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FMRF-amide immunoreactivity in a moth larva (Heliothis zea): The cerebral nervous system
A C Jenkins1, M R Brown, J W Crim
1Department of Zoology, University of Georgia, Athens, GA 30602 USA Telephone: (404)542-3310.
Abstract:
The cerebral nervous system of the larval corn earworm, Heliothis zea, was examined using light microscopy and immunocytochemistry. Immunoreactivity for the molluscan cardioactive peptide FMRF-amide (FMRFa) is widely distributed. Staining is localized in perikarya and axons of the brain, subesophageal ganglion and first thoracic ganglion. Immunoreactive axons are also found in the frontal ganglion and the corpora cardiaca. Crossreactivity studies for FMRFa and bovine pancreatic polypeptide (BPP) demonstrate that (a) the immunoreactive material is more FMRFa-like than BPP-like and (b) the antigenic material is heterogeneous. For animals on different feeding regimens, immunocytochemical surveys and radioimmunoassay suggest the observed variation in immunoreactivity among individuals is unrelated to feeding state.
Insights
The corn earworm
Area of Science:
- Neuroscience
- Insect Physiology
- Biochemistry
Background:
- The corn earworm (Heliothis zea) is a significant agricultural pest.
- Understanding its nervous system is crucial for developing targeted control strategies.
- FMRF-amide (FMRFa) is a neuropeptide found in various invertebrates, regulating physiological functions.
Purpose of the Study:
- To investigate the distribution and characteristics of FMRF-amide (FMRFa) immunoreactivity in the larval corn earworm's central nervous system.
- To determine if feeding regimens influence FMRFa expression.
Main Methods:
- Light microscopy and immunocytochemistry were employed to visualize FMRFa.
- Cross-reactivity studies with bovine pancreatic polypeptide (BPP) were performed.
- Radioimmunoassay was used to assess FMRFa levels.
Main Results:
- FMRFa immunoreactivity was widespread in the brain, subesophageal ganglion, and thoracic ganglion.
- Immunoreactive axons were observed in the frontal ganglion and corpora cardiaca.
- The immunoreactive material was primarily FMRFa-like and heterogeneous, with variations unrelated to feeding state.
Conclusions:
- FMRF-amide (FMRFa) is extensively distributed in the larval corn earworm's nervous system.
- The observed heterogeneity in FMRFa suggests complex processing or multiple forms of the peptide.
- Feeding status does not appear to influence FMRFa immunoreactivity in this species.
