201 HCN Channels Blockade Attenuates Chemotherapy-Induced Pain

Abstract

Abstract INTRODUCTION Painful peripheral neuropathy is a common dose-limiting side effect caused by chemotherapy agents, such as oxaliplatin. Mechanisms underlying this devastating condition are largely unknown. METHODS We established a rat model of chemotherapy induced pain by administering oxaliplatin at 2 mg/Kg for 5 consecutive days. Mechanical hyperalgesia, a typical nociceptive pain behavior, developed after treatment with oxaliplatin. We investigated the expression of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels in the dorsal root ganglia (DRG) at both gene transcripts level (real-time PCR) and protein level (immunofluorescence). In addition, we examined the functional significance of HCN upregulation after oxaliplatin treatment by using a pan HCN channels blocker-ZD 7288. RESULTS >DRG HCN 1 and HCN 2 were higher in oxaliplatin- treated rats than saline-treated controls, both for gene transcripts and proteins. ZD7288, when administered intrathecally, was able to alleviate, albeit not abrogate, oxaliplatin induced-pain. Interestingly, pre-treatment with ZD7288 prior to oxaliplatin administration did not prevent the development of mechanical hyperalgesia. CONCLUSION Taken together, HCN1 and HCN2 channels are upregulated by oxaliplatin treatment, and that HCN blockade alleviates oxaliplatin-induced pain. Therefore, targeting HCN channels may provide a therapeutic avenue to treat chemotherapy induced-pain.