Skip to main content
NCBI home page
The Journal of Physiology logoLink to The Journal of Physiology
. 1991 Oct;442:669–690. doi: 10.1113/jphysiol.1991.sp018814

Muscarinic receptor hyperpolarizes cochlear hair cells of chick by activating Ca(2+)-activated K+ channels.

T Shigemoto 1, H Ohmori 1
PMCID: PMC1179910  PMID: 1798048

Abstract

1. Electrical responses to extracellularly applied acetylcholine (ACh) and to intracellularly introduced substances were studied in isolated short and tall hair cells from the chick cochlear organ by a whole-cell voltage clamp technique using a patch electrode. These cells were isolated without using proteolytic enzymes. 2. Short hair cells generated a transient outward current at -50 mV in normal saline in response to puff-applied 100 microM-ACh, when the patch electrode was filled with a 160 mM-K+ and 100 microM-EGTA-based intracellular medium. The amplitude was 317.1 +/- 97.1 pA (n = 32). When ACh was applied ionophoretically, the outward current was generated with a delay of about 10 ms. 3. The amplitude of ACh-induced current was dose dependent with a KD of 19 microM and a Hill coefficient of 1.6 when measured at -50 mV. 4. The ACh (100 microM)-induced current was suppressed by 1 microM-atropine. ACh-induced current was generated in a Ca(2+)-free extracellular medium; however, the second ACh puff in the Ca(2+)-free medium generated a much reduced response. ACh-induced current was suppressed reversibly by 100 microM-quinine. 5. Intracellular injections of guanosine-5'-O-(3-thiotriphosphate) (GTP gamma S), inositol 1,4,5-trisphosphate (IP3) or Ca2+ (1 microM) via the patch pipette activated outward currents at -50 mV. 6. When the internal medium with strong Ca(2+)-buffering capacity (5 mM-EGTA) was used, the ACh-induced current was reduced to 39.3 +/- 6.8 pA (n = 4) at -50 mV (12.3% of the response in the low-EGTA medium). 7. The reversal potential of the ACh-induced current was -85.7 +/- 4.2 mV (n = 3) in normal saline containing 5 mM-K+. The reversal potential was dependent on the extracellular K+ concentration ([K+]o) and was shifted 57 mV by a 10-fold increase in [K+]o at room temperature (20-25 degrees C). 8. These results (points 4-7) indicate that ACh induces a K+ conductance by releasing Ca2+ intracellularly, probably by activating the pathway of muscarine receptor, G-protein and IP3. 9. Channel activities were recorded using cell-attached patch electrodes. Channel activities were rarely observed when ACh was applied to the extra-patch membrane, while robust channel activities were observed when ACh was included in the patch pipette medium. It is therefore suggested that Ca(2+)-activated K+ channels exist in the membrane in close vicinity to muscarinic receptor molecules and intracellular Ca2+ release sites.(ABSTRACT TRUNCATED AT 400 WORDS)

