Specific high molecular weight mRNAs induced by associative learning in Hermissenda.

Nelson, Thomas; Alkon, Daniel L.

doi:10.1073/pnas.87.1.269

Cited by 20 publications

(3 citation statements)

References 20 publications

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“…Conditioning, but not random presentation of CS and US, was shown to be correlated with RNA changes maximal at 24 h and still detectable after 4 days [117]. Increases appeared in at least 21 high molecular weight mRNAs [118]. An increase in a specific G protein (cp20) in conditioned but not in control animals could also be detected 24 h after training using highperformance liquid chromatography [119].…”

Section: Memory Formation In Invertebratesmentioning

confidence: 90%

Memory formation and the regulation of gene expression

Stork

Welzl

1999

Cellular and Molecular Life Sciences (CMLS)

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On a cellular level, formation of memory is based on a selective change in synaptic efficacy that is both fast and, in case of important information, long-lasting. Rapidity of cellular changes is achieved by modifying preexisting synaptic molecules (receptors, ion channels), which instantaneously alters the efficacy of synaptic transmission. Endurance, that is the formation of long-term memory (LTM), is based on transient and perhaps also long-lasting changes in protein synthesis. A number of different methods exist to interfere with the synthesis of specific proteins or proteins in general. Other methods, in turn, help to identify proteins whose synthesis is changed following learning. These mostly molecular methods are briefly described in the present review. Their successful application in a variety of memory paradigms in invertebrates and vertebrates is illustrated. The data support the importance of selective changes in gene expression for LTM. Proteins newly synthesized during memory consolidation are likely to contribute to restructuring processes at the synapse. altering the efficiency of transmission beyond the scope of STM. Increased or, less often, decreased synthesis of proteins appears during specific time windows following learning. Recent evidence supports older data suggesting that two or even more waves of protein synthesis exist during the consolidation period. It is expected that the new molecular methods will help to identify and characterize molecules whose expression changes during LTM formation even in complex vertebrate learning paradigms.

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Section: Memory Formation In Invertebratesmentioning

confidence: 90%

Memory formation and the regulation of gene expression

Stork

Welzl

1999

Cellular and Molecular Life Sciences (CMLS)

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“…The short-and long-term facilitation in Aplysia caused by cAMP cascade required the prolongation of an action potential and a de novo protein synthesis, respectively (Siegelbaum et al, 1982;Sweatt and Kandel, 1989;Hochner and Kandel, 1992;Schacher et al, 1993;O'Leary et al, 1995;Sugita et al, 1997;Abel and Kandel, 1998). Even in the CNS of Hermissenda in which intracellular Ca 2+ plays an important role in the signal transduction (Alkon et al, 1992;Ito et al, 1994), the longlasting depolarization due to a reduction in K + -channel conductance and the increase in specific mRNA were reported in the synaptic enhancement in a classical conditioning (Alkon et al, 1985;Nelson and Alkon, 1990). To gain a deeper insight into the excitability of the presynaptic CGC, the duration of the current-evoked and the spontaneous spikes at 30% and 70% from their bottoms were also examined (see the methods in Klein (1993).…”

Section: Discussionmentioning

confidence: 99%

PKA-Dependent Regulation of Synaptic Enhancement between a Buccal Motor Neuron and Its Regulatory Interneuron in Lymnaea stagnalis

Nakamura¹,

Kobayashi²,

Kojima³

et al. 1999

Zoological Science

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ABSTRACT-The cerebral giant cell (CGC) is known to play a crucial role in the regulation of feeding response in the pond snail, Lymnaea stagnalis. However, the mechanisms of signal transduction from the CGC to the following buccal motor neurons are not clear. In the present study, we examined whether cyclic AMP (cAMP)-dependent protein kinase (PKA) contributes to enhancement of a monosynaptic connection between the presynaptic CGC and the postsynaptic buccal motor neuron 1 (B1 cell). Injection of cAMP into the CGC or inhibition of phosphodiesterase by isobutylmethylxanthine in the CGC increased the amplitude of excitatory postsynaptic potential (EPSP) in the B1 cell, whereas no changes were detected in the electrical properties of the CGC. The synaptic enhancement in the B1 cell was completely blocked by inhibition of PKA in the CGC but did not require a de novo protein synthesis due to a PKA phosphorylation. The increase in the EPSP amplitude of B1 cell was associated with the increase in the amount of serotonin release from the CGC. These results hence provided the physiological evidence of the direct regulation of a synaptic enhancement by PKA in the CNS of L. stagnalis, indicating the completely different mechanism from that in the well-studied siphon-and gill-withdrawal reflex in Aplysia.

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“…More recently, the use of models for learning that can be studied at both the behavioral and molecular levels indicates changes in gene transcription are required for the induction of longterm memory (Nelson and Alkon 1990;Anokhin and Rose 1991;Bourtchuladze et al 1994;Yin et al 1994). Additional evidence for the involvement of transcription has come from studying sensitization, a form of nonassociative learning, in Aplysia.…”

Section: Introductionmentioning

confidence: 99%

Identification of specific mRNAs affected by treatments producing long-term facilitation in Aplysia.

Zwartjes

West

Hattar³

et al. 1998

Learn. Mem.

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Neural correlates of long-term sensitization of defensive withdrawal reflexes in Aplysia occur in sensory neurons in the pleural ganglia and can be mimicked by exposure of these neurons to serotonin (5-HT). Studies using inhibitors indicate that transcription is necessary for production of long-term facilitation by 5-HT. Several mRNAs that change in response to 5-HT have been identified, but the molecular events responsible for long-term facilitation have not yet been fully described. To detect additional changes in mRNAs, we investigated the effects of 5-HT (1.5 hr) on levels of mRNA in pleural-pedal ganglia using in vitro translation. Four mRNAs were affected by 5-HT, three of which were identified as calmodulin (CaM), phosphoglycerate kinase (PGK), and a novel gene product (protein 3). Using RNase protection assays, we found that 5-HT increased all three mRNAs in the pleural sensory neurons. CaM and protein 3 mRNAs were also increased in the sensory neurons 4Corresponding author.by sensitization training. Furthermore, stimulation of peripheral nerves of pleural-pedal ganglia, an in vitro analog of sensitization training, increased the incorporation of labeled amino acids into CaM, PGK, and protein 3. These results indicate that increases in CaM, PGK, and protein 3 are part of the early response of sensory neurons to stimuli that produce long-term facilitation, and that CaM and protein 3 could have a role in the generation of long-term sensitization.

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Specific high molecular weight mRNAs induced by associative learning in Hermissenda.

Cited by 20 publications

References 20 publications

Memory formation and the regulation of gene expression

Memory formation and the regulation of gene expression

PKA-Dependent Regulation of Synaptic Enhancement between a Buccal Motor Neuron and Its Regulatory Interneuron in Lymnaea stagnalis

Identification of specific mRNAs affected by treatments producing long-term facilitation in Aplysia.

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