Respiratory nervous activity in the isolated nerve cord of the larval dragonfly, and location of the respiratory oscillator

Abstract

Rhythmic respiratory nerve activity was recorded in the dragonfly larvae, Anax parthenope julius Brauer (Anisoptera). Alternating expiratory and inspiratory bursts of spikes occurred in abdominal nerve cords isolated from all peripheral connections. These bursts are similar to the activity recorded in semiintact preparations, suggesting that the respiratory rhythm can be generated without peripheral sensory feedback. Expiratory bursts started and ended at the same time in different segments of semi-intact preparations. When connectives were severed, the nerve cord separated from the last abdominal ganglion did not normally show rhythmic bursts; the last ganglion alone and the nerve cord connected to the last ganglion exhibited the rhythmic bursts. However, in a few cases the nerve cord separated from the last ganglion exhibited the rhythm. The results suggest that the last ganglion contains the main oscillator, but that other weak oscillators occur elsewhere.

Patterns of intermittent ventilation and responses to perfusing gas mixtures in quiescent Blaberus craniifer

“…As an introduction to the study of a slow rhythm, we present here some data on intermittent ventilation in a large cockroach and we describe some of its responses to hypoxia and hypercapnia. Recent work on insect ventilation has concentrated mainly on its neural origin and on the co-ordination of spiracle and pumping movements (Burrows, 1974;Pearson, 1980;Komatsu, 1982;Fitch & Kammer, 1983;Kinnamon & Kammer, 1983;Kaars, 1983;Yang & Burrows, 1983), while longerterm aspects of its patterning have been neglected.…”

Ventilatorische Rhythmogenese im isolierten Insektennervensystem

“…bei Ameisen (Lighton, 1990;Lighton und Berrigan, 1994;Quinlan und Lighton, 1999), Feldheuschrecken (Harrison et al, 1995;Lange et al 2000), Honigbienen (Lighton und Lovegrove, 1990), Laufkäfern (Punt et al, 1957), Schaben (Kestler et al, 2000) und bei anderen Insektenspezies (Kestler, 1984). Die endogene Aktivität des durch die afferente Rückkopplung ungestörten CPGs ist nie intensiver betrachtet worden (aber siehe: Case, 1961;Komatsu, 1982).…”

“…Abbildung 7, bei Taeniopoda eques). Frühe Untersuchungen zu efferenten ventilatorischen Mustern von Insekten zeigten lediglich regelmäßige neurale Entladungen(Case 1961, Miller 1960, Komatsu 1982 in Kurzzeitaufnahmen ohne diskontinuierliche Atmung. Eine nähereBetrachtung von Millers Daten (1961) in ruhenden Wüstenheuschrecken (Schistocerca gregaria) zeigen jedoch auch diskontinuierliche Atmungsmuster an Schnitten (slices) von Insektenganglionen (Schistocerca gregaria) die Erhaltung von Atemrhythmen in isolierten Präparaten gezeigt werden(Ramirez et al, 1999).Bei Säugern ist seit längerer Zeit bekannt, daß im isolierten Hirnstamm in vitro neuronale Entladungen ventilatorischer Art für viele Stunden erzeugt werden.…”