Octopaminergic Modulation of the Membrane Currents in the Central Feeding System of the Pond Snail Lymnaea Stagnalis


Octopamine is released by the intrinsic OC interneurons in the paired buccal ganglia and serves both as a. neurotransmitter and a. neuromodulator in the central feeding network of the pond snail Lymnaea stag-nalis [19].

The identified Bl buccal motoneuron receives excitatory inputs from the OC interneurons and is more excitable in the presence of 10 |lM octopamine in the bath. This modulatory effect of octopamine on the B1 motoneuron was studied using the two electrode voltage clamp method.

In normal physiological saline depolarising voltage steps from the holding potential of-80 mV evoke a. transient inward current, presumably carried by Na+ ions. The peak values of this inward current are increased in the presence of 10 |lM octopamine in the bath. In contrast, both the transient (IA) and delayed (IK) outward currents are unaffected by octopamine application.

Replacing the normal saline with aNa+-free bathing solution containing K+ channel blockers (50 mM TEAC1, 4 mM 4AP) revealed the presence of an additional inward current of the Bl neurons, carried by Ca2+. Octopamine (10 |lM) in the bath decreased the amplitudes of this current.

These results suggest that the membrane mechanisms which underlie the modulatory effect of octopamine on the Bl motoneuron include selective changes of the Na+- and Ca2+-channels.


  1. 1.

    Acosta-Urquidi, J. (1988) Modulation of Calcium current and diverse K+ currents in identified Hermissenda neurons by small cardioactive peptide B. J. Neurosci. 8, 1694–1703.

    CAS  Article  Google Scholar 

  2. 2.

    Adams, W. B., Benson, J. A. (1985) The generation and modulation of endogenous rhythmicity in the Aplysia bursting pacemaker neurone R15 Progr. Biophys. Molec. Biol. 46, 1—49.

  3. 3.

    Barnes, S., Syed, N. I., Bulloch, A. G. M. (1994) Modulation of ionic currents by dopamine in an interneuron of the respiratory central pattern generator of Lymnaea stagnalis. J. exp. Biol. 189, 37–54.

    CAS  PubMed  Google Scholar 

  4. 4.

    Baxter, D. A., Byrne, J. H. (1989) Serotonergic modulation of two potassium currents in pleural sensory neurons in Aplysia. J. Neurophysiol. 62, 665–679.

    CAS  Article  Google Scholar 

  5. 5.

    Connor, J. A., Stevens, C. F. (1971) Inward and delayed outward membrane currents in isolated neuronal somata under voltage clamp. J. Physiol. 213, 1–19.

    CAS  Article  Google Scholar 

  6. 6.

    Connor, J. A., Stevens, C. F. (1971) Voltage clamp studies of a. transient outward membrane current in gastropod neural somata. J. Physiol. 213, 21–30.

    CAS  Article  Google Scholar 

  7. 7.

    Elliott, C. J. H., Kits, K. S., Lodder, J. C. (1997) Calcium currents in the buccal motoneurons of the pond snail, Lymnaea stagnalis. J. Physiol. 504P, P16.

    Google Scholar 

  8. 8.

    Elliott, C. J. H., Vehovszky, A. (2000) Polycyclic neuromodulation of the feeding rhythm of the pond snail Lymnaea stagnalis by the intrinsic octopaminergic interneuron, OC. Brain Res. 887, 63–69.

    CAS  Article  Google Scholar 

  9. 9.

    Hill-Venning, C., Cottrell, G. A. (1992) modulation of voltage-dependent calcium current in Helix aspersa buccal neurones by serotonin. Exp. Physiol. 77, 891–901.

    CAS  Article  Google Scholar 

  10. 10.

    Hodgkin, A. L., Huxley, A. F. (1952) Currents carried by sodium and potassium ions through the membrane of the giant axon of Loligo. J. Physiol. 116, 449–472.

    CAS  Article  Google Scholar 

  11. 11.

    Kits, K. S., Mansvelder, H. D. (1996) Voltage gated calcium channels in mollusc: classification Ca2+ dependent inactivation, modulation and functional roles. Invertebrate Neuroscience 2, 9–34.

    CAS  Article  Google Scholar 

  12. 12.

    Pitt, S., Vehovszky, A., Szabo, H., Elliott, C. J. H. (2004) Second messengers of octopamine receptors in the snail Lymnaea. Acta Biol. Hung. 55, 177–183 (this volume).

    CAS  Article  Google Scholar 

  13. 13.

    Rose, R. M., Benjamin, P. R. (1979) The relationship of the central motor pattern to the feeding cycle of Lymnaea stagnalis. J. Exp. Biol. 80, 137–163.

    CAS  PubMed  Google Scholar 

  14. 14.

    Rudy, B. (1988) Diversity and ubiquity of K. channels. Neuroscience 25, 727–749.

    Article  Google Scholar 

  15. 15.

    Soest, P. F., Kits, K. S. (1998) Conopressin affects excitability, firing, and action potential shape through stimulation of transient and persistent inward currents in molluscan neurons. J. Neuro-physiol. 79, 1619–1632.

    Google Scholar 

  16. 16.

    Stark, L. L., Mercer, A. R., Emptage, N. J., Carew, T. J. (1996) Pharmacological and kinetic characterization of two functional classes of serotonergic modulation in Aplysia sensory neurons. J. Neurophysiol. 75, 855–866.

    CAS  Article  Google Scholar 

  17. 17.

    Thompson, S. H. (1977) Three pharmacologically distinct potassium channels in molluscan neurones. J. Physiol. 265, 465–488.

    CAS  Article  Google Scholar 

  18. 18.

    Vehovszky, A., Elliott, C. J. H. (2002) Heterosynaptic modulation by the octopaminergic OC interneurons increases the synaptic outputs of protraction phase interneurons (SO, NIL) in the feeding system of Lymnaea stagnalis. Neuroscience 115, 483–494.

    CAS  Article  Google Scholar 

  19. 19.

    Vehovszky, A., Elliott, C. J. H. (2001) Activation and reconfiguration of Active feeding by the octopamine-containing modulatory OC interneurons in the pond snail Lymnaea stagnalis J. Neurophysiol. 86, 792–808.

    CAS  Article  Google Scholar 

  20. 20.

    Vehovszky, A., Hiripi, L., Elliott, C. J. H. (2000) Octopamine is the synaptic transmitter between identified neurons in the buccal feeding network of the pond snail Lymnaea stagnalis. Brain Res. 867, 188–199.

    CAS  Article  Google Scholar 

  21. 21.

    Wang, R., Pang, P. K., Wu, L., Shipley, A., Karpinski, E., Harvey, S., Berdan, R. C. (1993) Neural effects of parathyroid hormone: modulation of the calcium channel current and metabolism of monoamines in identified Helisoma snail neurons. Can. J. Physiol. Pharmacol. 71, 582–591.

    CAS  Article  Google Scholar 

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Correspondence to Ágnes Vehovszky.

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Presented at the 10th ISIN Symposium on Invertebrate Neurobiology, July 1–5, 2003, Tihany, Hungary.

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Vehovszky, Á., Szűcs, A., Szabó, H. et al. Octopaminergic Modulation of the Membrane Currents in the Central Feeding System of the Pond Snail Lymnaea Stagnalis. BIOLOGIA FUTURA 55, 167–176 (2004). https://doi.org/10.1556/ABiol.55.2004.1-4.21

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  • Lymnaea
  • octopamine
  • modulation
  • membrane current
  • voltage clamp