title: The effects of four neuropeptides on the degranulation of mucosal mast cells from sheep.
abstract: Isolated mucosal mast cells (MMC) were used to examine the ability of four neuropeptides, substance P, vasoactive intestinal peptide, beta-endorphin and somatostatin, to release mediators in the presence or absence of parasite antigen. None of the neuropeptides induced the release of sheep mast cell protease (SMCP) or histamine from MMC of helminth-immune sheep in the absence of parasite antigen. Incubation of immune MMC with 100 and 1.0 microgram/mL parasite antigen induced 32.1 and 15.5% specific SMCP release, respectively. While the neuropeptides did not augment SMCP release at 100 micrograms/mL parasite antigen, significant enhancement (40-98%) of SMCP release at 1 microgram/mL antigen was obtained by each neuropeptide at concentrations from 10(-8) to 10(-12) mol/L. The results provide additional support for modulation of MMC degranulation by neural activity in sheep and, to our knowledge, this is the first demonstration that the threshold antigen concentration for allergic responses may also be lowered by neuropeptides to render the reaction more sensitive to antigen.
authors.affiliation: CSIRO Division of Animal Production, McMaster Laboratory, Blacktown, NSW, Australia.
authors.forename: M J
authors.initials: MJ
authors.lastname: Stewart
authors.forename: D L
authors.initials: DL
authors.lastname: Emery
authors.forename: S J
authors.initials: SJ
authors.lastname: McClure
authors.forename: T
authors.initials: T
authors.lastname: Bendixsen
mesh_terms: D000818:Animals; D000947:Antigens, Helminth / Q000494:pharmacology; D015550:Cell Degranulation / Q000276:immunology*; D006636:Histamine Release / Q000187:drug effects; D007413:Intestinal Mucosa / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D008297:Male; D008407:Mast Cells / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism*; D009479:Neuropeptides / Q000494:pharmacology*; D012756:Sheep; D013004:Somatostatin / Q000494:pharmacology; D013373:Substance P / Q000494:pharmacology; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology; D001615:beta-Endorphin / Q000494:pharmacology
chemical_list: D000947:Antigens, Helminth; D009479:Neuropeptides; D013373:Substance P; D014660:Vasoactive Intestinal Peptide; D013004:Somatostatin; D001615:beta-Endorphin