Dendritic action potentials activated by NMDA receptor-mediated EPSPs in CA1 hippocampal pyramidal cells

Intradendritic recordings were obtained in rat CA1 hippocampal pyramidal cells. Repetitive stimulation produced substantial short-term potentiation of the dendritic excitatory postsynaptic potential (EPSP) which was partly attributable to activation of n-methyl-D-aspartate receptors. Accompanying the potentiated synaptic response were Na(+)-mediated spikes which appeared to originate at multiple sites in the dendritic arbor. These discrete dendritic action potentials are rarely distinguishable in somatic recordings, but may contribute to the subthreshold response at the pyramidal cell body. In addition, dendritic spikes may interact with other voltage-dependent dendritic conductances.