Insulin-like growth factor-1 does not ameliorate the age-related decline in presumptive inhibitory synapses in layer 2 of rat sensorimotor cortex.
Four old (29 months) Brown Norway x Fischer 344 (BN x F344) rats received intracerebroventricular infusion of insulin-like growth factor-1 (IGF-1) and four middle-aged (18 months) and four old (29 months) rats received infusion of saline for 28 days. Sensorimotor cortex containing layer 2 was blocked and processed for electron microscopy. Thin (700 A) and semithin (1 microm) sections were collected from the same anatomical space for quantification of synapses and neurons, respectively, using the physical disector. Numerical density (Nv) of presumptive inhibitory synapses in layer 2 of sensorimotor cortex has been reported to decline with age Poe et al., 2001; Brunso-Bechtold et al. [Brain Res. 872 (2000) 125]. Infusion of IGF-1 did not affect the density of synapses or neurons when old IGF-1 animals were compared with old saline animals.
Poe
Brandon H
BH
Neuroscience Program, Wake Forest University School of Medicine, Winston-Salem, NC, USA. bpoe@ravenbrand.com
Linville
M Constance
MC
Sonntag
William E
WE
Brunso-Bechtold
Judy K
JK
D000375:Aging / Q000502:physiology*; D000818:Animals; D002552:Cerebral Ventricles / Q000187:drug effects / Q000502:physiology; D007263:Infusions, Parenteral; D007334:Insulin-Like Growth Factor I / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000648:ultrastructure; D051381:Rats; D011914:Rats, Inbred BN; D011916:Rats, Inbred F344; D012016:Reference Values; D013003:Somatosensory Cortex / Q000187:drug effects / Q000254:growth & development* / Q000648:ultrastructure; D013569:Synapses / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure
D007334:Insulin-Like Growth Factor I