Fig. 3
Trpa1 mediates 2MT/TMT/snake skin-evoked innate fear/defensive responses. a, b Wild-type, heterozygous, and homozygous Trpa1 (a) and Trpv1 (b) knockout mice were examined for innate freezing behaviors evoked by 2MT or TMT. Data are presented as mean ± SEM (Student’s t-test, ***P < 0.001; **P < 0.01; ns not significant). c Plasma concentration of stress hormone corticosterone was measured in Trpa1+/− and Trpa1−/− mice following exposure to H2O or 2MT for 20 min. Data are presented as mean ± SEM (n = 6, two-way ANOVA test, **P < 0.01). d Representative avoidance tracks of Trpa1+/− and Trpa1−/− mice in response to low concentration (1.05 × 10−6 mole) of 2MT exposure in the test cage. The black box indicates the position of 2MT-containing filter paper. e Quantitative analysis of freezing, risk assessment, flight, and investigation behaviors of Trpa1+/− and Trpa1−/− mice in testing cages in response to low-dose 2MT exposure. Data are presented as mean ± SEM (n = 7, Student’s t-test, ***P < 0.001; **P < 0.01, *P < 0.05). f An image depicting the snake skin-evoked innate fear assay in the home cage. g Quantitative analysis of snake skin-evoked freezing, risk assessment, avoidance, flight, and investigation behaviors of Trpa1+/− and Trpa1−/− mice. Data are presented as mean ± SEM (n = 6, Student’s t-test, ***P < 0.001; **P < 0.01)
