Summary: NMDA Receptor-Mediated Control of Presynaptic Calcium and
Amanda J. Cochilla and Simon Alford
Department of Physiology and Northwestern University Institute for Neuroscience, Northwestern University Medical
School, Chicago, Illinois 60611
Before action potential-evoked Ca2
transients, basal presyn-
concentration may profoundly affect the amplitude
of subsequent neurotransmitter release. Reticulospinal axons
of the lamprey spinal cord receive glutamatergic synaptic input.
We have investigated the effect of this input on presynaptic
concentrations and evoked release of neurotransmitter.
Paired recordings were made between reticulospinal axons and
the neurons that make axo-axonic synapses onto those axons.
Both excitatory and inhibitory paired-cell responses were re-
corded in the axons. Excitatory synaptic inputs were blocked
by the AMPA receptor antagonist 6-cyano-7-nitroquinoxaline-
2,3-dione (CNQX; 10 M) and by the NMDA receptor antagonist