Octopamine immunoreactive cell populations in the locust thoracic-abdominal nervous system.
We describe octopamine-immunoreactive somata and their projections in the pro- meso-, meta- and pregenital abdominal-ganglia of locusts. Immunoreactive midline somata were identified as dorsal- and ventral- unpaired median (DUM- and VUM-, respectively) neurones due to their: characteristic large size and positions of somata, primary neurites in DUM-tracts giving rise to T-junctions, and bilaterally projecting axons. In the prothoracic ganglion there are most likely 8 such cells; in the meso- and metathoracic, some 20 each; and in each individual pregenital abdominal ganglion, typically 3. All appear to project to peripheral nerves and their numbers correspond to the number of peripherally projecting DUM-cells identified to date in each ganglion. We suggest that probably all peripherally projecting DUM-cells are octopaminergic in the examined ganglia. Presumptive DUM-interneurones are not octopamine-immunoreactive, but, confirming other studies, are shown to label with an antiserum to gamma-amino butyric acid (GABA). Other octopamine-immunoreactive neurones include a pair of midline, prothoracic, anterior medial cells, not necessarily DUM-cells, and a pair of ventral lateral somata in each thoracic- and the first abdominal ganglion. The latter project intersegmentally in ventral tracts. Intersegmentally projecting octopamine-immunoreactive fibers in dorsal tracts probably arise from a prothoracic DUM-cell, which leaves through suboesophageal nerves, or descending suboesophageal DUM-cells. Thus, the octopamine-immunoreactive system of thoracic and pregenital abdominal ganglia in locust comprises all peripherally projecting DUM-cells and a plurisegmental network.
Freie Universität Berlin, Institut für Neurobiologie, Federal Republic of Germany.
P A
PA
Stevenson
H J
HJ
Pflüger
M
M
Eckert
J
J
Rapus
D000005:Abdomen / Q000294:innervation*; D000818:Animals; D005724:Ganglia / Q000166:cytology; D006110:Grasshoppers / Q000502:physiology*; D007150:Immunohistochemistry; D009490:Neurosecretory Systems / Q000166:cytology; D009655:Octopamine / Q000276:immunology / Q000378:metabolism*; D013194:Staining and Labeling; D013909:Thorax / Q000276:immunology / Q000294:innervation*; D005680:gamma-Aminobutyric Acid / Q000276:immunology / Q000378:metabolism
D009655:Octopamine; D005680:gamma-Aminobutyric Acid