised channel remained stable for several minutes without rundown and was not altered by the catalytic subunit of protein kinase A (PKA) applied internally. The most frequent K+ channel had a low conductance and a small outward rectification in symmetrical K+ conditions (10 pS for inward currents and 20 pS for outward currents, P K/ P Na= 28). It was found significantly more frequently in cell-attached and inside-out patches when the pipette contained 100 μM acetylcholine. It was not sensitive to internal Ca2+, was inhibited by 4-aminopyridine, was activated by depolarization above −30 mV, and exhibited a rundown after excision. It also had a slow inactivation on ensemble-averaged sweeps in response to depolarizing pulses. The cell-attached activity of the channel was increased when adenosine was superfused outside the pipette. This effect also occurred with permeant analogs of cAMP and internally applied catalytic subunit of PKA. Both channels could control the cell membrane voltage of outer hair cells.

scholarly journals Characterization of the basolateral membrane conductance of Necturus urinary bladder.

1987 ◽  
Vol 89 (4) ◽  
pp. 541-562 ◽  
Author(s):  
J R Demarest ◽  
A L Finn
Keyword(s):  
Electrical Properties ◽  
Basolateral Membrane ◽  
Membrane Conductance ◽  
Transference Numbers ◽  
Sudden Increase ◽  
Membrane Selectivity ◽  
Rapid Changes ◽  
K Concentration ◽  
Passive Electrical Properties

Necturus urinary bladders stripped of serosal muscle and connective tissue were impaled through their basolateral membranes with microelectrodes in experiments that permitted rapid changes in the ion composition of the serosal solution. The transepithelial electrical properties exhibited a marked seasonal variation that could be attributed to variations in the conductance of the shunt pathway, apical membrane selectivity, and basolateral Na+ transport. In contrast, the passive electrical properties of the basolateral membrane remained constant throughout the year. The apparent transference numbers (Ti) of the basolateral membrane for K+ and Cl- were determined from the effect on the basolateral membrane equivalent electromotive force of a sudden increase in the serosal K+ concentration from 2.5 to 50 mM/liter or a decrease in the Cl- concentration from 101 to 10 mM/liter. TK and TCl were 0.71 +/- 0.05 and 0.04 +/- 0.01, respectively. The basolateral K+ conductance could be blocked by Ba2+ (0.5 mM), Cs+ (10 mM), or Rb+ (10 mM), but was unaffected by 3,4-diaminopyridine (100 microM), decamethonium (100 microM), or tetraethylammonium (10 mM). We conclude that a highly selective K+ conductance dominates the electrical properties of the basolateral membrane and that this conductance is different from those found in nerve and muscle membranes.

Effects of changes in serosal chloride on electrical properties of toad urinary bladder

1983 ◽  
Vol 244 (1) ◽  
pp. C11-C16 ◽  
Author(s):  
J. Narvarte ◽  
A. L. Finn
Keyword(s):  
Electrical Properties ◽  
Urinary Bladder ◽  
Short Circuit ◽  
Basolateral Membrane ◽  
Chloride Concentration ◽  
Concentration Addition ◽  
Toad Urinary Bladder ◽  
Base Line ◽  
Transepithelial Potential ◽  
Sodium Conductance

Conventional microelectrode and tracer flux techniques were used to study the effects of reduction in serosal chloride concentration ([Cl]s) on the electrical properties of toad urinary bladder epithelium. Reduction in [Cl]s resulted in a transient change in transepithelial potential (Vms) (and of apical and basolateral membrane potentials) that was inversely dependent on the base-line values of those potentials. In all cases, however, there was a decrease in transepithelial resistance (Rt) that was explained by an increase in the sodium conductance of the apical membrane. In tissues in which the transepithelial potential increased, there was a rise in the active mucosal-to-serosal sodium flux. The increase in conductance was directly related to the increase in short-circuit current. The changes in Vms and Rt brought about by reduction in [Cl]s were prevented by agents known to modify sodium transport, including low mucosal sodium concentration, addition of amiloride or amphotericin B to the mucosal solution, or of ouabain to the serosal solution. The results are best explained by a primary effect of chloride reduction on sodium extrusion across the basolateral membrane, with a secondary increase in apical sodium conductance. In addition, the data provide new evidence for the existence of a basolateral chloride conductance pathway.

Distribution of Ca2+ channels on cochlear outer hair cells revealed by fluorescent dihydropyridines

1996 ◽  
Vol 271 (3) ◽  
pp. C944-C949 ◽  
Author(s):  
T. Oshima ◽  
K. Ikeda ◽  
M. Furukawa ◽  
N. Ueda ◽  
H. Suzuki ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Hair Cells ◽  
Laser Scanning ◽  
Basolateral Membrane ◽  
Outer Hair Cells ◽  
Spatial Integration ◽  
Heterogeneous Distribution ◽  
Voltage Dependent ◽  
Basolateral Plasma Membrane ◽  
Ca2 Channels

Physiological evidence has shown that cochlear outer hair cells (OHC) possess L-type voltage-dependent Ca2+ channels through which Ca2+ enters the OHC during depolarization. Their subcellular distribution has, however, remained unclear. In this study, the distribution of L-type Ca2+ channels on the basolateral plasma membrane of OHC has been demonstrated by the use of a laser scanning confocal microscope (LSCM) and a fluorescent probe DMBODIPY-DHP. The fluorescent staining pattern on the basolateral wall is nonuniform, suggesting a heterogeneous distribution of the channels in the plasma membrane. Direct imaging of intracellular Ca2+ visualized in real time by means of the LSCM and the fluorescent Ca2+ probe fluo 3 revealed temporal and spatial integration of Ca2+ movements and Ca2+ channel distribution. Exposure to high-K+ solution induced heterogeneity in the subcellular increase in the intracellular Ca2+ concentration. These results suggest that the heterogeneous distribution of L-type Ca2+ channels on the basolateral membrane might induce heterogeneous intracellular Ca2+ distribution during electrical activity in the OHC.

scholarly journals Effects of ouabain on fluid transport and electrical properties of Necturus gallbladder. Evidence in favor of a neutral basolateral sodium transport mechanism.

1979 ◽  
Vol 73 (4) ◽  
pp. 385-402 ◽  
Author(s):  
L Reuss ◽  
E Bello-Reuss ◽  
T P Grady
Keyword(s):  
Electrical Properties ◽  
Cell Membranes ◽  
Fluid Transport ◽  
Prolonged Exposure ◽  
Basolateral Membrane ◽  
Bathing Solution ◽  
Na Transport ◽  
Bathing Medium ◽  
Necturus Gallbladder ◽  
Before And After

Net fluid transport (Jv) and electrical properties of the cell membranes and paracellular pathway of Necturus gallbladder epithelium were studied before and after the addition of ouabain (10(-4) M) to the serosal bathing medium. The glycoside inhibited Jv by 70% in 15 min and by 100% in 30 min. In contrast, the potentials across both cell membranes did not decrease significantly until 20 min of exposure to ouabain. At 30 min, the basolateral membrane potential (Vcs) fell only by ca 7 mV. If basolateral Na transport were electrogenic, with a coupling ratio (Na:K) of 3:2, the reductions of Vcs at 15 and 30 min should be 12--15 and 17--21 mV, respectively. Thus, we conclude that the mechanism of Na transport from the cells to the serosal bathing solution is not electrogenic under normal transport conditions. The slow depolarization observed in ouabain is caused by a fall of intracellular K concentration, and by a decrease in basolateral cell membrane K permeability. Prolonged exposure to ouabain results also in an increase in paracellular K selectivity, with no change of P Na/P Cl.

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