Synaptic activity-dependent modulation of mitochondrial gene expression in the rat hippocampus.
In order to identify genes that may underlie the maintenance of long-term potentiation (LTP) at perforant path synapses, complementary DNA libraries were synthesised from dentate gyrus total RNA extracts prepared 48 h after the induction of LTP and from control dentate gyrus extracts. Through differential screening of the LTP library we have identified the mitochondrial 12S rRNA (mt12SrRNA) as a transcript that was elevated at this late time. Northern blot analyses showed that the elevation in mt12SrRNA expression began around 8 h and persisted for at least 2 weeks post-tetanus. We then examined the expression patterns of other mitochondrially-encoded genes and demonstrated a similar elevation in their expression. mt12SrRNA levels were also elevated in other hippocampal regions, including areas CA3 and CA1 and were elevated following low-frequency stimulation or in the presence of an N-methyl-D-aspartate receptor antagonist where induction of LTP was precluded. Taken together, these observations suggest that a long-lasting up-regulation of energy production may be triggered by synaptic activity and this activity need not be of sufficient strength to induce LTP, but may be related to the induction of a metaplastic state.
Williams
J M
JM
Department of Biochemistry and Centre for Gene Research, University of Otago, P.O. Box 56, Dunedin, New Zealand.
Thompson
V L
VL
Mason-Parker
S E
SE
Abraham
W C
WC
Tate
W P
WP
D000818:Animals; D018076:DNA, Complementary; D018891:Dentate Gyrus / Q000166:cytology* / Q000502:physiology; D015870:Gene Expression / Q000502:physiology; D015723:Gene Library; D017774:Long-Term Potentiation / Q000235:genetics*; D008297:Male; D008568:Memory / Q000502:physiology; D008928:Mitochondria / Q000235:genetics*; D009474:Neurons / Q000737:chemistry / Q000502:physiology*; D019580:Perforant Pathway / Q000166:cytology / Q000502:physiology; D012313:RNA / Q000032:analysis; D012333:RNA, Messenger / Q000032:analysis; D000077278:RNA, Mitochondrial; D012335:RNA, Ribosomal / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000502:physiology; D013569:Synapses / Q000502:physiology*; D015533:Transcriptional Activation / Q000502:physiology
D018076:DNA, Complementary; D012333:RNA, Messenger; D000077278:RNA, Mitochondrial; D012335:RNA, Ribosomal; C075526:RNA, ribosomal, 12S; D016194:Receptors, N-Methyl-D-Aspartate; D012313:RNA