Elevated dynorphin in the hippocampal formation of aged rats: relation to cognitive impairment on a spatial learning task.
Radioimmunoassay revealed increased dynorphin A(1-8)-like immunoreactivity [dynA(1-8)LI] in the aged rat brain. Among a number of brain regions examined, an age-related dynA(1-8)LI elevation was found only in the hippocampal formation and frontal cortex. Moreover, the increase in dynA(1-8)LI in the aged hippocampus was associated with a decline in spatial learning ability: dynA(1-8)LI distinguished aged rats that were behaviorally impaired from aged cohorts that learned the spatial task as rapidly as younger animals. Northern blot hybridization using a 32P-labeled complementary RNA probe encoding rat prodynorphin indicated that the abundance of prodynorphin mRNA was also significantly increased in the hippocampal formation of aged rats with identified spatial learning impairments.
Jiang
H K
HK
Department of Psychology, University of North Carolina, Chapel Hill 27599-3270.
Owyang
V V
VV
Hong
J S
JS
Gallagher
M
M
D000375:Aging; D000818:Animals; D015152:Blotting, Northern; D003071:Cognition / Q000502:physiology*; D004399:Dynorphins / Q000502:physiology*; D004745:Enkephalins / Q000235:genetics; D006624:Hippocampus / Q000502:physiology*; D007858:Learning / Q000502:physiology*; D011498:Protein Precursors / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats
D004745:Enkephalins; D011498:Protein Precursors; D012333:RNA, Messenger; D004399:Dynorphins; C033660:preproenkephalin