Protein kinase C epsilon contributes to basal and sensitizing responses of TRPV1 to capsaicin in rat dorsal root ganglion neurons


Dr A. Sculptoreanu and Dr J. C. Glorioso, as above.
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Phosphorylation of the vanilloid receptor (TRPV1) by protein kinase C epsilon (PKCɛ) plays an important role in the development of chronic pain. Here, we employ a highly defective herpes simplex virus vector (vHDNP) that expresses dominant negative PKCɛ (DNPKCɛ) as a strategy to demonstrate that PKCɛ is essential for: (i) maintenance of basal phosphorylation and normal TRPV1 responses to capsaicin (CAPS), a TRPV1 agonist and (ii) enhancement of TRPV1 responses by phorbol esters. Phorbol esters induced translocation of endogenous PKCɛ to the plasma membrane and thereby enhanced CAPS currents. These results were extended to an in-vivo pain model in which vHDNP delivery to dorsal root ganglion neurons caused analgesia in CAPS-treated, acutely inflamed rat hind paws. These findings support the conclusion that in addition to receptor sensitization, PKCɛ is essential for normal TRPV1 responses in vitro and in vivo.