[Memory, learning and glutamate receptor].

After a brief tetanic stimulation of an excitatory pathway in the hippocampus, synaptic transmission through the tetanized pathway is facilitated for a long period. This phenomenon is called long-term potentiation (LTP), and has been regarded as a neuronal correlate with learning and memory. Features of LPT in Schaffer collateral-CA1 neuron are calcium-dependency, input-specificity, cooperativity and sensitivity to blockers of N-methyl-D-aspartate (NMDA) receptors. These features can be explained by properties of NMDA receptors. LTP in mossy fiber-CA3 neuron has features different from those in field CA1: It is insensitive to blockers of NMDA receptors and does not show cooperativity. Quantal analysis of transmission through mossy fiber synapses before and after generation of LTP reveals that LTP resulted from facilitated release of transmitter. Participation of the metabotropic glutamate receptor is suggested.