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Differential role of hippocampal cAMP-dependent protein kinase in short- and long-term memory.
- Source :
-
Neurochemical research [Neurochem Res] 2000 May; Vol. 25 (5), pp. 621-6. - Publication Year :
- 2000
-
Abstract
- One-trial step-down inhibitory (passive) avoidance training is followed by two peaks of cAMP-dependent protein kinase (PKA) activity in rat CA1: one immediately after training and the other 3 h later. The second peak relies on the first: Immediate posttraining infusion into CA1 of the inhibitor of the regulatory subunit of PKA, Rp-cAMPS, at a dose that reduces PKA activity during less than 90 min, cancelled both peaks. Long-term memory (LTM) of this task measured at 24 h depends on the two peaks: Rp-cAMPS given into CA1 0 or 175 min posttraining, but not between those times, blocked LTM. However, the effect of immediate posttraining Rp-cAMPS on LTM could not be reversed by the activator of the regulatory subunit of PKA, Sp-cAMPS, given at 180 min, which suggests that, for LTM, the first peak may be more important than the second. When given at 0, 22, 45, or 90, but not at 175 min from training, Rp-cAMPS blocked short-term memory (STM) measured at 90 or 180 min. This effect of immediate posttraining Rp-cAMPS infusion on STM but not that on LTM was readily reversed by Sp-cAMPS infused 22 min later. On its own, Sp-cAMPS had effects exactly opposite to those of the inhibitor. It enhanced LTM when given at 0 or 175 min from training, and it enhanced STM when given at 0, 22, 45, or 90 min from training. These findings show that STM and LTM formation require separate PKA-dependent processes in CA1. STM relies on the continued activity of the enzyme during the first 90 min. LTM relies on the two peaks of PKA activity that occur immediately and 180 min posttraining.
- Subjects :
- Animals
Avoidance Learning drug effects
Cyclic AMP administration & dosage
Cyclic AMP pharmacology
Electroshock
Enzyme Inhibitors administration & dosage
Enzyme Inhibitors pharmacology
Hippocampus drug effects
Hippocampus enzymology
Infusions, Parenteral
Memory drug effects
Memory, Short-Term drug effects
Neurons drug effects
Neurons enzymology
Neurons physiology
Rats
Rats, Wistar
Thionucleotides administration & dosage
Time Factors
Avoidance Learning physiology
Cyclic AMP analogs & derivatives
Cyclic AMP-Dependent Protein Kinases metabolism
Hippocampus physiology
Memory physiology
Memory, Short-Term physiology
Thionucleotides pharmacology
Subjects
Details
- Language :
- English
- ISSN :
- 0364-3190
- Volume :
- 25
- Issue :
- 5
- Database :
- MEDLINE
- Journal :
- Neurochemical research
- Publication Type :
- Academic Journal
- Accession number :
- 10905623
- Full Text :
- https://doi.org/10.1023/a:1007502918282