Single exposure to social defeat increases corticotropin-releasing factor and glucocorticoid receptor mRNA expression in rat hippocampus.
Stressful life events are able to induce long-term modifications in physiological and neuroendocrine parameters that are related to the onset of several psychiatric disorders. To gain information on molecular modifications involved in long-term changes triggered by stress, we evaluated gene expression in the hippocampus of rats exposed to a single social defeat session. In the social defeat model, the experimental animal is defeated by a dominant male. The defeat induced an increase in body temperature, in distress vocalisations, in serum corticosterone levels and in anxiety-related behaviour measured with an open field test applied 6 h after the exposure to the dominant rat. In the open field test, anxiety-related behaviours were not detectable anymore 30 h after the exposure to the dominant rat and mRNA levels were evaluated at this time-point. The mRNA levels of genes modulated by stress (corticotropin-releasing factor; corticotropin-releasing factor receptor 1; corticotropin-releasing factor binding protein; mineralocorticoid and glucocorticoid receptors; Ca2+/calmodulin-dependent protein kinase-like kinase; Krox20; Bcl-2) and control genes (glyceraldehyde-3-phosphate dehydrogenase; beta-actin and cyclophilin A) were measured with real-time reverse transcription polymerase chain reaction. Corticotropin-releasing factor and glucocorticoid receptor mRNA levels were significantly modulated by the stress procedure, both genes showing an increase in rats exposed to a social defeat. No expression level differences were detected for the other genes. In conclusion, we report that 30 h after an acute social stress, a modification in mRNA levels can be detected in rat hippocampus, thus suggesting potential candidate genes involved in mediating long-term responses.
Marini
Francesca
F
Department of Medicine and Public Health, Section of Pharmacology, University of Verona, Verona, Italy.
Pozzato
Chiara
C
Andreetta
Valentino
V
Jansson
Birger
B
Arban
Roberto
R
Domenici
Enrico
E
Carboni
Lucia
L
D000818:Animals; D001007:Anxiety / Q000235:genetics*; D017931:DNA Primers; D004291:Dominance-Subordination; D005784:Gene Amplification; D005786:Gene Expression Regulation; D006624:Hippocampus / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics*; D051381:Rats; D018019:Receptors, Corticotropin-Releasing Hormone / Q000235:genetics*; D011965:Receptors, Glucocorticoid / Q000235:genetics*; D012919:Social Behavior; D013315:Stress, Psychological; D014465:Ultrasonics; D014828:Vocalization, Animal
D017931:DNA Primers; D012333:RNA, Messenger; D018019:Receptors, Corticotropin-Releasing Hormone; D011965:Receptors, Glucocorticoid