Long-Term Potentiation of Hippocampal Mossy Fiber Synapses is Blocked by Postsynaptic Injection of Calcium Chelators.

摘要

The role of intracellular calcium in an amino-phosphonovalerate-insensitive form of long-term potentiation (LTP) has been studied at the hippocampal mossy fiber synapse. Intracellular calcium was buffered by iontophoretic injection of either BAPTA or QUIN-2 into CA3 pyramidal neurons. The slow calcium-dependent after hyperpolarization was used as an indicator of buffering. Long-term potentiation was elicited in control and in amino-phosphonovalerate-treated cells (6/6 and 4/5 cell, respectively). In contrast, long-term potentiation was observed in only 2/9 BAPTA-loaded cells and in 1/4 QUIN-2-loaded cells. The magnitude of LTP for control and APV-treated cells was not significantly different, but both groups showed significantly greater long-term potentiation than BAPTA-loaded cells. These results suggest that an increase in postsynaptic calcium is required for the induction of mossy fiber Long-term potentiation. Hippocampus, LTP, Mossy fiber synapses, Calcium, CA3, Reprints, Neurochemistry, Chelate compounds. (jg)