ATP-induced current in isolated outer hair cells of guinea pig cochlea

1990 ◽  
Vol 63 (5) ◽  
pp. 1068-1074 ◽  
Author(s):  
T. Nakagawa ◽  
N. Akaike ◽  
T. Kimitsuki ◽  
S. Komune ◽  
T. Arima
Keyword(s):  
Guinea Pig ◽  
Hair Cells ◽  
Reversal Potential ◽  
Outer Hair Cells ◽  
Hill Coefficient ◽  
Induced Response ◽  
Induced Current ◽  
Patch Clamp Technique ◽  
Positive Direction ◽  
Guinea Pig Cochlea

1. Electrical and pharmacologic properties of ATP-induced current in outer hair cells isolated from guinea pig cochlea were investigated in the whole-cell recording mode by the use of a conventional patch-clamp technique. 2. Under current-clamp conditions, rapid application of ATP depolarized the outer hair cells resulting in an increase in conductance. The ATP-induced response did not show any desensitization during a continuous application. 3. At a holding potential of -70 mV, the ATP-induced inward current increased in a sigmoidal fashion over the concentration range between 3 microM and 1 mM. The half-maximum concentration (EC50) was 12 microM and the Hill coefficient was 0.93. 4. The ATP-induced current had a reversal potential near 6 mV, which was close to the theoretical value (1 mV) calculated from the Goldman-Hodgkin-Katz equation for permeable intra- and extracellular cations. 5. In the current-voltage (I-V) relationship for the ATP response, a slight inward-going rectification was observed at more positive potentials than the reversal potential. 6. The substitution of extracellular Na+ by equimolar choline+ shifted the reversal potential of the ATP-induced current to more negative values. The substitution of Cs+ in the internal solution by N-methyl-D-glucamine+ (NMG+) shifted it in the positive direction. The reversal potential of ATP-induced current was also shifted to positive values with increasing extracellular Ca2+ concentration. A decrease of intracellular Cl- by gluconate- did not affect the reversal potential, thereby indicating that the ATP-induced current is carried through a large cation channel.(ABSTRACT TRUNCATED AT 250 WORDS)

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 Effect of an ATP-Regulated Potassium Channel Opener, Nicorandil, on Isolated Outer Hair Cells of the Guinea Pig Cochlea

1998 ◽  
Vol 1998 (Supplement96) ◽  
pp. 23-30
Author(s):  
Akimitsu Kawai ◽  
Yukihiro Sato ◽  
Takeshi Akisada ◽  
Tsuyoshi Yoshihiro ◽  
Kotaro Take ◽  
...  
Keyword(s):  
Guinea Pig ◽  
Potassium Channel ◽  
Hair Cells ◽  
Outer Hair Cells ◽  
Potassium Channel Opener ◽  
Guinea Pig Cochlea ◽  
Channel Opener

Guinea Pig Vestibular Type I Hair Cells Can Show Reversible Shortening

1991 ◽  
Vol 1 (3) ◽  
pp. 241-250
Author(s):  
Pascale N.M. Lapeyre ◽  
Yves Cazals
Keyword(s):  
Guinea Pig ◽  
Hair Cells ◽  
Neck Region ◽  
Outer Hair Cells ◽  
Test Solution ◽  
Induced Response ◽  
Type I ◽  
Hypotonic Solution ◽  
Bathing Medium ◽  
Water Influx

Guinea pig isolated vestibular type I hair cells (VIHCs) were recently reported by our group to respond to high [KCl] solutions by an irreversible tilt of their neck region and sometimes by a sustained shortening and swelling. A possible osmotic contribution to these shape changes was investigated by substituting gluconate (G) for chloride in the test solution, so as to minimize water influx, and also by changing the osmotic pressure of the extracellular solution. For comparison, similar experiments were also undertaken on cochlear outer hair cells (OHCs). Utricular and ampullar type I hair cells were more difficult to isolate than OHCs and, like them, responded to an isotonic high [KCl] solution by a sustained shortening and widening, which were found to be reversible for most cells when rinsed with the control solution. In a high [KG] solution, all OHCs showed a shortening reversible in the test solution; among the VIHCs tested, two-thirds presented a slight sustained shortening without widening and a third showed a spontaneously reversible shortening, particularly at the neck level. VIHCs exposed to a high [N-methyl-D-glucamine chloride] solution, this impermeant cation replacing K+ for control, presented only a slight sustained shortening. In response to osmotic changes of the bathing medium, both VIHCs and OHCs showed a sustained shortening or elongation (the latter to a lesser degree) for hypo- and hyperosmotic solutions, respectively. The VIHCs and OHCs that presented a reversible shortening in a high [KG] solution widened concomitantly with their shortening, but to a smaller extent compared with what was observed in a high [KCl] solution, and this diameter increase was reversible in the test solution, unlike the widening observed in a hypotonic solution. These results show that a reversible shortening occurred for some VIHCs; they also indicate the involvement of two components in the KCl-induced response: one osmotic and another potassium-dependent.

Hyposmotic stimulation-induced nitric oxide production in outer hair cells of the guinea pig cochlea

2007 ◽  
Vol 227 (1-2) ◽  
pp. 59-70 ◽  
Author(s):  
Hiroko Takeda-Nakazawa ◽  
Narinobu Harada ◽  
Jing Shen ◽  
Nobuo Kubo ◽  
Hans-Peter Zenner ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Guinea Pig ◽  
Hair Cells ◽  
Outer Hair Cells ◽  
Nitric Oxide Production ◽  
Oxide Production ◽  
Guinea Pig Cochlea

Distribution of members of the PSD-95 family of MAGUK proteins at the synaptic region of inner and outer hair cells of the guinea pig cochlea

Synapse ◽  
2001 ◽  
Vol 40 (4) ◽  
pp. 258-268 ◽  
Author(s):  
Caroline Davies ◽  
Debora Tingley ◽  
Bechara Kachar ◽  
Robert J. Wenthold ◽  
Ronald S. Petralia
Keyword(s):  
Guinea Pig ◽  
Hair Cells ◽  
Outer Hair Cells ◽  
Guinea Pig Cochlea ◽  
Synaptic Region ◽  
Maguk Proteins
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