SOMATOSENSORY SYSTEMS, PAINMolecular mechanisms underlying calcium current modulation by nociceptinYeon, Kyu-Young; Sim, Mi-Young; Choi, Se-Young; Lee, Sung Joong; Park, Kyungpyo; Kim, Joong Soo; Lee, Jong-Heun; Lee, Kyung-Mi1 CA; Oh, Seog BaeCAAuthor Information Department of Physiology, College of Dentistry and Dental Research Institute, Seoul National University, Seoul 110-749; 1Department of Biochemistry, Korea University College of Medicine, Sungbuk-Gu, Anam-Dong, Seoul 136-705, Korea CACorresponding Authors: email@example.com;firstname.lastname@example.org Received 3 June 2004; accepted 5 July 2004 NeuroReport: October 5th, 2004 - Volume 15 - Issue 14 - p 2205-2209 Buy SDC Abstract Nociceptin is a non-opioid peptide that modulates pain response. One of mechanism underlying its analgesic action is the inhibition of voltage-dependent calcium current (ICa), similar to that of opioids. We investigated the molecular mechanism by which nociceptin inhibits ICa using sensory neurons and a heterologous expression system. ICa inhibition by nociceptin was voltage-dependent, exhibited the slowing of activation kinetics and prepulse facilitation, and was blocked by N-ethylmaleimide, indicating the involvement of Gi/Go protein. ICa inhibition by nociceptin was primarily mediated through binding to its own receptor, ORL-1, but not through affecting other μ-opioid receptors. Thus, our results strongly demonstrate that heterologous cross-talk between ORL1 and μOR is not involved in the ICa inhibition by nociceptin. © 2004 Lippincott Williams & Wilkins, Inc.