Jackson Estuarine Laboratory
Presence and distribution of immunoreactive and bioactive FMRFamide-like peptides in the nervous system of the horseshoe crab, limulus polyphemus
Abstract
FMRFamide immunoreactivity was detected in all regions of the Limulus nervous system, including the brain (6.5±0.6 pg FMRFamide/mg), cardiac ganglion (2.06±0.67 pg FMRFamide/mg), and ventral nerve cord (5.8±0.7 pg FMRFamide/mg). The distribution of immunoreactive FMRFamide (irFMRFamide) was mapped by immunofluorescence and the distribution corresponded to regional RIA data. A good proportion of the CNS and cardiac ganglion neuropile contained irFMRFamide, and fluorescent cell bodies were observed in several areas. High performance liquid chromatography (HPLC) was employed to separate and characterize the FMRFamide-like peptides from extracts of Limulus brains. HPLC fractions were analyzed using coincidental radioimmunoassay and bioassay (the radula protractor muscle of Busycon contrarium). There appear to be at least three FMRFamide-like peptides in the Limulus brain, including one similar to clam FMRFamide. FMRFamide acts on Limulus heart in a biphasic manner at relatively high concentrations (10−5 M), but has no effect on the activity of the isolated ventral nerve cord. These data suggest that in Limulus FMRFamide-like peptides are acting as neurotransmitters, or neuromodulators.
Department
Jackson Estuarine Laboratory, Biological Sciences
Publication Date
5-1-1984
Journal Title
Peptides
Publisher
Elsevier
Digital Object Identifier (DOI)
https://doi.org/10.1016/0196-9781(84)90089-5
Document Type
Article
Rights
© 1984 Published by Elsevier Inc.
Recommended Citation
Watson, W. H., J. R. Groome, T. L. O'Donohue, B. M. Chronwall and J. Bishop. l984. Presence and distribution of immunoreactive and bioactive FMRFamide-like peptides in the nervous system of the horseshoe crab, Limulus polyphemus. Peptides 5: 585-592. https://doi.org/10.1016/0196-9781(84)90089-5