Investigating the potential role of TRPA 1 in locomotion and cardiovascular control during hypertension

Radiotelemetry was used to investigate the in vivo cardiovascular and activity phenotype of both TRPA 1 (transient receptor potential ankyrin 1) wild‐type ( WT ) and TRPA1 knockout ( KO ) mice. After baseline recording, experimental hypertension was induced using angiotensin II infusion (1.1 mg −1  kg −1 a day, for 14 days). TRPA 1 WT and KO mice showed similar morphological and functional cardiovascular parameters, including similar basal blood pressure ( BP ), heart rate, size, and function. Similar hypertension was also displayed in response to angiotensin II (156 ± 7 and 165 ± 11 mmHg, systolic BP  ±  SEM , n  = 5–6). TRPA 1 KO mice showed increased hypertensive hypertrophy (heart weight:tibia length: 7.3 ± 1.6 mg mm −1 vs. 8.8 ± 1.7 mg mm −1 ) and presented with blunted interleukin 6 ( IL ‐6) production compared with hypertensive WT mice (151 ± 24 vs. 89 ± 16 pg mL −1 ). TRPA 1 expression in dorsal root ganglion ( DRG ) neurones was upregulated during hypertension (163% of baseline expression). Investigations utilizing the TRPA 1 agonist cinnamaldehyde ( CA ) on mesenteric arterioles isolated from näive mice suggested a lack of TRPA 1‐dependent vasoreactivity in this vascular bed; a site with notable ability to alter total peripheral resistance. However, mesenteric arterioles isolated from TRPA 1 KO hypertensive mice displayed significantly reduced ability to relax in response to nitric oxide ( NO ) ( P  < 0.05). Unexpectedly, naïve TRPA 1 KO mice also displayed physical hyperactivity traits at baseline, which was exacerbated during hypertension. In conclusion, our study provides a novel cardiovascular characterization of TRPA 1 KO mice in a model of hypertension. Results suggest that TRPA 1 has a limited role in global cardiovascular control, but we demonstrate an unexpected capacity for TRPA 1 to regulate physical activity.