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Identification, physiological actions, and distribution of VYRKPPFNGSIFamide (Val 1 ‐SIFamide) in the stomatogastric nervous system of the American lobster Homarus americanus
Author(s) -
Christie Andrew E.,
Stemmler Elizabeth A.,
Peguero Braulio,
Messinger Daniel I.,
Provencher Heather L.,
Scheerlinck Pieter,
Hsu YunWei A.,
Guiney Maureen E.,
de la Iglesia Horacio O.,
Dickinson Patsy S.
Publication year - 2006
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.20932
Subject(s) - stomatogastric ganglion , biology , homarus , neuropil , immunolabeling , anatomy , neuroscience , central nervous system , medicine , zoology , immunohistochemistry , crustacean , central pattern generator , rhythm , immunology
In this study, the peptide VYRKPPFNGSIFamide (Val 1 ‐SIFamide) was identified in the stomatogastric nervous system (STNS) of the American lobster, Homarus americanus , using matrix‐assisted laser desorption/ionization‐Fourier transform mass spectrometry (MALDI‐FTMS). When bath‐applied to the stomatogastric ganglion (STG), synthetic Val 1 ‐SIFamide activated the pyloric motor pattern, increasing both burst amplitude and duration in the pyloric dilator (PD) neurons. To determine the distribution of this novel SIFamide isoform within the lobster STNS and neuroendocrine organs, a rabbit polyclonal antibody was generated against synthetic Val 1 ‐SIFamide. Whole‐mount immunolabeling with this antibody showed that this peptide is widely distributed within the STNS, including extensive neuropil staining in the STG and commissural ganglia (CoGs) as well as immunopositive somata in the CoGs and the oesophageal ganglion. Labeling was also occasionally seen in the pericardial organ (PO), but not in the sinus gland. When present in the PO, labeling was restricted to fibers‐of‐passage and was never seen in release terminals. Adsorption of the antibody by either Val 1 ‐SIFamide or Gly 1 ‐SIFamide abolished all Val 1 ‐SIFamide staining within the STNS, including the STG neuropil, whereas adsorption by other lobster neuropeptides had no effect on immunolabeling. These data strongly suggest that the staining we report is a true reflection of the distribution of this peptide in the STNS. Collectively, our mass spectrometric, physiological, and anatomical data are consistent with Val 1 ‐SIFamide serving as a locally released neuromodulator in the lobster STG. Thus, our study provides the first direct demonstration of function for an SIFamide isoform in any species. J. Comp. Neurol. 496:406–421, 2006. © 2006 Wiley‐Liss, Inc.