Amplification of perforant-path EPSPs in CA3 pyramidal cells by LVA calcium and sodium channels.
The perforant path forms a monosynaptic connection between the cells of layer II of the entorhinal cortex and the pyramidal cells in hippocampal area CA3. Although this projection is prominent anatomically, very little is known about the physiological properties of this input. The distal location of these synapses suggests that somatically recorded perforant-path excitatory postsynaptic potentials (EPSPs) may be influenced by the activation of voltage-dependent channels in CA3 cells. We observed that perforant-path EPSPs are reduced (by approximately 25%) by blockade of postsynaptic low-voltage-activated calcium and sodium channels, indicating that perforant-path EPSPs are amplified by the activation of these channels. These data suggest that the perforant path may represent an important and highly modifiable direct connection between the entorhinal cortex and area CA3.
Urban
N N
NN
Department of Neuroscience, University of Pittsburgh, Pennsylvania 15260, USA.
Henze
D A
DA
Barrionuevo
G
G
D000818:Animals; D000927:Anticonvulsants / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000502:physiology*; D004558:Electric Stimulation; D005013:Ethosuximide / Q000494:pharmacology; D018690:Excitatory Amino Acid Agonists / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects / Q000502:physiology*; D006624:Hippocampus / Q000166:cytology / Q000502:physiology; D015640:Ion Channel Gating / Q000502:physiology; D008297:Male; D009434:Neural Pathways; D009532:Nickel / Q000494:pharmacology; D009543:Nifedipine / Q000494:pharmacology; D019580:Perforant Pathway / Q000166:cytology / Q000502:physiology*; D017966:Pyramidal Cells / Q000737:chemistry / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015222:Sodium Channels / Q000502:physiology*; D013779:Tetrodotoxin / Q000494:pharmacology; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000494:pharmacology
D000927:Anticonvulsants; D002121:Calcium Channel Blockers; D015220:Calcium Channels; D018690:Excitatory Amino Acid Agonists; D015222:Sodium Channels; D013779:Tetrodotoxin; D005013:Ethosuximide; C022838:nickel chloride; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; D009532:Nickel; D009543:Nifedipine