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Acta Biologica Hungarica

, Volume 55, Issue 1–4, pp 167–176 | Cite as

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

  • Ágnes VehovszkyEmail author
  • A. Szűcs
  • Henriette Szabó
  • Samantha Pitt
  • C. J. H. Elliott
Article

Abstract

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.

Keywords

Lymnaea octopamine modulation membrane current voltage clamp 

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© Akadémiai Kiadó, Budapest 2004

This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made.

Authors and Affiliations

  • Ágnes Vehovszky
    • 1
    Email author
  • A. Szűcs
    • 1
  • Henriette Szabó
    • 1
  • Samantha Pitt
    • 3
  • C. J. H. Elliott
    • 2
  1. 1.Department of Experimental Zoology, Balaton Limnological Research InstituteHungarian Academy of SciencesTihanyHungary
  2. 2.Department of BiologyUniversity of YorkYorkEngland
  3. 3.Department of PhysiologyUniversity of CambridgeCambridgeEngland

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