Introduction: Capsaicin-sensitive sensory neurons express Transient Receptor Potential Ankyrin 1 (TRPA1) and Vanilloid 1 (TRPV1) receptors. TRPA1 can be activated by several chemical stimuli, such as allylisothiocyanate (AITC), the pungent agent of mustard oil, resulting in the release of vasoactive inflammatory neuropeptides like calcitonin-gene-related-peptide (CGRP). The gaseous mediator hydrogen-sulphide (H2S) has been recently suggested to act on capsaicin-sensitive sensory neurons. Therefore, the aim of our present study was to investigate the involvement of TRPA1 receptors in H2S-evoked CGRP-release from sensory nerves in vitro and microcirculatory changes in vivo. Methods: In vitro experiments were performed on isolated tracheae of male and female Wistar rats (200-250 g). Tracheae were removed in deep anaesthesia (sodium thiopentone, 100 mg/kg, i.p.). Sensory nerve terminals of the isolated rat tracheae were stimulated by increasing concentrations of AITC or the H2S-donor NaHS and CGRP-release was measured by radioimmunoassay. The effects of the TRPA1 antagonist HC-030031 and the TRPV1 antagonist BCTC were tested on this response. In vivo experiments were carried out on Balb/c mice for testing pharmacological inhibition by HC-030031, while TRPA1 (TRPA1-/-) and TRPV1 gene-deficient (TRPV1-/-) mice were compared to their wild types (WTs, 25-30 g). Measurements were performed under ketamine (100 mg/kg, s.c.) and xylazine (5 mg/kg, s.c.) anaesthesia. Vasodilatation of the murine ear was evoked by AITC (15 μl, 2%) or NaHS (15 μl, 5%) and skin blood flow was measured by laser Doppler imaging for 30 minutes in case of AITC-, and for 50 minutes in case of NaHS-application. Results: Both AITC and NaHS elicited concentration-dependent release of CGRP in the rat tracheae. CGRP-release induced by AITC amounted to 1.46±0.31 fmol/mg, which was only 0.14±0.06 fmol/mg in the presence of 100 μmol/l of HC-030031. NaHS-evoked CGRP-release reached 0.47±0.09 fmol/mg, which was only 0.0008 fmol/mg when HC-030031 (100 μmol/l) was applied. In the presence of BCTC, NaHS-induced CGRP-release amounted to 0.52±0.05 fmol/mg. AITC evoked an increased skin blood flow with a maximum value of 27.87%±2.31% above baseline at 6 minutes. 30 or 100 mg/kg of HC-030031 inhibited AITC-evoked vasodilation by 54.5% and 53.6%, respectively. NaHS increased cutaneous microcirculation with a peak value of 67.42%±4.87% above baseline at 48 min. 30 and 100 mg/kg of HC-030031 inhibited NaHS-induced vasodilatation by 24.6% and 51.4%, respectively. In wild type mice, maximum value of blood flow amounted to 17.36%±4.1%. In the TRPA1-/- animals it reached only -1.69%±4.17%, while in the TRPV1 knockouts it peaked at 17.77%±5.28%. In WTs, NaHS caused a 44.18%±3.19% increase of microcirculation. In the TRPA1-/- mice it reached only 23.75%±4.09%, while in the TRPV1-/- animals it peaked at 35.73%±3.29%. Conclusion: Similarly to the effect of AITC, NaHS also evoked a concentration-dependent CGRP-release, which was inhibited by HC-030031, but not by BCTC. Likewise AITC, NaHS also increased cutaneous microcirculation in the mouse ears, and this vasodilatory response to NaHS could be ameliorated by HC-030031. Blood flow of TRPA1-/-, but not the TRPV1-/- mice showed significantly smaller increase in response to NaHS compared to the wild types. Activation of TRPA1 receptors plays an important role in H2S-induced CGRP-release and cutaneous vasodilatation in the murine ear, while TRPV1 receptors are not involved in these processes. Our results highlight that TRPA1 receptor activation should be minded as a potential mechanism of vasoactive effects of H2S.