Hsp70 mRNA induction is reduced in neurons of aged rat hippocampus after thermal stress.
Levels of heat-shock 70 mRNAs, relative to those of 18S rRNA, were quantitated in specific cell types of hippocampus of adult and aged rats subjected to identical heat shock regimens. Body temperature changes in response to the heat stress were no different in adult and aged rats. In control rats, as well as 3 h after initiation of heat shock in both adult and aged rats, relative levels of the constitutively synthesized heat-shock cognate 70 (hsc70) mRNA were highest in hippocampal neurons and much lower in glia. No heat-shock protein 70 (hsp70) mRNAs were present in any cell type of control adult or aged rats. In heat-shocked adult rats, the relative levels of the heat-shock-inducible hsp70 mRNAs were highest in a subpopulation of glia, intermediate in granule cells of the dentate gyrus, and lowest in pyramidal cells of Ammon's horn. Relative levels of hsp70 mRNA were several-fold lower in the dentate gyrus granule cells of aged rats compared to relative levels in controls and were also reduced in many pyramidal cells of the hippocampus but not in hippocampal glia. These findings suggest that some neuronal populations in the hippocampus may be at increased risk for stress-related injury in the aged animal.
Pardue
S
S
Schizophrenia Research Center, Veterans Administration Medical Center, Dallas, TX.
Groshan
K
K
Raese
J D
JD
Morrison-Bogorad
M
M
D000375:Aging / Q000378:metabolism*; D000818:Animals; D006360:Heat-Shock Proteins / Q000378:metabolism*; D006624:Hippocampus / Q000033:anatomy & histology / Q000166:cytology / Q000378:metabolism*; D006358:Hot Temperature; D017403:In Situ Hybridization; D008297:Male; D009474:Neurons / Q000378:metabolism*; D009841:Oligonucleotides / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis*; D051381:Rats; D011916:Rats, Inbred F344; D013315:Stress, Psychological / Q000378:metabolism
D006360:Heat-Shock Proteins; D009841:Oligonucleotides; D012333:RNA, Messenger