Journal of Neuroscience, Vol 14, 2282-2289, Copyright © 1994 by Society for Neuroscience
Relationship of APP mRNA transcripts and levels of NGF and low-affinity NGF receptors to behavioral measures of age-related cognitive dysfunction
MD Lindner, SI Dworetzky, C Sampson and R Loy
University of Rochester School of Medicine, Monroe Community Hospital, New York 14620.
This study was designed to examine the relationship between cognitive
function and endogenous levels of NGF, low-affinity NGF receptor (LNGFR),
and amyloid precursor protein (APP) mRNAs. Using 3 month (n = 5), 18 month
(n = 40), and 29 month (n = 17) Fischer-344 male rats, cognitive function
was assessed with the Morris water maze, reverse transcription and
polymerase chain reaction were used to quantify APP mRNAs, and NGF and
LNGFR levels were determined with an ELISA. Cognitive function declined
progressively with age from 3 months to 18 months, and from 18 months to 29
months, but only RNA content in the tissue declined significantly from 3
months to 18 months. Between 18 month and 29 month rats were small but
statistically significant decreases only for Kunitz protease inhibitor
(KPI)-inclusive mRNAs and cortical NGF levels. There was a small but
statistically significant correlation between cognitive function and %KPI
(the amount of KPI APP mRNAs relative to the total amount of APP mRNA),
with lower %KPI related to more impaired spatial learning. No other
statistically significant correlation or linear relationship could be
detected between cognitive function and any of the other neurological
measures or any combination of these measures (i.e., hippocampal levels of
APP 695 mRNA, cortical and hippocampal levels of NGF, and cortical,
hippocampal, and basal forebrain levels of LNGFR).(ABSTRACT TRUNCATED AT
250 WORDS)