Helospectin-like peptides in the gastrointestinal tract: immunocytochemical localization and immunochemical characterization.
Helospectins I and II are two non-amidated, vasoactive intestinal peptide (VIP)-like peptides, isolated from the salivary gland venom of the lizard Heloderma horridum. Helospectin I has 38 amino acid residues and differs from helospectin II in that it has an additional serine residue at the C-terminus. The study was based on an antiserum that recognizes both helospectins I and II (but recognizes VIP only poorly). Immunocytochemistry of the digestive tract revealed helospectin-immunoreactive nerve fibers in the muscle layers, submucosa and mucosa of mouse, rat, hamster, guinea-pig and man. Myenteric and submucous ganglia in all species contained helospectin-immunoreactive nerve fibers and cell bodies. The distribution of helospectin-like immunoreactivity in the gut resembled that of VIP. Double immunostaining for helospectin and VIP revealed their co-existence in the same population of nerve fibers and cell bodies throughout the gut of all species tested. In addition, helospectin (but not VIP) immunoreactivity was observed in a population of endocrine cells in the intestines. The existence of helospectin-like material in the gut was confirmed by immunochemistry. The helospectin-like immunoreactivity in the extracts diluted in parallel to the helospectin standard curve. Analysis by high performance liquid chromatography of extracts of rat intestine revealed one predominant helospectin-immunoreactive peak that eluted close to authentic helospectins I and II. The helospectin-immunoreactive material in the gut may constitute a novel neuropeptide that co-exists with VIP. The distribution of the VIP-helospectin-immunoreactive neurons and fibers indicates their possible involvement in the regulation of gut motor and secretory activities.
Absood
A
A
Department of Pharmacology, University of Lund, Sweden.
Ekblad
E
E
Ekelund
M
M
Håkanson
R
R
Sundler
F
F
D000818:Animals; D002851:Chromatography, High Pressure Liquid; D006224:Cricetinae; D004064:Digestive System / Q000378:metabolism*; D005753:Gastric Mucosa / Q000378:metabolism; D006168:Guinea Pigs; D006801:Humans; D007150:Immunohistochemistry; D036341:Intercellular Signaling Peptides and Proteins; D008116:Lizards; D051379:Mice; D009130:Muscle, Smooth / Q000378:metabolism; D010455:Peptides / Q000378:metabolism*; D011863:Radioimmunoassay; D051381:Rats; D014660:Vasoactive Intestinal Peptide / Q000378:metabolism
D036341:Intercellular Signaling Peptides and Proteins; D010455:Peptides; D014660:Vasoactive Intestinal Peptide; C043046:helospectin I; C043047:helospectin II