HISTAMINE-INDUCED INTERNALIZATION OF SUBSTANCE-P RECEPTORS IN MYOEPITHELIAL CELLS OF THE GUINEA-PIG NASAL GLANDS

Numerous substance P (SP) immunoreactive nerve fibers were located aro und submucosal glands in the guinea pig nasal mucosa. Since these SP p ositive nerve fibers were also positive for vasoactive intestinal poly peptide, and to a lessor extent for neuropeptide Y, they were presumed to be parasympathetic fibers. SP receptor positive structures were ob served exclusively on the membrane of myoepithelial cells in normal na sal mucose, suggesting that myoepithelial cells are targets of SP posi tive fibers. SP receptor-like immunoreactivity was observed associated with intracellular organella of myoepithelial cells 5 min after intra nasal histamine challenge, which may indicate the molecular basis for histamine-induced nasal discharge. (C) 1998 Elsevier Science Inc.