Different dorsal horn neurons responding to histamine and allergic itch stimuli.

Abstract

We examined whether different itch signals converge on the same dorsal horn neurons in mice. Intradermal injections of histamine and SLIGRL-NH2 (protease-activated receptor-2 agonist) induced scratching in naive mice and so did mosquito allergen in sensitized mice. These stimuli induced Fos expression in cells in the superficial dorsal horn. Fos-positive cells were mainly distributed within the isolectin B4-labeled region (inner aspect of lamina II) after histamine injection. In contrast, they were in the region dorsal to the isolectin B4-labeled region after injections of SLIGRL-NH2 and mosquito allergen. These results suggest that allergic itch signal is mediated by primary afferents expressing protease-activated receptor-2 and the neurons receiving signals of protease-associated itch and allergy-associated itch are different from those of histamine-induced itch.

• Authors: Tasuku Nakano, Tsugunobu Andoh, Jung-Bum Lee, Yasushi Kuraishi
• Journal: Neuroreport (Neuroreport) Vol. 19 Issue 7 Pg. 723-6 (May 07 2008) ISSN: 0959-4965 [Print] England
• PMID: 18418246 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Proto-Oncogene Proteins c-fos
• Receptor, PAR-2
• Histamine

Topics

• Afferent Pathways (cytology, metabolism)
• Animals
• Histamine (pharmacology)
• Hypersensitivity (metabolism)
• Immunohistochemistry
• Mice
• Mice, Inbred ICR
• Posterior Horn Cells (cytology, metabolism)
• Proto-Oncogene Proteins c-fos (metabolism)
• Pruritus (etiology, metabolism)
• Receptor, PAR-2 (metabolism)
• Skin (innervation)