Cellular mechanism of acetylcholine‐induced response in dissociated outer hair cells of guinea‐pig cochlea.

S. Kakehata, T. Nakagawa, T. Takasaka, N. Akaike

研究成果: ジャーナルへの寄稿記事

108 引用 (Scopus)

抄録

1. The acetylcholine (ACh)‐induced currents (IACh) in dissociated outer hair cells (OHCs) of guinea‐pig cochlea were investigated using the whole‐cell patch‐clamp technique, in both conventional and nystatin perforated‐patch configurations. 2. ACh and carbamylcholine (CCh) induced outward currents at a holding potential (VH) of ‐60 mV in the perforated‐patch configuration. The IACh increased in a sigmoidal fashion over the concentration range between 3 x 10(‐6) and 10(‐3) M. The dissociation constant (KD) was 1.7 x 10(‐5) M and the Hill coefficient (n) was 2.7. The KD and n for CCh were 8.7 x 10(‐5) M and 2.2, respectively. Neither nicotine nor muscarine induced any detectable current up to a concentration of 10(‐3) M. 3. Various muscarinic agonists such as oxotremorine‐M, McN‐A‐343 and oxotremorine could also induce the outward currents, although these current amplitudes were about one‐third that of ACh, indicating that they were partial agonists. 4. The muscarinic antagonists atropine, 4‐DAMP, AF‐DX 116 and pirenzepine inhibited the IACh in a concentration‐dependent manner. The half‐inhibitory concentrations (IC50) for atropine, 4‐DAMP, AF‐DX 116 and pirenzepine were 4.8 x 10(‐6), 6.2 x 10(‐6), 2.1 x 10(‐5) and 2.9 x 10(‐4) M, respectively. 5. When the extracellular Ca2+ concentration ([Ca2+])o) was reduced to lower than 1 mM, the amplitude of IACh, abruptly decreased. In a nominally Ca(2+)‐free external solution ACh did not induce any current. The increase of [Ca2+]o beyond 1 mM did not change the IACh. 6. When OHCs were perfused intracellularly with a pipette solution containing 10 mM BAPTA in the conventional whole‐cell mode, ACh could not induce outward K+ currents. The Ca2+ ionophore A23187 induced an outward current. These results indicate that intracellular Ca2+ is involved in the ACh response. 7. Calmodulin inhibitors such as chlorpromazine, W‐7 and trifluoperazine inhibited the IACh in a concentration‐dependent manner. 8. When OHCs were dialysed with either 100 microM GDP beta S or 1 micrograms/ml pertussis toxin (PTX) through the patch pipette at a VH of ‐60 mV, the IACh diminished within 10 min, whereas the IACh of the control remained steady for over 20 min, suggesting that a PTX‐sensitive G‐protein is involved in the ACh response.(ABSTRACT TRUNCATED AT 400 WORDS)

元の言語英語
ページ(範囲)227-244
ページ数18
ジャーナルThe Journal of Physiology
463
発行部数1
DOI
出版物ステータス出版済み - 4 1 1993

Fingerprint

Outer Auditory Hair Cells
Cochlea
Acetylcholine
Pirenzepine
Carbachol
Atropine
Muscarine
Oxotremorine
Nystatin
Trifluoperazine
Muscarinic Agonists
Muscarinic Antagonists
Ionophores
Pertussis Toxin
Chlorpromazine
Calcimycin
Calmodulin
Nicotine
Inhibitory Concentration 50

All Science Journal Classification (ASJC) codes

  • Physiology

これを引用

Cellular mechanism of acetylcholine‐induced response in dissociated outer hair cells of guinea‐pig cochlea. / Kakehata, S.; Nakagawa, T.; Takasaka, T.; Akaike, N.

:: The Journal of Physiology, 巻 463, 番号 1, 01.04.1993, p. 227-244.

