Activity-dependent targeting of TRPV1 with a pore-permeating capsaicin analog

作者：Li Hui; Wang Shu; Chuang Alexander Y; Cohen Bruce E; Chuang Huai hu^*

来源：Proceedings of the National Academy of Sciences of the United States of America, 2011, 108(20): 8497-8502.

DOI：10.1073/pnas.1018550108

• activity-dependent capsaicinoids
• hyperalgesia
• ion permeation
• selective analgesia

The capsaicin receptor TRPV1 is the principal transduction channel for nociception. Excessive TRPV1 activation causes pathological pain. Ideal pain mangement requires selective inhibition of hyperactive pain-sensing neurons, but sparing normal nociception. We sought to determine whether it is possible to use activity-dependent TRPV1 agonists to identify nerves with excessive TRPV1 activity, as well as exploit the TRPV1 pore to deliver charged anesthetics for neuronal silencing. We synthesized a series of permanently charged capsaicinoids and found that one, cap-ET, efficaciously evoked TRPV1-dependent entry of Ca(2+) or the large cationic dye YO-PRO-1 comparably to capsaicin, but far smaller electrical currents. Cap-ET-induced YO-PRO-1 transport required permeation of both the agonist and the dye through the TRPV1 pore and could be enhanced by kinase activation or oxidative covalent modification. Moreover, cap-ET reduced capsaicin-induced currents by a voltage-dependent block of the pore. A low dose of cap-ET elicited entry of permanently charged Na(+) channel blockers to effectively suppress Na(+) currents in sensory neurons presensitized with oxidative chemicals. These results implicate therapeutic potential of these unique TRPV1 agonists exhibiting activity-dependent ion transport but of minimal pain-producing risks.

• 出版日期2011-5-17