3-iodothyroacetic acid, a metabolite of thyroid hormone, induces itch and reduces threshold to noxious and to painful heat stimuli in mice

摘要: Background and purpose Itch is associated with increased sensitization to nociceptive stimuli. We investigated whether 3-iodothyroacetic acid (TA1), by releasing histamine, induces itch increases noxious painful heat stimuli. Experimental Approach Itch was evaluated after s.c. administration of TA1 (0.4, 1.32 4 μg·kg−1). Mice threshold (NHT) stimuli were the increasing-temperature hot plate (from 45.5 49.5°C) or (51.5°C) test, respectively, 15 min i.p. injection Itch, NHT pain evaluation repeated in mice pretreated pyrilamine. Itch also measured HDC+/+ HDC−/− following saline (1.32, 4 11 μg·kg−1; i.p.). pERK1/2 levels determined Western blot dorsal root ganglia (DRG) isolated from CD1 they received (i.p.): saline, stimulus (46.5°C), (0.1, 0.4, 1.32, 4 μg·kg−1) 1.32 μg·kg−1 stimulus. Key Results TA1 0.4 induced reduced NHT; pyrilamine pretreatment prevented both these effects. 4 μg·kg−1 (i.p.) without inducing modifying NHT. In mice, failed induce reduce DRG, significantly 0.1, 1.32 μg·kg−1; i.p. Conclusions Implications Increased an enhanced sensitivity suggesting that might represent a potential cause thyroid diseases.