Hippocampal cell proliferation and spatial memory performance after social instability stress in adolescence in female rats.
We investigated the immediate and lasting effect of social instability stress in adolescence [SS: daily 1h isolation and change of cage partner postnatal days (P) 30-45] on cell proliferation in the hippocampus and on spatial memory using an object spatial location (SL) test. Female rats were treated with bromodeoxyuridine (BrdU) P43-45, and on P49, SS had reduced cell hippocampal cell proliferation/survival compared to controls as indicated by BrdU immunoreactive cell counts (p=0.009), and did not differ in Ki67 immunoreactive cell counts (p=0.15) from CTL. A separate group of SS and CTL rats were tested at P47 and P48, and again at P72 and P73 on the SL test using 1 and 8h retention intervals. SS and CTL females did not differ in adolescence, but CTL had better memory than SS as adults (p=0.03). The better memory performance of CTL rats is not due to differential investigation of objects during the familiarization pre-tests or by differential locomotor activity. The lasting memory reduction and reduced cell proliferation/survival in SS rats is consistent with the hypothesis that ongoing development of the hippocampus renders the adolescent particularly vulnerable to chronic social stress.
McCormick
Cheryl M
CM
Department of Psychology, Brock University, Canada. cmccormick@brocku.ca
Nixon
Feather
F
Thomas
Catherine
C
Lowie
Bobbi
B
Dyck
Joshua
J
D000704:Analysis of Variance; D000818:Animals; D000831:Animals, Newborn; D001973:Bromodeoxyuridine / Q000378:metabolism; D002452:Cell Count / Q000379:methods; D049109:Cell Proliferation; D005260:Female; D006624:Hippocampus / Q000473:pathology*; D019394:Ki-67 Antigen / Q000378:metabolism; D008569:Memory Disorders / Q000209:etiology*; D011897:Random Allocation; D051381:Rats; D020318:Rats, Long-Evans; D012934:Social Isolation / Q000523:psychology*; D013028:Space Perception / Q000502:physiology*; D013315:Stress, Psychological / Q000150:complications / Q000473:pathology / Q000523:psychology; D013997:Time Factors
D019394:Ki-67 Antigen; D001973:Bromodeoxyuridine