Functional neurokinin NK-1 receptor expression in rat peritoneal mast cells.
OBJECTIVE
Recently, Ogawa et al. [17] reported that the peritoneal mast cells (PMCs) of rats can release histamine by substance P (SP) in a receptor-dependent manner. In the present study, we confirmed and extended their findings.


METHODS
PMCs were isolated from six strains of rats. In some experiments, peritoneal cells in the non-MC fraction were used.


METHODS
PMCs were incubated with SP, neurokinin (NK) receptor agonists or antagonists, and histamine content in the supernatant was measured. In the binding assay, PMCs were incubated with [125I]BH-SP together with SP or NK receptor antagonists. NK-1 receptor mRNA was detected using a reverse transcription-polymerase chain reaction (RT-PCR) assay.


RESULTS
PMCs from Slc: Wistar and F344/NSlc were highly sensitive to SP, leading to histamine release, whereas those from Slc:SD and three other strains were not. PMCs from Slc:Wistar and F344/NSlc also released histamine in the presence of an NK-1 agonist. The histamine release induced by SP and the NK-1 agonist was inhibited by the NK-1 receptor antagonists, FK888 and CP-99,994. [125I]BH-SP binding experiments revealed that PMCs from Slc:Wistar rats possessed a single high affinity binding site for SP and that the binding was blocked by NK-1 receptor antagonists. Peritoneal cells in the non-MC fraction exhibited no appreciable binding. In the RT-PCR assay, expression of NK-1 receptor mRNA was evident in Slc:Wistar PMCs, but not in the non-MC fraction from Slc:Wistar or Slc: SD PMCs.


CONCLUSIONS
These data demonstrate the existence of functional NK-1 receptors on freshly isolated PMCs in at least some strains of rats.
Okada
T
T
Department of Immunology and Inflammation, Medicinal Biology Research Laboratories, Fujisawa Pharmaceutical Co., Ltd., Osaka, Japan.
Hirayama
Y
Y
Kishi
S
S
Miyayasu
K
K
Hiroi
J
J
Fujii
T
T
D000818:Animals; D006636:Histamine Release / Q000187:drug effects; D008297:Male; D008407:Mast Cells / Q000187:drug effects / Q000378:metabolism*; D064729:Neurokinin-1 Receptor Antagonists; D010529:Peritoneal Cavity / Q000166:cytology; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D011916:Rats, Inbred F344; D017208:Rats, Wistar; D018040:Receptors, Neurokinin-1 / Q000096:biosynthesis* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013373:Substance P / Q000378:metabolism; D013388:Succinimides / Q000378:metabolism
C043194:Bolton Hunter reagent-substance P conjugate; D064729:Neurokinin-1 Receptor Antagonists; D012333:RNA, Messenger; D018040:Receptors, Neurokinin-1; D013388:Succinimides; D013373:Substance P