Effects of an intrathecal TRPV1 antagonist, SB366791, on morphine-induced itch, body temperature, and antinociception in mice

• Published in: Journal of pain research Vol. 12; pp. 2629 - 2636
• Main Authors: Sakakibara, Satoshi, Imamachi, Noritaka, Sakakihara, Manabu, Katsube, Yukiko, Hattori, Mai, Saito, Yoji
• Format: Journal Article
• Language: English
• Published: New Zealand Dove Medical Press Limited 01.01.2019; Taylor & Francis Ltd; Dove; Dove Medical Press
• Subjects: Analysis; Anesthesiology; Body temperature; Bone cancer; Drug dosages; Experiments; Fever; Histamine; Hyperthermia; Itching; Medical research; Morphine; Narcotics; Neurosciences; nociception; opioid; Original Research; Pain; Pruritus; TRPV1; University faculty; Variance analysis; Japan; pruritus; nociception; hyperthermia; TRPV1; opioid
• ISSN: 1178-7090; 1178-7090
• DOI: 10.2147/jpr.s217439

Transient receptor potential vanilloid 1 (TRPV1) not only is activated by multiple stimuli but also is involved with histamine-induced itch. The effects of TRPV1 on morphine-induced itch are unknown. We examined the effects of intrathecal administration of TRPV1 antagonist on morphine-induced itch, body temperature, and antinociception for mice. Each C57/BL6j mouse was intrathecally administered with one of the following solutions: morphine, SB366791 (as the TRPV1 antagonist), morphine + SB366791, saline, or vehicle. For each mouse, each instance of observed scratching behavior was counted, the body temperature was measured, and the nociceptive threshold was determined using the tail-immersion test. SB366791 dose-dependently reduced the scratching behavior induced by the administration of morphine. SB366791 and the morphine + SB366791 groups did not manifest an increase in body temperature. Antinociceptive effects were observed to occur dose-dependently for morphine but not for SB366791. Compared with morphine alone, the administration of morphine + SB366791 did not reduce significant antinociceptive effects. We propose that an intrathecal TRPV1 antagonist, SB366791, reduced morphine-induced itch without causing hyperthermia and did not suppress morphine-induced antinociception for mice.