Protection by prosaposin against ischemia-induced learning disability and neuronal loss.
Prosaposin, the protein precursor of saposins A, B, C, and D which activate sphingolipid hydrolases, is abundant in several brain regions including the hippocampus. We infused prosaposin continuously for 7 days into the lateral ventricle of gerbils starting 3 hours before 3-min of forebrain ischemia. Using the step-down passive avoidance task, we demonstrated that ischemia-induced learning disability is prevented almost completely by prosaposin infusion. Subsequent light and electron microscopic examinations showed that pyramidal neurons in the CA1 field of the hippocampus as well as synapses within the strata moleculare, lacunosum/radiatum and oriens of the field were significantly more numerous in gerbils infused with prosaposin infusion than in those receiving saline infusion. These findings suggest that prosaposin possesses neurotrotrophic activity to protect hippocampal CA1 neurons from lethal ischemic damage.
Department of Neuropsychiatry, Ehime University School of Medicine, Japan.
A
A
Sano
S
S
Matsuda
T C
TC
Wen
Y
Y
Kotani
K
K
Kondoh
S
S
Ueno
Y
Y
Kakimoto
H
H
Yoshimura
M
M
Sakanaka
D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects*; D002545:Brain Ischemia / Q000503:physiopathology*; D005849:Gerbillinae; D006023:Glycoproteins / Q000494:pharmacology*; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects; D008297:Male; D009474:Neurons / Q000187:drug effects; D011498:Protein Precursors / Q000494:pharmacology*; D049231:Saposins
D006023:Glycoproteins; D011498:Protein Precursors; D049231:Saposins