[ACh and ATP-induced current in isolated outer hair cells and Deiters' cells of guinea pig cochlea].
OBJECTIVE
To determine ACh- and ATP-induced currents in isolated outer hair cells of guinea pig cochlea, respectively.


METHODS
The whole-cell patch-clamp technique was used to investigate potential and concentration dependence of ACh- and ATP-induced ion currents.


RESULTS
ACh(100 mumol/L) induced an early inward current followed by a late outward current when the cells were voltage-clamped at -70 mV. Only outward current occurred when potential was over -60 mV and its reversal potential was (-80 +/- 5.61) mV(n = 6). When depolarization protocols were applied, amplitude of inward currents activated by ATP(100 mumol/L) decreased and reversed at (3.2 +/- 0.23) mV(n = 8). Ion currents activated by ATP (100 mumol/L) were also recorded from isolated Deiters' cells.


CONCLUSIONS
ACh-induced outward current was carried by K+ and ATP-induced inward current was through non-selective cations channel. Effects of ACh and ATP on OHCs were voltage dependent.
Yang
J
J
Department of Otorhinolaryngology Head and Neck Surgery, Renji Hospital, Shanghai Second Medical University, Shanghai 200001, China.
Wang
J
J
D000109:Acetylcholine / Q000494:pharmacology*; D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D003051:Cochlea / Q000166:cytology*; D006168:Guinea Pigs; D018072:Hair Cells, Auditory, Outer / Q000187:drug effects*; D066298:In Vitro Techniques; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000502:physiology
D015221:Potassium Channels; D000255:Adenosine Triphosphate; D000109:Acetylcholine