Reconstitution of the hippocampal mossy fiber and associational-commissural pathways in a novel dissociated cell culture system.
Synapses of the hippocampal mossy fiber pathway exhibit several characteristic features, including a unique form of long-term potentiation that does not require activation of the N-methyl-D-aspartate receptor by glutamate, a complex postsynaptic architecture, and sprouting in response to seizures. However, these connections have proven difficult to study in hippocampal slices because of their relative paucity (<0.4%) compared to commissural-collateral synapses. To overcome this problem, we have developed a novel dissociated cell culture system in which we have enriched mossy fiber synapses by increasing the ratio of granule-to-pyramidal cells. As in vivo, mossy fiber connections are composed of large dynorphin A-positive varicosities contacting complex spines (but without a restricted localization). The elementary synaptic connections are glutamatergic, inhibited by dynorphin A, and exhibit N-methyl-D-aspartate-independent long-term potentiation. Thus, the simplicity and experimental accessibility of this enriched in vitro mossy fiber pathway provides a new perspective for studying nonassociative plasticity in the mammalian central nervous system.
Baranes
D
D
Howard Hughes Medical Institute, College of Physicians and Surgeons of Columbia University, NY 10032, USA.
López-García
J C
JC
Chen
M
M
Bailey
C H
CH
Kandel
E R
ER
D000818:Animals; D002469:Cell Separation; D002478:Cells, Cultured; D004399:Dynorphins / Q000494:pharmacology / Q000502:physiology; D004594:Electrophysiology; D006624:Hippocampus / Q000166:cytology* / Q000187:drug effects / Q000502:physiology*; D017774:Long-Term Potentiation / Q000187:drug effects / Q000502:physiology; D008854:Microscopy, Electron; D016202:N-Methylaspartate / Q000502:physiology; D017966:Pyramidal Cells / Q000502:physiology; D051381:Rats; D013569:Synapses / Q000502:physiology
D016202:N-Methylaspartate; D004399:Dynorphins