Full text

PDF
669

Images in this article

671Fig. 1
on p.671

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Art J. J., Fettiplace R., Fuchs P. A. Synaptic hyperpolarization and inhibition of turtle cochlear hair cells. J Physiol. 1984 Nov;356:525–550. doi: 10.1113/jphysiol.1984.sp015481. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Barrett J. N., Magleby K. L., Pallotta B. S. Properties of single calcium-activated potassium channels in cultured rat muscle. J Physiol. 1982 Oct;331:211–230. doi: 10.1113/jphysiol.1982.sp014370. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Baylor D. A., Fuortes M. G. Electrical responses of single cones in the retina of the turtle. J Physiol. 1970 Mar;207(1):77–92. doi: 10.1113/jphysiol.1970.sp009049. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Baylor D. A., Hodgkin A. L., Lamb T. D. The electrical response of turtle cones to flashes and steps of light. J Physiol. 1974 Nov;242(3):685–727. doi: 10.1113/jphysiol.1974.sp010731. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Berridge M. J., Irvine R. F. Inositol trisphosphate, a novel second messenger in cellular signal transduction. Nature. 1984 Nov 22;312(5992):315–321. doi: 10.1038/312315a0. [DOI] [PubMed] [Google Scholar]
  6. Blatz A. L., Magleby K. L. Single apamin-blocked Ca-activated K+ channels of small conductance in cultured rat skeletal muscle. Nature. 1986 Oct 23;323(6090):718–720. doi: 10.1038/323718a0. [DOI] [PubMed] [Google Scholar]
  7. Cockcroft S., Gomperts B. D. Role of guanine nucleotide binding protein in the activation of polyphosphoinositide phosphodiesterase. Nature. 1985 Apr 11;314(6011):534–536. doi: 10.1038/314534a0. [DOI] [PubMed] [Google Scholar]
  8. Cook N. S., Haylett D. G. Effects of apamin, quinine and neuromuscular blockers on calcium-activated potassium channels in guinea-pig hepatocytes. J Physiol. 1985 Jan;358:373–394. doi: 10.1113/jphysiol.1985.sp015556. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Delaney K. R., Zucker R. S. Calcium released by photolysis of DM-nitrophen stimulates transmitter release at squid giant synapse. J Physiol. 1990 Jul;426:473–498. doi: 10.1113/jphysiol.1990.sp018150. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. DiFrancesco D., Ducouret P., Robinson R. B. Muscarinic modulation of cardiac rate at low acetylcholine concentrations. Science. 1989 Feb 3;243(4891):669–671. doi: 10.1126/science.2916119. [DOI] [PubMed] [Google Scholar]
  11. Dun N. J., Kaibara K., Karczmar A. G. Muscarinic and cGMP induced membrane potential changes: differences in electrogenic mechanisms. Brain Res. 1978 Jul 21;150(3):658–661. doi: 10.1016/0006-8993(78)90833-8. [DOI] [PubMed] [Google Scholar]
  12. Dworkin M., Keller K. H. Solubility and diffusion coefficient of adenosine 3':5'-monophosphate. J Biol Chem. 1977 Feb 10;252(3):864–865. [PubMed] [Google Scholar]
  13. Evans M. G., Marty A. Potentiation of muscarinic and alpha-adrenergic responses by an analogue of guanosine 5'-triphosphate. Proc Natl Acad Sci U S A. 1986 Jun;83(11):4099–4103. doi: 10.1073/pnas.83.11.4099. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Fabiato A., Fabiato F. Calculator programs for computing the composition of the solutions containing multiple metals and ligands used for experiments in skinned muscle cells. J Physiol (Paris) 1979;75(5):463–505. [PubMed] [Google Scholar]
  15. Fenwick E. M., Marty A., Neher E. Sodium and calcium channels in bovine chromaffin cells. J Physiol. 1982 Oct;331:599–635. doi: 10.1113/jphysiol.1982.sp014394. [DOI] [PMC free article] [PubMed] [Google Scholar]
  16. Flock A., Flock B., Ulfendahl M. Mechanisms of movement in outer hair cells and a possible structural basis. Arch Otorhinolaryngol. 1986;243(2):83–90. doi: 10.1007/BF00453755. [DOI] [PubMed] [Google Scholar]
  17. Fukuda K., Higashida H., Kubo T., Maeda A., Akiba I., Bujo H., Mishina M., Numa S. Selective coupling with K+ currents of muscarinic acetylcholine receptor subtypes in NG108-15 cells. Nature. 1988 Sep 22;335(6188):355–358. doi: 10.1038/335355a0. [DOI] [PubMed] [Google Scholar]
