Figure 1: Cold-induced vascular response is dependent on TRPA1.
From: TRPA1 is essential for the vascular response to environmental cold exposure
Blood flow was measured using FLPI in anaesthetized mice following immersion of the ipsilateral hindpaw in cold (10 °C) water and contralateral paw remained untreated. (a) Representative blood flow trace of a cold-induced response in WT and TRPA1 KO mice. (b) Representative FLPI pictures alongside grey/black ‘photo’ showing blood flow at baseline, 2 and 30 min in cold-treated hindpaw. (c) % Change in hindpaw blood flow from baseline to 0–2 min following cold treatment (maximum vasoconstriction) and (d) Restoration of cutaneous blood flow, as assessed by AUC for 30 min following cold treatment in WT (n=12) and TRPA1 KO (n=9) or WT mice pretreated with TRPA1 antagonist HC030031 (100 mg kg−1, i.p., 30 min, n=10) or control (10% DMSO in saline, i.p., 30 min, n=8) before cold treatment. (e) % Maximum change in hindpaw blood flow from baseline to 0–2 min following cold treatment (maximum vasoconstriction) in WT (n=10) and TRPM8 KO (n=14) mice or WT mice pretreated with TRPM8 antagonist AMTB (10 mg kg−1, i.p., 30 min, n=8) or control (10% DMSO in saline, i.p., 30 min, n=10) before cold exposure. (f) Representative trace of a cold-induced response in WT and TRPM8 KO mice. (g) Restoration of cutaneous blood flow, assessed by AUC for 30 min following cold treatment in WT (n=10) and TRPM8 KO (n=14) mice or WT mice pretreated with TRPM8 antagonist AMTB (10 mg kg−1, i.p., 30 min, n=8) or control (10% DMSO in saline, i.p., 30 min, n=10) before cold treatment. (h) % Change in hindpaw blood flow from baseline to 0–2 min following cold treatment (maximum vasoconstriction) and (i) Restoration of cutaneous blood flow, assessed by AUC for 30 min following cold treatment in TRPA1 WT (n=5) and KO (n=5) pretreated with control (10% DMSO in saline, i.p., 30 min) or TRPA1 WT (n=4) and KO (n=4) pretreated with AMTB (10 mg kg−1, i.p., 30 min). All error bars indicate s.e.m. *P<0.05, **P<0.01, ***P<0.001 versus respective untreated, #P<0.05, ##P<0.01, ###P<0.001 versus cold-treated, $P<0.05 versus cold-treated TRPA1 WT (analysis of variance, Bonferroni post hoc test).
