Tribute to Ronald Melzack | Open Access
Ruth C Riley, Jodie A Trafton, Allan I Basbaum, "Presynaptic control of nociceptor signalling: Differential influence of Mu Opioid and GABAergic Systems", Pain Research and Management, vol. 5, Article ID 780802, 12 pages, 2000. https://doi.org/10.1155/2000/780802
Presynaptic control of nociceptor signalling: Differential influence of Mu Opioid and GABAergic Systems
The relative contribution of pre- and postsynaptic controls to the flow of nociceptive information at the level of the spinal cord has been one of Ron Melzack's longstanding interests and a key issue in the formulation of the gate control theory. The authors review their own studies, in which they monitored internalization of the neurokinin-1 receptor to examine specifically the action of two classically inhibitory systems - mu opioid and gamma-amino butyric acid (GABA) - on noxious stimulus-evoked tachykinin signalling in the rat spinal cord. Evidence that opioids and GABAergic controls operate differently on the central consequences of any noxious stimulus-induced substance P release is provided. Whereas at least 80% of the tachykinin signalling remained intact after even the highest concentration of spinal morphine or D-Ala2, NMe-phe4, Glyol5-enkephalin administration, spinal administration of the GABAB receptor agonist baclofen had a dramatic inhibitory effect. These findings are discussed in light of the disappointing clinical utility of baclofen and neurokinin-1 receptor antagonists to combat pain.
Copyright © 2000 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.