Estrogen replacement increases spinophilin-immunoreactive spine number in the prefrontal cortex of female rhesus monkeys.
While studies have shown that estrogen affects hippocampal spine density and function, behavioral studies in humans and nonhuman primates have also implicated the prefrontal cortex in the effects of estrogen on cognition. However, the potential for similar estrogen-induced increases in spines and synapses in the prefrontal cortex has not been investigated in primates. Moreover, it is not known if such an estrogen effect would be manifested throughout the neocortex or primarily in the regions involved in cognition. Therefore, we investigated the effects of estrogen on dendritic spines in the prefrontal and primary visual cortices of young rhesus monkeys. Young female monkeys were ovariectomized and administered either estradiol cypionate or vehicle by intramuscular injection. Using an antibody against the spine-associated protein, spinophilin, spine numbers were estimated in layer I of area 46 and in layer I of the opercular portion of area V1 (V1o). Spine numbers in layer I of area 46 were significantly increased (55%) in the ovariectomy + estrogen group compared to the ovariectomy + vehicle group, yet spine numbers in layer I of area V1o were equivalent across the two groups. The present results suggest that estrogen's effects on synaptic organization influence select neocortical layers and regions in a primate model, and provide a morphological basis for enhanced prefrontal cortical functions following estrogen replacement.
Tang
Yong
Y
Kastor Neurobiology of Aging Laboratories and Fishberg Research Center for Neurobiology, Mount Sinai School of Medicine, New York, NY 10029, USA.
Janssen
William G M
WG
Hao
Jiandong
J
Roberts
Jeffrey A
JA
McKay
Heather
H
Lasley
Bill
B
Allen
Patrick B
PB
Greengard
Paul
P
Rapp
Peter R
PR
Kordower
Jeffrey H
JH
Hof
Patrick R
PR
Morrison
John H
JH
D000818:Animals; D002452:Cell Count / Q000379:methods; D003712:Dendrites / Q000737:chemistry* / Q000187:drug effects*; D004958:Estradiol / Q000494:pharmacology*; D015914:Estrogen Replacement Therapy / Q000379:methods*; D005260:Female; D007150:Immunohistochemistry; D008253:Macaca mulatta; D008840:Microfilament Proteins / Q000032:analysis*; D009419:Nerve Tissue Proteins / Q000032:analysis*; D010052:Ovariectomy; D017397:Prefrontal Cortex / Q000737:chemistry / Q000166:cytology* / Q000187:drug effects*; D000099273:Neurabins
D004958:Estradiol; D008840:Microfilament Proteins; D009419:Nerve Tissue Proteins; D000099273:Neurabins