Abstract
The entorhinal cortex provides both direct and indirect inputs to hippocampal CA1 neurons through the perforant path and Schaffer collateral synapses, respectively. Using both two-photon imaging of synaptic vesicle cycling and electrophysiological recordings, we found that the efficacy of transmitter release at perforant path synapses is lower than at Schaffer collateral inputs. This difference is due to the greater contribution to release by presynaptic N-type voltage-gated Ca(2+) channels at the Schaffer collateral than perforant path synapses. Induction of long-term potentiation that depends on activation of NMDA receptors and L-type voltage-gated Ca(2+) channels enhances the low efficacy of release at perforant path synapses by increasing the contribution of N-type channels to exocytosis. This represents a previously uncharacterized presynaptic mechanism for fine-tuning release properties of distinct classes of synapses onto a common postsynaptic neuron and for regulating synaptic function during long-term synaptic plasticity.
Publication types
-
Research Support, N.I.H., Extramural
-
Research Support, Non-U.S. Gov't
MeSH terms
-
2-Amino-5-phosphonovalerate / pharmacology
-
6-Cyano-7-nitroquinoxaline-2,3-dione / pharmacology
-
Analysis of Variance
-
Animals
-
Biophysics
-
Calcium Channel Blockers / pharmacology
-
Calcium Channels, N-Type / physiology*
-
Dose-Response Relationship, Drug
-
Electric Stimulation / methods
-
Excitatory Amino Acid Antagonists / pharmacology
-
Excitatory Postsynaptic Potentials / drug effects
-
Excitatory Postsynaptic Potentials / physiology
-
Hippocampus / cytology*
-
In Vitro Techniques
-
Kinetics
-
Long-Term Potentiation / drug effects
-
Long-Term Potentiation / physiology*
-
Mice
-
Mice, Inbred C57BL
-
Patch-Clamp Techniques / methods
-
Perforant Pathway / cytology*
-
Photons
-
Pyridinium Compounds / metabolism
-
Quaternary Ammonium Compounds / metabolism
-
Recruitment, Neurophysiological / physiology*
-
Synapses / drug effects
-
Synapses / physiology*
-
Time Factors
-
omega-Agatoxin IVA / pharmacology
Substances
-
Calcium Channel Blockers
-
Calcium Channels, N-Type
-
Excitatory Amino Acid Antagonists
-
FM1 43
-
Pyridinium Compounds
-
Quaternary Ammonium Compounds
-
omega-Agatoxin IVA
-
6-Cyano-7-nitroquinoxaline-2,3-dione
-
2-Amino-5-phosphonovalerate