Pflügers Archiv - European Journal of Physiology

, Volume 413, Issue 3, pp 249–255 | Cite as

Ion permeation through hyperpolarization-activated membrane channels (Q-channels) in the lobster stretch receptor neurone

  • Å. Edman
  • W. Grampp
Excitable Tissues Cand Central Nervous Physiology


In the lobster stretch receptor neurone it is possible to demonstrate a hyperpolarization-activated membrane current,IQ, which appears to be carried by Na+ and K+ in combination. The ion permeability of the membrane channel conducting this current (Q-channel) was investigated using conventional electrophysiological techniques including intracellular ion concentration measurements. It was found that none of the ions choline, protonated Tris, Rb+, NH 4 + , Li+, and protonated hydroxylamine was able to pass through theQ-channel which, thus, appears to be permeable to Na+ and K+ only. With increasing extracellular Na+ concentrations,IQ was increased up to a saturation level. This behaviour could be described by a one-site-two-barriers version of the Eyring rate theory, assuming that the permeant ions are turned over at specific saturable channel sites which ‘sense’ 70% of the transmembrane potential difference. With increasing extracellular K+ concentrations,IQ was increased in accordance with a simple first-order doseresponse relationship. This finding can be accounted for by assuming that K+ increases all rates of turn-over of the permeant ions at their specific sites by similar relative amounts. Changes in extracellular Na+ and K+ concentrations were found to have no effect on the gating properties of theQ-channel.

Key words

Ion permeation Ion channel Anomalous rectification Stretch receptor 


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  1. Bader CR, Bertrand D (1984) Effect of changes in intra- and extracellular sodium on the inward (anomalous) rectification in salamander photoreceptors. J Physiol 347:611–631CrossRefPubMedPubMedCentralGoogle Scholar
  2. Chandler WK, Meves H (1965) Voltage-clamp experiments on internally perfused giant axons. J Physiol 180:788–820CrossRefPubMedPubMedCentralGoogle Scholar
  3. Constanti A, Galvan M (1983) Fast inward-rectifying current accounts for anomalous rectification in olfactory cortex neurones. J Physiol 385:153–178CrossRefGoogle Scholar
  4. DiFrancesco D (1982) Block and activation of the pace-maker channel in calf Purkinje fibres: effects of potassium, caesium and rubidium. J Physiol 329:485–507CrossRefPubMedPubMedCentralGoogle Scholar
  5. DiFrancesco D, Ferroni A, Mazzanti M, Tromba C (1986) Properties of the hyperpolarizing-activated current (i f) in cells isolated from the rabbit sino-atrial node. J Physiol 377:61–88CrossRefPubMedPubMedCentralGoogle Scholar
  6. Edman Å, Grampp W (1987) A hyperpolarization-activated membrane current in isolated lobster stretch receptor neurones. J Physiol 390:228PGoogle Scholar
  7. Edman Å, Gestrelius S, Grampp W (1986) Transmembrane ion balance in slowly and rapidly adapting lobster stretch receptor neurones. J Physiol 377:171–191CrossRefPubMedPubMedCentralGoogle Scholar
  8. Edman Å, Gestrelius S, Grampp W (1987) Current activation by membrane hyperpolarization in the slowly adapting lobster stretch receptor neurone. J Physiol 384:671–690CrossRefPubMedPubMedCentralGoogle Scholar
  9. Hagiwara S, Takahashi K (1974) The anomalous rectification and cation selectivity of the membrane of the starfish egg cell. J Membr Biol 18:61–80CrossRefPubMedGoogle Scholar
  10. Hagiwara S, Eaton DC, Stuart AE, Rosenthal NP (1972) Cation selectivity of the resting membrane of squid axon. J Membr Biol 9:373–384CrossRefGoogle Scholar
  11. Halliwell JV, Adams PR (1982) Voltage-clamp analysis of muscarinic excitation in hippocampal neurones. Brain Res 250:71–92CrossRefPubMedGoogle Scholar
  12. Hille B (1971) The permeability of the sodium channel to organic cations in myelinated nerve. J Gen Physiol 58:599–619CrossRefPubMedPubMedCentralGoogle Scholar
  13. Hille B (1972) The permeability of the sodium channel to metal cations in myelinated nerve. J Gen Physiol 59:637–658CrossRefPubMedPubMedCentralGoogle Scholar
  14. Hille B (1973) Potassium channels in myelinated nerve. Selective permeability to small cations. J Gen Physiol 61:669–686CrossRefPubMedPubMedCentralGoogle Scholar
  15. Hille B (1975) Ion selectivity of Na and K channels of nerve membranes. In: Eisenman G (ed) Membranes: a series of advances. Dekker, New York Basel, p 255Google Scholar
  16. Lakshminarayanaiah N (1984) Equations of membrane biophysics. Academic Press, London New YorkGoogle Scholar
  17. Leech CA, Stanfield PR (1981) Inward rectification in frog skeletal muscle fibres and its dependence on membrane potential and external potassium. J Physiol 319:295–309CrossRefPubMedPubMedCentralGoogle Scholar
  18. Mayer ML, Westbrook GL (1983) A voltage-clamp analysis of inward (anomalous) rectification in mouse spinal sensory ganglion neurones. J Physiol 340:19–45CrossRefPubMedPubMedCentralGoogle Scholar

Copyright information

© Springer-Verlag 1989

Authors and Affiliations

  • Å. Edman
    • 1
  • W. Grampp
    • 1
  1. 1.Department of Physiology and BiophysicsUniversity of LundLundSweden

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