Chronic stress induces changes in the structure of interneurons and in the expression of molecules related to neuronal structural plasticity and inhibitory neurotransmission in the amygdala of adult mice

• Published in: Experimental neurology 2011-11, Vol.232 (1), p.33-40
• Main Authors: Gilabert-Juan, Javier, Castillo-Gomez, Esther, Pérez-Rando, Marta, Moltó, María Dolores, Nacher, Juan
• Format: Article
• Language: English
• Subjects: Amygdala - metabolism; Amygdala - pathology; Animals; Biological and medical sciences; Dendrites - metabolism; Dendrites - pathology; Dendritic Spines - metabolism; Dendritic Spines - pathology; Development. Senescence. Regeneration. Transplantation; Disease Models, Animal; Fundamental and applied biological sciences. Psychology; Glutamate Decarboxylase - genetics; Glutamate Decarboxylase - metabolism; Glutamic acid decarboxylase; Immobilization; Immunohistochemistry; Interneuron; Interneurons - metabolism; Interneurons - pathology; Male; Medical sciences; Mice; Neural Cell Adhesion Molecule L1 - genetics; Neural Cell Adhesion Molecule L1 - metabolism; Neurology; Neuronal Plasticity; Polysialyltransferase; Sialic Acids - genetics; Sialic Acids - metabolism; Sialyltransferases - genetics; Sialyltransferases - metabolism; Stress, Psychological - metabolism; Stress, Psychological - pathology; Synaptic Transmission; Synaptophysin; Synaptophysin - metabolism; Vertebrates: nervous system and sense organs
• ISSN: 0014-4886; 1090-2430
• DOI: 10.1016/j.expneurol.2011.07.009

Chronic stress in experimental animals, one of the most accepted models of chronic anxiety and depression, induces structural remodeling of principal neurons in the amygdala and increases its excitation by reducing inhibitory tone. These changes may be mediated by the polysialylated form of the neural cell adhesion molecule (PSA-NCAM), a molecule related to neuronal structural plasticity and expressed by interneurons in the adult CNS, which is downregulated in the amygdala after chronic stress. We have analyzed the amygdala of adult mice after 21 days of restraint stress, studying with qRT-PCR the expression of genes related to general and inhibitory neurotransmission, and of PSA synthesizing enzymes. The expression of GAD67, synaptophysin and PSA-NCAM was also studied in specific amygdaloid nuclei using immunohistochemistry. We also analyzed dendritic arborization and spine density, and cell activity, monitoring c-Fos expression, in amygdaloid interneurons. At the mRNA level, the expression of GAD67 and of St8SiaII was significantly reduced. At the protein level there was an overall reduction in the expression of GAD67, synaptophysin and PSA-NCAM, but significant changes were only detected in specific amygdaloid regions. Chronic stress did not affect dendritic spine density, but reduced dendritic arborization in interneurons of the lateral and basolateral amygdala. These results indicate that chronic stress modulates inhibitory neurotransmission in the amygdala by regulating the expression of molecules involved in this process and by promoting the structural remodeling of interneurons. The addition of PSA to NCAM by St8SiaII may be involved in these changes. ► Chronic stress decreases inhibitory tone and induces structural changes in amygdala. ► Molecules related to inhibition/structural plasticity involved in this plasticity? ► We subjected mice subjected to 21 days of restraint stress. ► Reductions in expression of GAD67 and St8SiaII mRNA and GAD67, synaptophysin and PSA-NCAM protein. ► Reduced dendritic arborization in interneurons of the lateral and basolateral amygdala.