Multiple Forms of Long-Term Potentiation and Long-Term Depression Converge on a Single Interneuron in the Leech CNS
Open Access
- 21 April 2004
- journal article
- Published by Society for Neuroscience in Journal of Neuroscience
- Vol. 24 (16), 4011-4019
- https://doi.org/10.1523/jneurosci.0178-04.2004
Abstract
Long-term potentiation (LTP) of synaptic transmission was observed in two types of synapses that converge on the same postsynaptic neuron in the leech CNS. These synapses were made by identifiable sensory neurons, the mechanosensory touch (T-) and pressure (P-) cells, onto the S-cell, an interneuron critical for certain forms of learning. Changes in both the T-S and P-S synapses appear to be activity dependent because LTP was restricted to inputs that had undergone tetanization; however, properties of synaptic plasticity at the T-S and P-S connections differ considerably. At the P-S synapse, LTP was induced in the tetanized synapse but not in the nontetanized synapse tested in parallel. P-S LTP was blocked by the NMDA receptor antagonistdl-2-amino-5-phosphono-valeric acid (AP-5) or by lowering the extracellular concentration of glycine, an NMDA receptor (NMDAR) co-agonist. P-S LTP was strongly affected by the initial amplitude of the synaptic potential at the time LTP was induced. Smaller amplitude synapses (3.5 mV) depressed after tetanization. At the T-S synapse, tetanization simultaneously induced homosynaptic LTP in the tetanized input and heterosynaptic long-term depression (LTD) in the input made by a nontetanized T-cell onto the same S-cell. Interestingly, AP-5 failed to block homosynaptic LTP at the T-S synapse but did prevent heterosynaptic LTD. T-S LTP was not affected by the initial EPSP amplitude. Thus, leech neurons exhibit synaptic plasticity with properties similar to LTP and LTD found in the vertebrate nervous system.This publication has 63 references indexed in Scilit:
- Progressive recovery of learning during regeneration of a single synapse in the medicinal leechJournal of Comparative Neurology, 2003
- Evidence against the presence of NMDA receptors at a central glutamatergic synapse in leechesInvertebrate Neuroscience, 2002
- Synaptic Modification by Correlated Activity: Hebb's Postulate RevisitedAnnual Review of Neuroscience, 2001
- Mediation of Classical Conditioning in Aplysia californica by Long-Term Potentiation of Sensorimotor SynapsesScience, 1997
- Cyclic AMP Mediates a Presynaptic Form of LTP at Cerebellar Parallel Fiber SynapsesNeuron, 1996
- Long-term potentiation of Aplysia sensorimotor synapses in cell culture: regulation by postsynaptic voltageProceedings. Biological sciences, 1994
- Glutamate receptors of Drosophila melanogasterFEBS Letters, 1993
- Homo‐ and heterosynaptic changes in efficacy are expressed in prefrontal neurons: An in vitro study in the ratSynapse, 1992
- Activity-Dependent Synaptic Competition in Vitro: Heterosynaptic Suppression of Developing SynapsesScience, 1991
- Long‐term potentiation in hippocampal CA3 neurons: Tetanized input regulates heterosynaptic efficacySynapse, 1989