Objective:To investigate the possible mechanisms in acupuncture analgesia by interaction of δ-opioid receptor with neurotransmitter transport proteins or the Na+-K+ pump.Methods:Microinjection of respective heterologous cRNA into the Xenopus oocytes as a model system,and measurement of steady-state currents under two-electrode voltage clamp.Results:The co-expression of the δ-opioid receptor with GAT1,EAAC1 or the sodium pump resulted in reducing activity of the respective transporter.Opioid receptor activation affected transporter activity in different ways: 1) GAT1 was further inhibited; 2) EAAC1 was stimulated;3)Na+-K+ pump activity interfered with agonist sensitivity of DOR.Pump inhibition led to higher sensitivity for DPDPE.Conclusion: GABA transporter inhibition and glutamate transporter stimulation may counteract pain sensation by affecting the neurotransmitter concentration in the synaptic cleft and,therefore,may contribute synergistically to pain suppression by acupuncture.Sodium pump inhibition by endogenous ouabain may amplify these effects.These synergistic effects may be the molecular mechanism of inhibiting pain sense and/or acupuncture analgesia.
Acupuncture Analgesia Receptors Opioid Neurotransmitter Transport Proteins Protein Interaction Domains and Motifs
YANG Zhi-jie BAO Guo-bin DENG Hai-ping DU Hui-ming GU Quan-bao PEI Gang PU Lu Wolfgang SCHWARZ XIA Peng
Max-Planck-Institute for Biophysics,Frankfurt/Main,Germany;Shanghai Research Center of Acupuncture a Max-Planck-Institute for Biophysics,Frankfurt/Main,Germany;MPG Guest Laboratory at the Partner Insti Shanghai Research Center of Acupuncture and Meridian,Shanghai 201203,P.R.China MPG Guest Laboratory at the Partner Institute of Computational Biology,Shanghai Institutes of Biolog Max-Planck-Institute for Biophysics,Frankfurt/Main,Germany;Shanghai Research Center of Acupuncture a