Dantrolene inhibits long-term depression and depotentiation of synaptic transmission in the rat dentate gyrus.

The involvement of Ca release from intracellular stores in the induction of long-term depression and depotentiation of excitatory synaptic transmission was investigated in the rat dentate gyrus using dantrolene, an agent known to block Ca release via the ryanodine receptor. In control slices, low-frequency stimulation (1 Hz for 15 min) induced robust long-term depression of baseline field excitatory postsynaptic potentials and depotentiation of previously established long-term potentiation. Dantrolene (50 microM) was found to block completely both long-term depression of baseline responses and depotentiation. Moreover, long-term potentiation induced by high-frequency stimulation was enhanced in the presence of dantrolene.