title: Actions of Steroids: New Neurotransmitters.
abstract: Over the past two decades, the classical understanding of steroid action has been updated to include rapid, membrane-initiated, neurotransmitter-like functions. While steroids were known to function on very short time spans to induce physiological and behavioral changes, the mechanisms by which these changes occur are now becoming more clear. In avian systems, rapid estradiol effects can be mediated via local alterations in aromatase activity, which precisely regulates the temporal and spatial availability of estrogens. Acute regulation of brain-derived estrogens has been shown to rapidly affect sensorimotor function and sexual motivation in birds. In rodents, estrogens and progesterone are critical for reproduction, including preovulatory events and female sexual receptivity. Membrane progesterone receptor as well as classical progesterone receptor trafficked to the membrane mediate reproductive-related hypothalamic physiology, via second messenger systems with dopamine-induced cell signals. In addition to these relatively rapid actions, estrogen membrane-initiated signaling elicits changes in morphology. In the arcuate nucleus of the hypothalamus, these changes are needed for lordosis behavior. Recent evidence also demonstrates that membrane glucocorticoid receptor is present in numerous cell types and species, including mammals. Further, membrane glucocorticoid receptor influences glucocorticoid receptor translocation to the nucleus effecting transcriptional activity. The studies presented here underscore the evidence that steroids behave like neurotransmitters to regulate CNS functions. In the future, we hope to fully characterize steroid receptor-specific functions in the brain.
authors.affiliation: Department of Neurobiology and Laboratory of Neuroendocrinology, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, California 90095, lrudolph@mednet.ucla.edu.
authors.forename: Lauren M
authors.identifier: 0000-0002-4798-2457
authors.initials: LM
authors.lastname: Rudolph
authors.affiliation: Behavioral Neuroendocrinology Group, GIGA Neurosciences, University of Liège, 4000 Liege, Belgium.
authors.forename: Charlotte A
authors.identifier: 0000-0002-5536-7753
authors.initials: CA
authors.lastname: Cornil
authors.affiliation: Department of Neurobiology and Laboratory of Neuroendocrinology, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, California 90095.
authors.forename: Melinda A
authors.initials: MA
authors.lastname: Mittelman-Smith
authors.affiliation: Department of Cell and Molecular Biology, Tulane University, New Orleans, Louisiana 70118.
authors.forename: Jennifer R
authors.identifier: 0000-0003-2527-8175
authors.initials: JR
authors.lastname: Rainville
authors.affiliation: Department of Psychological and Brain Sciences, Center for Neuroendocrine Studies, University of Massachusetts, Amherst, Massachusetts 01003, and.
authors.forename: Luke
authors.initials: L
authors.lastname: Remage-Healey
authors.affiliation: Department of Biological Sciences, California State University, Long Beach, Long Beach, California 90840.
authors.forename: Kevin
authors.identifier: 0000-0001-8843-4708
authors.initials: K
authors.lastname: Sinchak
authors.affiliation: Department of Neurobiology and Laboratory of Neuroendocrinology, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, California 90095.
authors.forename: Paul E
authors.identifier: 0000-0002-9577-5874
authors.initials: PE
authors.lastname: Micevych
mesh_terms: D000818:Animals; D001921:Brain / Q000502:physiology*; D019317:Evidence-Based Medicine; D006801:Humans; D008959:Models, Neurological; D018377:Neurotransmitter Agents / Q000378:metabolism*; D015290:Second Messenger Systems / Q000502:physiology*; D013256:Steroids / Q000378:metabolism*; D009435:Synaptic Transmission / Q000502:physiology*
chemical_list: D018377:Neurotransmitter Agents; D013256:Steroids