  18. Furukawa T. Effects of efferent stimulation on the saccule of goldfish. J Physiol. 1981 Jun;315:203–215. doi: 10.1113/jphysiol.1981.sp013742. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Gallacher D. V., Morris A. P. The receptor-regulated calcium influx in mouse submandibular acinar cells is sodium dependent: a patch-clamp study. J Physiol. 1987 Mar;384:119–130. doi: 10.1113/jphysiol.1987.sp016446. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Guth P. S., Norris C. H., Bobbin R. P. The pharmacology of transmission in the peripheral auditory system. Pharmacol Rev. 1976 Jun;28(2):95–125. [PubMed] [Google Scholar]
  21. Horn R., Marty A. Muscarinic activation of ionic currents measured by a new whole-cell recording method. J Gen Physiol. 1988 Aug;92(2):145–159. doi: 10.1085/jgp.92.2.145. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Kaneko A., Tachibana M. Effects of gamma-aminobutyric acid on isolated cone photoreceptors of the turtle retina. J Physiol. 1986 Apr;373:443–461. doi: 10.1113/jphysiol.1986.sp016057. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Katz B., Miledi R. Tetrodotoxin-resistant electric activity in presynaptic terminals. J Physiol. 1969 Aug;203(2):459–487. doi: 10.1113/jphysiol.1969.sp008875. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Katz B., Miledi R. The timing of calcium action during neuromuscular transmission. J Physiol. 1967 Apr;189(3):535–544. doi: 10.1113/jphysiol.1967.sp008183. [DOI] [PMC free article] [PubMed] [Google Scholar]
  25. Kwok-Keung Fung B., Stryer L. Photolyzed rhodopsin catalyzes the exchange of GTP for bound GDP in retinal rod outer segments. Proc Natl Acad Sci U S A. 1980 May;77(5):2500–2504. doi: 10.1073/pnas.77.5.2500. [DOI] [PMC free article] [PubMed] [Google Scholar]
  26. Marty A. Ca-dependent K channels with large unitary conductance in chromaffin cell membranes. Nature. 1981 Jun 11;291(5815):497–500. doi: 10.1038/291497a0. [DOI] [PubMed] [Google Scholar]
  27. Nargeot J., Nerbonne J. M., Engels J., Lester H. A. Time course of the increase in the myocardial slow inward current after a photochemically generated concentration jump of intracellular cAMP. Proc Natl Acad Sci U S A. 1983 Apr;80(8):2395–2399. doi: 10.1073/pnas.80.8.2395. [DOI] [PMC free article] [PubMed] [Google Scholar]
  28. Ohmori H. Mechano-electrical transduction currents in isolated vestibular hair cells of the chick. J Physiol. 1985 Feb;359:189–217. doi: 10.1113/jphysiol.1985.sp015581. [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. Ohmori H. Studies of ionic currents in the isolated vestibular hair cell of the chick. J Physiol. 1984 May;350:561–581. doi: 10.1113/jphysiol.1984.sp015218. [DOI] [PMC free article] [PubMed] [Google Scholar]
  30. Pallotta B. S., Magleby K. L., Barrett J. N. Single channel recordings of Ca2+-activated K+ currents in rat muscle cell culture. Nature. 1981 Oct 8;293(5832):471–474. doi: 10.1038/293471a0. [DOI] [PubMed] [Google Scholar]
  31. Petersen O. H. Calcium-activated potassium channels and fluid secretion by exocrine glands. Am J Physiol. 1986 Jul;251(1 Pt 1):G1–13. doi: 10.1152/ajpgi.1986.251.1.G1. [DOI] [PubMed] [Google Scholar]
  32. Shigemoto T., Ohmori H. Muscarinic agonists and ATP increase the intracellular Ca2+ concentration in chick cochlear hair cells. J Physiol. 1990 Jan;420:127–148. doi: 10.1113/jphysiol.1990.sp017904. [DOI] [PMC free article] [PubMed] [Google Scholar]
  33. Takasaka T., Smith C. A. The structure and innervation of the pigeon's basilar papilla. J Ultrastruct Res. 1971 Apr;35(1):20–65. doi: 10.1016/s0022-5320(71)80141-7. [DOI] [PubMed] [Google Scholar]
  34. Tanaka K., Smith C. A. Structure of the chicken's inner ear: SEM and TEM study. Am J Anat. 1978 Oct;153(2):251–271. doi: 10.1002/aja.1001530206. [DOI] [PubMed] [Google Scholar]

Articles from The Journal of Physiology are provided here courtesy of The Physiological Society

RESOURCES