Effects of chlorogenic acid on voltage-gated potassium channels of trigeminal ganglion neurons in an inflammatory environment

Chlorogenic acid (CGA) composed of coffee acid and quinic acid is an effective ingredient of many foods and medicines and widely exhibits biological effects. Recently, it is reported to have analgesic effect. However, little is known about the analgesic mechanism of CGA. In this study, whole-cell patch-clamp recordings were performed on two main subtypes (I-K,I-A and I-K,I-v channels) of voltage-gated potassium (K-v) channels in small-diameter(<30 mu m) trigemianl ganglion neurons to analyze the effects of CGA in an inflammatory environment created by Prostaglandin E-2 (PGE(2)). On one hand, the activation and inactivation V-1/2 values of I-K,I-A and I-K,I-v channels showed an elevation towards a depolarizing shift caused by PGE(2). On the other hand, the activation and inactivation V-1/2 values of the two channels had a reduction towards a hyperpolarizing shift caused by CGA under PGE(2) pretreatment. Our results demonstrated that CGA may exhibited an analgesic effect by promoting Kv channels activation and inactivation under inflammatory condition, which provided a novel molecular and ionic mechanism underlying anti-inflammatory pain of CGA. (C) 2016 Elsevier Inc. All rights reserved.