Figure 3: TRPA1 and the acetaminophen metabolite NAPQI are present in the spinal cord. | Nature Communications

Figure 3: TRPA1 and the acetaminophen metabolite NAPQI are present in the spinal cord.

From: TRPA1 mediates spinal antinociception induced by acetaminophen and the cannabinoid Δ9-tetrahydrocannabiorcol

Figure 3

Immunohistochemical DAB staining displays TRPA1 immunoreactivity in the superficial layers of the dorsal horn at cervical (a), thoracic (b) and lumbar (c) levels of the rat spinal cord. No TRPA1 immunoreactivity is observed in the absence of primary antibody (d) or after co-incubation with primary antibody and blocking peptide (e). (f) The distribution of TRPA1 overlaps with that of TRPV1, calcitonin gene-related peptide (CGRP) and substance P (SP). The stable NAPQI metabolite L-cysteinyl-S-acetaminophen is detected in the mouse spinal cord 30 min and 60 min after subcutaneous injection of 300 mg kg−1 of acetaminophen (APAP; g). Mass spectrum of L-cysteinyl-S-APAP obtained at positive mode [M+H]+=271.1 m/z; the fragmented ion m/z 140.2 was selected for quantification of L-cysteinyl-S-APAP (h). Chromatograms (m/z 271.1>140.2) of mouse spinal cord samples spiked with 370 nM of the reference compound L-cysteinyl-S-APAP (i) and 30 min after in vivo administration of APAP (j) or its vehicle saline (k). The L-cysteinyl-S-APAP content was below the detection limit in vehicle-treated animals (k). Data show mean±s.e.m. for 6 mice per group. **P<0.01; ***P<0.001 compared with vehicle-treated animals (Mann–Whitney test). Scale bars represent 500 μm in a–e and 100 μm in f.

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