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TitleGlucocorticoid feedback uncovers retrograde opioid signaling at hypothalamic synapses.
Publication TypeJournal Article
Year of Publication2013
AuthorsCusulin, Jaclyn I. Wamsteek, Tamás Füzesi, Wataru Inoue, and Jaideep S. Bains
JournalNat Neurosci
Date Published2013 May
KeywordsAnalgesics, Opioid, Animals, Animals, Newborn, Bacterial Proteins, Enzyme Inhibitors, Feedback, Physiological, Glucocorticoids, Hypothalamus, In Vitro Techniques, Inhibitory Postsynaptic Potentials, Luminescent Proteins, Male, Mice, Mice, Inbred C57BL, Mice, Transgenic, Neurotransmitter Agents, Rats, Rats, Sprague-Dawley, Receptor, Cannabinoid, CB1, Receptors, Glucocorticoid, Receptors, Opioid, mu, Rhodopsin, Signal Transduction, Stress, Psychological, Synapses, Vesicular Inhibitory Amino Acid Transport Proteins

Stressful experience initiates a neuroendocrine response culminating in the release of glucocorticoid hormones into the blood. Glucocorticoids feed back to the brain, causing adaptations that prevent excessive hormone responses to subsequent challenges. How these changes occur remains unknown. We found that glucocorticoid receptor activation in rodent hypothalamic neuroendocrine neurons following in vivo stress is a metaplastic signal that allows GABA synapses to undergo activity-dependent long-term depression (LTDGABA). LTDGABA was unmasked through glucocorticoid receptor-dependent inhibition of Regulator of G protein Signaling 4 (RGS4), which amplified signaling through postsynaptic metabotropic glutamate receptors. This drove somatodendritic opioid release, resulting in a persistent retrograde suppression of synaptic transmission through presynaptic μ receptors. Together, our data provide new evidence for retrograde opioid signaling at synapses in neuroendocrine circuits and represent a potential mechanism underlying glucocorticoid contributions to stress adaptation.

Alternate JournalNat. Neurosci.
PubMed ID23563581
Grant ListMOP 86501 / / Canadian Institutes of Health Research / Canada