Neuromodulation of flight initiation by octopamine in the cockroach Periplaneta americana

A. Weisel-Eichler, F. Libersat

Research output: Contribution to journalArticlepeer-review

24 Scopus citations

Abstract

We have tested the effect of a known insect neuromodulator, octopamine, on flight initiation in the cockroach. Using minimally dissected animals, we found that octopamine lowered the threshold for wind-evoked initiation of flight when applied to either of two major synaptic sites in the flight circuitry: 1) the last abdominal ganglion, where wind-sensitive neurons from the cerci excite dorsal giant interneurons, or 2) the metathoracic ganglion, where the dorsal giant interneurons activate interneurons and motoneurons which are involved in producing the rhythmic flight motor pattern in the flight muscles (Fig. 2). Correlated with this change in flight initiation threshold, we found that octopamine applied to the last abdominal ganglion increased the number of action potentials produced by individual dorsal giant interneurons when recruiting the cercal wind-sensitive neurons with wind puffs (Figs. 3, 4, 5) or with extracellular stimulation of their axons (Fig. 6). Octopamine increases the excitability of the giant interneurons (Figs. 7, 8). Also, when we stimulated individual dorsal giant interneurons intracellularly, the number of action potentials needed to initiate flight was reduced when octopamine was applied to the metathoracic ganglion (Fig. 9).

Original languageEnglish
Pages (from-to)103-112
Number of pages10
JournalJournal of Comparative Physiology A: Neuroethology, Sensory, Neural, and Behavioral Physiology
Volume179
Issue number1
DOIs
StatePublished - 1 Jan 1996

Keywords

  • Behavioral initiation
  • Cockroach
  • Flight
  • Neuromodulation
  • Octopamine

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