Human pain ratings to electrical sinusoids increase with cooling through a cold-induced increase in C-fibre excitability

• Verfasst von: Pakalniškis, Julius [VerfasserIn]
• Verfasst von: Soares, Sabrina [VerfasserIn]
• Verfasst von: Rajan, Suhasini [VerfasserIn]
• Verfasst von: Vyshnevska, Alina [VerfasserIn]
• Verfasst von: Schmelz, Martin [VerfasserIn]
• Verfasst von: Solinski, Hans Jürgen [VerfasserIn]
• Verfasst von: Rukwied, Roman [VerfasserIn]
• Verfasst von: Carr, Richard [VerfasserIn]
• Titel: Human pain ratings to electrical sinusoids increase with cooling through a cold-induced increase in C-fibre excitability
• Verf.angabe: Julius Pakalniskis, Sabrina Soares, Suhasini Rajan, Alina Vyshnevska, Martin Schmelz, Hans Jürgen Solinski, Roman Rukwied, Richard Carr
• E-Jahr: 2023
• Jahr: July 2023
• Umfang: 13 S.
• Illustrationen: Illustrationen
• Fussnoten: Gesehen am 02.07.2024
• Titel Quelle: Enthalten in: Pain
• Ort Quelle: New York, NY [u.a.] : Lippincott Williams and Wilkins, 1975
• Jahr Quelle: 2023
• Band/Heft Quelle: 164(2023), 7, Artikel-ID 1524, Seite 1524-1536
• ISSN Quelle: 1872-6623
• DOI: doi:10.1097/j.pain.0000000000002849
• Datenträger: Online-Ressource
• Sprache: eng
• K10plus-PPN: 1893100766

Abstract

Low-frequency sinusoidal current applied to human skin evokes local axon reflex flare and burning pain, indicative of C-fibre activation. Because topical cooling works well as a local analgesic, we examined the effect of cooling on human pain ratings to sinusoidal and rectangular profiles of constant current stimulation. Unexpectedly, pain ratings increased upon cooling the skin from 32 to 18°C. To explore this paradoxical observation, the effects of cooling on C-fibre responses to stimulation with sinusoidal and rectangular current profiles were determined in ex vivo segments of mouse sural and pig saphenous nerve. As expected by thermodynamics, the absolute value of electrical charge required to activate C-fibre axons increased with cooling from 32°C to 20°C, irrespective of the stimulus profile used. However, for sinusoidal stimulus profiles, cooling enabled a more effective integration of low-intensity currents over tens of milliseconds resulting in a delayed initiation of action potentials. Our findings indicate that the paradoxical cooling-induced enhancement of electrically evoked pain in people can be explained by an enhancement of C-fibre responsiveness to slow depolarization at lower temperatures. This property may contribute to symptoms of enhanced cold sensitivity, especially cold allodynia, associated with many forms of neuropathic pain.