Converging, Synergistic Actions of Multiple Stress Hormones Mediate Enduring Memory Impairments after Acute Simultaneous Stresses.
Stress influences memory, an adaptive process crucial for survival. During stress, hippocampal synapses are bathed in a mixture of stress-released molecules, yet it is unknown whether or how these interact to mediate the effects of stress on memory. Here, we demonstrate novel synergistic actions of corticosterone and corticotropin-releasing hormone (CRH) on synaptic physiology and dendritic spine structure that mediate the profound effects of acute concurrent stresses on memory. Spatial memory in mice was impaired enduringly after acute concurrent stresses resulting from loss of synaptic potentiation associated with disrupted structure of synapse-bearing dendritic spines. Combined application of the stress hormones corticosterone and CRH recapitulated the physiological and structural defects provoked by acute stresses. Mechanistically, corticosterone and CRH, via their cognate receptors, acted synergistically on the spine-actin regulator RhoA, promoting its deactivation and degradation, respectively, and destabilizing spines. Accordingly, blocking the receptors of both hormones, but not each alone, rescued memory. Therefore, the synergistic actions of corticosterone and CRH at hippocampal synapses underlie memory impairments after concurrent and perhaps also single, severe acute stresses, with potential implications to spatial memory dysfunction in, for example, posttraumatic stress disorder.



Stress influences memory, an adaptive process crucial for survival. During stress, adrenal corticosterone and hippocampal corticotropin-releasing hormone (CRH) permeate memory-forming hippocampal synapses, yet it is unknown whether (and how) these hormones interact to mediate effects of stress. Here, we demonstrate novel synergistic actions of corticosterone and CRH on hippocampal synaptic plasticity and spine structure that mediate the memory-disrupting effects of stress. Combined application of both hormones provoked synaptic function collapse and spine disruption. Mechanistically, corticosterone and CRH synergized at the spine-actin regulator RhoA, promoting its deactivation and degradation, respectively, and destabilizing spines. Notably, blocking both hormones, but not each alone, prevented the enduring memory problems after acute concurrent stresses. Therefore, synergistic actions of corticosterone and CRH underlie enduring memory impairments after concurrent acute stresses, which might be relevant to spatial memory deficits described in posttraumatic stress disorder.
Department of Anatomy/Neurobiology, tallie@uci.edu yuncaic@uci.edu.|Department of Pediatrics, and.
Yuncai
Y
Chen
Department of Anatomy/Neurobiology.
Jenny
J
Molet
Department of Anatomy/Neurobiology.
Julie C
JC
Lauterborn
Department of Anatomy/Neurobiology.
Brian H
0000-0002-2201-090X
BH
Trieu
Department of Anatomy/Neurobiology.|Department of Pediatrics, and.
Jessica L
0000-0002-8872-4999
JL
Bolton
Department of Anatomy/Neurobiology.
Katelin P
KP
Patterson
Department of Anatomy/Neurobiology.
Christine M
CM
Gall
Department of Anatomy/Neurobiology.
Gary
G
Lynch
Department of Anatomy/Neurobiology, tallie@uci.edu yuncaic@uci.edu.|Department of Pediatrics, and.|Department of Neurology, University of California-Irvine, Irvine, California 92697.
Tallie Z
TZ
Baram
D000208:Acute Disease; D000818:Animals; D003345:Corticosterone / Q000008:administration & dosage / Q000378:metabolism*; D003346:Corticotropin-Releasing Hormone / Q000008:administration & dosage / Q000378:metabolism*; D004357:Drug Synergism; D006624:Hippocampus / Q000187:drug effects / Q000503:physiopathology*; D008297:Male; D008569:Memory Disorders / Q000209:etiology / Q000503:physiopathology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009473:Neuronal Plasticity; D065852:Spatial Memory; D013315:Stress, Psychological / Q000150:complications / Q000503:physiopathology*
D003346:Corticotropin-Releasing Hormone; D003345:Corticosterone
RhoGTPase; acute stress; dendritic spine; hippocampus; long-term potentiation; memory