Figure 5.
Lipid peroxidation products and 15d-PGJ2 are TRPA1 agonists. A, [Ca2+]i increases evoked by 4-ONE (3 μm), 4-HNE (30 μm), and 15d-PGJ2 (20 μm) in DRG neurons. Sequential applications of AITC and capsaicin (Caps) show that 4-ONE, 4-HNE, and 15d-PGJ2 activate the same subset of TRPV1-expressing, capsaicin-sensitive neurons as AITC. B, Left, 4-HNE-evoked current in a TRPA1 CHO cell initially in calcium-free solution. Admission of calcium led to rapid inactivation. Right, Current–voltage relationship of 4-HNE-evoked current. C, Left, 4-HNE-evoked current in a DRG neuron (external solution containing 15 μm Ca2+, −60 mV). Right, Current–voltage relationship of the 4-HNE-evoked current in the same neuron. D, Time course (left) and voltage-dependent kinetics (right) for 15d-PGJ2-evoked TRPA1 current in a CHO cell. Right, Current–voltage relationship of 15d-PGJ2-evoked current.