研究成果: ジャーナルへの寄稿記事

@article{b6532e2ba69c40bf9a9e91406e2c68fb,
title = "Cellular mechanism of acetylcholine‐induced response in dissociated outer hair cells of guinea‐pig cochlea.",
abstract = "1. The acetylcholine (ACh)‐induced currents (IACh) in dissociated outer hair cells (OHCs) of guinea‐pig cochlea were investigated using the whole‐cell patch‐clamp technique, in both conventional and nystatin perforated‐patch configurations. 2. ACh and carbamylcholine (CCh) induced outward currents at a holding potential (VH) of ‐60 mV in the perforated‐patch configuration. The IACh increased in a sigmoidal fashion over the concentration range between 3 x 10(‐6) and 10(‐3) M. The dissociation constant (KD) was 1.7 x 10(‐5) M and the Hill coefficient (n) was 2.7. The KD and n for CCh were 8.7 x 10(‐5) M and 2.2, respectively. Neither nicotine nor muscarine induced any detectable current up to a concentration of 10(‐3) M. 3. Various muscarinic agonists such as oxotremorine‐M, McN‐A‐343 and oxotremorine could also induce the outward currents, although these current amplitudes were about one‐third that of ACh, indicating that they were partial agonists. 4. The muscarinic antagonists atropine, 4‐DAMP, AF‐DX 116 and pirenzepine inhibited the IACh in a concentration‐dependent manner. The half‐inhibitory concentrations (IC50) for atropine, 4‐DAMP, AF‐DX 116 and pirenzepine were 4.8 x 10(‐6), 6.2 x 10(‐6), 2.1 x 10(‐5) and 2.9 x 10(‐4) M, respectively. 5. When the extracellular Ca2+ concentration ([Ca2+])o) was reduced to lower than 1 mM, the amplitude of IACh, abruptly decreased. In a nominally Ca(2+)‐free external solution ACh did not induce any current. The increase of [Ca2+]o beyond 1 mM did not change the IACh. 6. When OHCs were perfused intracellularly with a pipette solution containing 10 mM BAPTA in the conventional whole‐cell mode, ACh could not induce outward K+ currents. The Ca2+ ionophore A23187 induced an outward current. These results indicate that intracellular Ca2+ is involved in the ACh response. 7. Calmodulin inhibitors such as chlorpromazine, W‐7 and trifluoperazine inhibited the IACh in a concentration‐dependent manner. 8. When OHCs were dialysed with either 100 microM GDP beta S or 1 micrograms/ml pertussis toxin (PTX) through the patch pipette at a VH of ‐60 mV, the IACh diminished within 10 min, whereas the IACh of the control remained steady for over 20 min, suggesting that a PTX‐sensitive G‐protein is involved in the ACh response.(ABSTRACT TRUNCATED AT 400 WORDS)",
author = "S. Kakehata and T. Nakagawa and T. Takasaka and N. Akaike",
year = "1993",
month = "4",
day = "1",
doi = "10.1113/jphysiol.1993.sp019592",
language = "English",
volume = "463",
pages = "227--244",
journal = "Journal of Physiology",
issn = "0022-3751",
publisher = "Wiley-Blackwell",
number = "1",

}

TY - JOUR

T1 - Cellular mechanism of acetylcholine‐induced response in dissociated outer hair cells of guinea‐pig cochlea.

AU - Kakehata, S.

AU - Nakagawa, T.

AU - Takasaka, T.

AU - Akaike, N.

PY - 1993/4/1

Y1 - 1993/4/1

N2 - 1. The acetylcholine (ACh)‐induced currents (IACh) in dissociated outer hair cells (OHCs) of guinea‐pig cochlea were investigated using the whole‐cell patch‐clamp technique, in both conventional and nystatin perforated‐patch configurations. 2. ACh and carbamylcholine (CCh) induced outward currents at a holding potential (VH) of ‐60 mV in the perforated‐patch configuration. The IACh increased in a sigmoidal fashion over the concentration range between 3 x 10(‐6) and 10(‐3) M. The dissociation constant (KD) was 1.7 x 10(‐5) M and the Hill coefficient (n) was 2.7. The KD and n for CCh were 8.7 x 10(‐5) M and 2.2, respectively. Neither nicotine nor muscarine induced any detectable current up to a concentration of 10(‐3) M. 3. Various muscarinic agonists such as oxotremorine‐M, McN‐A‐343 and oxotremorine could also induce the outward currents, although these current amplitudes were about one‐third that of ACh, indicating that they were partial agonists. 4. The muscarinic antagonists atropine, 4‐DAMP, AF‐DX 116 and pirenzepine inhibited the IACh in a concentration‐dependent manner. The half‐inhibitory concentrations (IC50) for atropine, 4‐DAMP, AF‐DX 116 and pirenzepine were 4.8 x 10(‐6), 6.2 x 10(‐6), 2.1 x 10(‐5) and 2.9 x 10(‐4) M, respectively. 5. When the extracellular Ca2+ concentration ([Ca2+])o) was reduced to lower than 1 mM, the amplitude of IACh, abruptly decreased. In a nominally Ca(2+)‐free external solution ACh did not induce any current. The increase of [Ca2+]o beyond 1 mM did not change the IACh. 6. When OHCs were perfused intracellularly with a pipette solution containing 10 mM BAPTA in the conventional whole‐cell mode, ACh could not induce outward K+ currents. The Ca2+ ionophore A23187 induced an outward current. These results indicate that intracellular Ca2+ is involved in the ACh response. 7. Calmodulin inhibitors such as chlorpromazine, W‐7 and trifluoperazine inhibited the IACh in a concentration‐dependent manner. 8. When OHCs were dialysed with either 100 microM GDP beta S or 1 micrograms/ml pertussis toxin (PTX) through the patch pipette at a VH of ‐60 mV, the IACh diminished within 10 min, whereas the IACh of the control remained steady for over 20 min, suggesting that a PTX‐sensitive G‐protein is involved in the ACh response.(ABSTRACT TRUNCATED AT 400 WORDS)

