NMDA and non-NMDA receptors are co-localized at excitatory synapses of rat hypoglossal motoneurons.
We used whole-cell patch clamp recordings in a rat brainstem slice preparation to characterize the properties of miniature excitatory postsynaptic currents (mEPSCs) in hypoglossal motoneurons. The distinct kinetic characteristics of N-methyl-D-aspartate (NMDA) and non-NMDA receptor-mediated synaptic responses allowed us to study dual component mEPSCs mediated by the two receptor types. Using this approach, NMDA and non-NMDA receptors were found to be co-localized at the same synaptic locations. In addition, some sites contain only NMDA receptors since a large proportion of mEPSCs were apparently mediated by NMDA receptors only. Furthermore, the amplitudes of pharmacologically isolated NMDA receptor-mediated mEPSCs were highly variable in individual cells and their decay kinetics were modulated by membrane potential.
O'Brien
J A
JA
Department of Physiology and Biophysics, University of Washington School of Medicine, Seattle 98195-7290, USA. jaobrien@u.washington.edu
Isaacson
J S
JS
Berger
A J
AJ
D000818:Animals; D000831:Animals, Newborn; D001640:Bicuculline / Q000031:analogs & derivatives / Q000494:pharmacology; D005071:Evoked Potentials / Q000187:drug effects / Q000502:physiology; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D007002:Hypoglossal Nerve / Q000737:chemistry* / Q000166:cytology; D066298:In Vitro Techniques; D009046:Motor Neurons / Q000737:chemistry*; D018408:Patch-Clamp Techniques; D051381:Rats; D017207:Rats, Sprague-Dawley; D017470:Receptors, Glutamate / Q000032:analysis*; D016194:Receptors, N-Methyl-D-Aspartate / Q000032:analysis*; D013331:Strychnine / Q000494:pharmacology; D013569:Synapses / Q000737:chemistry*; D013779:Tetrodotoxin / Q000494:pharmacology
D018691:Excitatory Amino Acid Antagonists; D017470:Receptors, Glutamate; D016194:Receptors, N-Methyl-D-Aspartate; C017069:bicuculline methiodide; D013779:Tetrodotoxin; D013331:Strychnine; D001640:Bicuculline