The Lack of TRPA1 Ion Channel Does Not Affect the Chronic Stress-Induced Activation of the Locus Ceruleus

Abstract

We have previously proven the involvement of transient receptor potential ankyrin 1 (TRPA1) in stress adaptation. A lack of TRPA1 affects both urocortin 1 (member of the corticotropin-releasing hormone (CRH) family) content of the Edinger–Westphal nucleus. The noradrenergic locus ceruleus (LC) is also an important player in mood control. We aimed at investigating whether the TRPA1 is expressed in the LC, and to test if the response to chronic variable mild stress (CVMS) is affected by a lack of TRPA1. The TRPA1 expression was examined via RNAscope in situ hybridization. We investigated TRPA1 knockout and wildtype mice using the CVMS model of depression. Tyrosine hydroxylase (TH) and FOSB double immunofluorescence were used to test the functional neuromorphological changes in the LC. No TRPA1 expression was detected in the LC. The TH content was not affected by CVMS exposure. The CVMS-induced FOSB immunosignal did not co-localize with the TH neurons. TRPA1 is not expressed in the LC. A lack of functional TRPA1 receptor neither directly nor indirectly affects the TH content of LC neurons under CVMS.