The effects of galanin on long-term synaptic plasticity in the CA1 area of rodent hippocampus.

Learning and memory involve complex changes in neuronal excitability including long-lasting synaptic plasticity of glutamatergic synapses. The observation that the neuropeptide galanin affects performance in a number of behavioural models predicts that galanin should affect synaptic processes underlying learning. The present study in rat and mouse hippocampal slices now demonstrates that galanin inhibits long-term potentiation induced by both tetanic and theta-burst stimulation in both apical and basal dendrites of CA1 pyramidal neurones but does not affect long-term depression. This selective effect on long-term potentiation does not appear to be mediated through inhibition of N-methyl-D-aspartate or metabotropic glutamate receptor function, but likely resides downstream of receptor activation, possibly at the level of the kinase cascade that converts short-term into long-term potentiation. Our results indicate possible mechanisms by which the neuropeptide galanin may act at the molecular level to influence learning and memory in vertebrates.