Octopamine boosts snail locomotion: behavioural and cellular analysis

Invert Neurosci. 2006 Dec;6(4):215-20. doi: 10.1007/s10158-006-0031-1. Epub 2006 Oct 28.

Abstract

We measured the reduction in locomotion of unrestrained pond snails, Lymnaea stagnalis, subsequent to transdermal application of two selective octopamine antagonists, epinastine and phentolamine. After 3 h in fresh standard snail water following treatment with 4 mM epinastine or 3.5 mM phentolamine, the snails' speed was reduced to 25 and 56% of the controls (P < 0.001 and P = 0.02, respectively). The snails' speed decreased as the drug concentration increased. In the isolated CNS, 0.5 mM octopamine increased the firing rate of the pedal A cluster motoneurons, which innervate the cilia of the foot. In normal saline the increase was 26% and in a high magnesium/low calcium saline 22% (P < 0.05 and 0.01, respectively). We conclude that octopamine is likely to modulate snail locomotion, partially through effects on pedal motoneurons.

MeSH terms

  • Adrenergic alpha-Agonists / metabolism*
  • Adrenergic alpha-Antagonists / pharmacology
  • Animals
  • Behavior, Animal / physiology*
  • Dibenzazepines / pharmacology
  • Histamine H1 Antagonists / pharmacology
  • Imidazoles / pharmacology
  • Motor Activity / physiology*
  • Motor Neurons / metabolism*
  • Octopamine / metabolism*
  • Phentolamine / pharmacology
  • Snails / physiology*

Substances

  • Adrenergic alpha-Agonists
  • Adrenergic alpha-Antagonists
  • Dibenzazepines
  • Histamine H1 Antagonists
  • Imidazoles
  • Octopamine
  • epinastine
  • Phentolamine