1. Complementary roles of murine Na V 1.7, Na V 1.8 and Na V 1.9 in acute itch signalling.
- Author
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Kühn H, Kappes L, Wolf K, Gebhardt L, Neurath MF, Reeh P, Fischer MJM, and Kremer AE
- Subjects
- Animals, Mice, Mice, Knockout, NAV1.7 Voltage-Gated Sodium Channel chemistry, NAV1.8 Voltage-Gated Sodium Channel chemistry, NAV1.9 Voltage-Gated Sodium Channel chemistry, Pruritus chemically induced, Pruritus pathology, Signal Transduction, Histamine toxicity, NAV1.7 Voltage-Gated Sodium Channel physiology, NAV1.8 Voltage-Gated Sodium Channel physiology, NAV1.9 Voltage-Gated Sodium Channel physiology, Pruritus prevention & control
- Abstract
Acute pruritus occurs in various disorders. Despite severe repercussions on quality of life treatment options remain limited. Voltage-gated sodium channels (Na
V ) are indispensable for transformation and propagation of sensory signals implicating them as drug targets. Here, NaV 1.7, 1.8 and 1.9 were compared for their contribution to itch by analysing NaV -specific knockout mice. Acute pruritus was induced by a comprehensive panel of pruritogens (C48/80, endothelin, 5-HT, chloroquine, histamine, lysophosphatidic acid, trypsin, SLIGRL, β-alanine, BAM8-22), and scratching was assessed using a magnet-based recording technology. We report an unexpected stimulus-dependent diversity in NaV channel-mediated itch signalling. NaV 1.7-/- showed substantial scratch reduction mainly towards strong pruritogens. NaV 1.8-/- impaired histamine and 5-HT-induced scratching while NaV 1.9 was involved in itch signalling towards 5-HT, C48/80 and SLIGRL. Furthermore, similar microfluorimetric calcium responses of sensory neurons and expression of itch-related TRP channels suggest no change in sensory transduction but in action potential transformation and conduction. The cumulative sum of scratching over all pruritogens confirmed a leading role of NaV 1.7 and indicated an overall contribution of NaV 1.9. Beside the proposed general role of NaV 1.7 and 1.9 in itch signalling, scrutiny of time courses suggested NaV 1.8 to sustain prolonged itching. Therefore, NaV 1.7 and 1.9 may represent targets in pruritus therapy.- Published
- 2020
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