AB - 1. The acetylcholine (ACh)‐induced currents (IACh) in dissociated outer hair cells (OHCs) of guinea‐pig cochlea were investigated using the whole‐cell patch‐clamp technique, in both conventional and nystatin perforated‐patch configurations. 2. ACh and carbamylcholine (CCh) induced outward currents at a holding potential (VH) of ‐60 mV in the perforated‐patch configuration. The IACh increased in a sigmoidal fashion over the concentration range between 3 x 10(‐6) and 10(‐3) M. The dissociation constant (KD) was 1.7 x 10(‐5) M and the Hill coefficient (n) was 2.7. The KD and n for CCh were 8.7 x 10(‐5) M and 2.2, respectively. Neither nicotine nor muscarine induced any detectable current up to a concentration of 10(‐3) M. 3. Various muscarinic agonists such as oxotremorine‐M, McN‐A‐343 and oxotremorine could also induce the outward currents, although these current amplitudes were about one‐third that of ACh, indicating that they were partial agonists. 4. The muscarinic antagonists atropine, 4‐DAMP, AF‐DX 116 and pirenzepine inhibited the IACh in a concentration‐dependent manner. The half‐inhibitory concentrations (IC50) for atropine, 4‐DAMP, AF‐DX 116 and pirenzepine were 4.8 x 10(‐6), 6.2 x 10(‐6), 2.1 x 10(‐5) and 2.9 x 10(‐4) M, respectively. 5. When the extracellular Ca2+ concentration ([Ca2+])o) was reduced to lower than 1 mM, the amplitude of IACh, abruptly decreased. In a nominally Ca(2+)‐free external solution ACh did not induce any current. The increase of [Ca2+]o beyond 1 mM did not change the IACh. 6. When OHCs were perfused intracellularly with a pipette solution containing 10 mM BAPTA in the conventional whole‐cell mode, ACh could not induce outward K+ currents. The Ca2+ ionophore A23187 induced an outward current. These results indicate that intracellular Ca2+ is involved in the ACh response. 7. Calmodulin inhibitors such as chlorpromazine, W‐7 and trifluoperazine inhibited the IACh in a concentration‐dependent manner. 8. When OHCs were dialysed with either 100 microM GDP beta S or 1 micrograms/ml pertussis toxin (PTX) through the patch pipette at a VH of ‐60 mV, the IACh diminished within 10 min, whereas the IACh of the control remained steady for over 20 min, suggesting that a PTX‐sensitive G‐protein is involved in the ACh response.(ABSTRACT TRUNCATED AT 400 WORDS)

UR - http://www.scopus.com/inward/record.url?scp=0027538406&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0027538406&partnerID=8YFLogxK

U2 - 10.1113/jphysiol.1993.sp019592

DO - 10.1113/jphysiol.1993.sp019592

M3 - Article

C2 - 7504105

AN - SCOPUS:0027538406

VL - 463

SP - 227

EP - 244

JO - Journal of Physiology

JF - Journal of Physiology

SN - 0022-3751

IS - 1

ER -