Premium
Neonatal isolation accelerates the developmental switch in the signalling cascades for long‐term potentiation induction
Author(s) -
Huang ChiungChun,
Chou PeiHsuan,
Yang ChihHao,
Hsu KueiSen
Publication year - 2005
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1113/jphysiol.2005.098160
Subject(s) - long term potentiation , protein kinase a , biology , hippocampal formation , medicine , endocrinology , ltp induction , antagonist , hippocampus , kinase , receptor , neuroscience , microbiology and biotechnology
The molecular mechanisms underlying long‐term potentiation (LTP) in the CA1 region of the hippocampus are known to vary with developmental age. The physiological factors regulating this developmental change, however, have not yet been elucidated. Here we show that mild neonatal isolation accelerates the developmental switch in the signalling cascades for hippocampal CA1 LTP induction from a cyclic AMP‐dependent protein kinase (PKA)‐ to a Ca 2 + /calmodulin‐dependent protein kinase II (CaMKII)‐dependent pattern via the activation of the corticotrophin‐releasing factor (CRF) system. Furthermore, this action appears to be mediated through an increased transcription of the α isoform of the CaMKII ( CaMKII α) gene. We also demonstrate that application of CRF to cultured hippocampal neurones significantly increases the expression of CaMKII α, which is blocked by the non‐specific CRF receptor antagonist astressin, the specific CRF receptor 1 antagonist NBI 27911, and the PKA inhibitor KT5720, but not by the CRF receptor 2 antagonist K 41498, or the protein kinase C inhibitor, bisindolylmaleimide I. CRF signalling also mediates the normal maturation of LTP. These results suggest a novel role for CRF in regulating early developmental events in the hippocampus, and indicate that, although maternal deprivation is stressful for the neonate, appropriate neonatal isolation can serve to promote an endocrine state that fosters the rate of maturation of the signalling cascades underlying the induction of LTP in the developing hippocampus.