PMID- 3020146
OWN - NLM
STAT- MEDLINE
DCOM- 19861120
LR  - 20220216
IS  - 0022-0949 (Print)
IS  - 0022-0949 (Linking)
VI  - 124
DP  - 1986 Sep
TI  - Amino acid receptor-mediated transmission at primary afferent synapses in rat 
      spinal cord.
PG  - 239-58
AB  - Intracellular recording techniques have been used to provide information on the 
      identity of excitatory transmitters released at synapses formed between dorsal 
      root ganglion (DRG) and spinal cord neurones in two in vitro preparations. 
      Explants of embryonic rat DRG were added to dissociated cultures of embryonic 
      dorsal horn neurones and synaptic potentials recorded intracellularly from dorsal 
      horn neurones after DRG explant stimulation. More than 80% of dorsal horn 
      neurones received at least one fast, DRG-evoked, monosynaptic input. In the 
      presence of high divalent cation concentrations (5 mmol l-1 Ca2+, 3 mmol l-1 
      Mg2+) the acidic amino acid receptor agonists, L-glutamate, kainate (KA) and 
      quisqualate (QUIS) excited all dorsal horn neurones which received a monosynaptic 
      DRG neurone input, whereas L-aspartate and N-methyl-D-aspartate (NMDA) had little 
      or no action. 2-Amino-5-phosphonovalerate (APV), a selective NMDA receptor 
      antagonist, was relatively ineffective at antagonizing DRG-evoked synaptic 
      potentials and L-glutamate-evoked responses. In contrast, kynurenate was found to 
      be a potent antagonist of amino acid-evoked responses and of synaptic 
      transmission at all DRG-dorsal horn synapses examined. The blockade of synaptic 
      transmission by kynurenate appeared to result from a postsynaptic action on 
      dorsal horn neurones. Intracellular recordings from motoneurones in new-born rat 
      spinal cord were used to study the sensitivity of the Ia excitatory postsynaptic 
      potential (EPSP) to antagonists of excitatory amino acids. Superfusion of the 
      spinal cord with APV did not inhibit the Ia EPSP but did suppress later, 
      polysynaptic components of the afferent-evoked response. Kynurenate was a potent 
      and selective inhibitor of the Ia EPSP, acting via a postsynaptic mechanism. 
      These findings indicate that L-glutamate, or a glutamate-like compound, but not 
      L-aspartate, is likely to be the predominant excitatory transmitter that mediates 
      fast excitatory postsynaptic potentials at primary afferent synapses with both 
      dorsal horn neurones and motoneurones.
FAU - Jessell, T M
AU  - Jessell TM
FAU - Yoshioka, K
AU  - Yoshioka K
FAU - Jahr, C E
AU  - Jahr CE
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - England
TA  - J Exp Biol
JT  - The Journal of experimental biology
JID - 0243705
RN  - 0 (Amino Acids)
RN  - 0 (Amino Acids, Dicarboxylic)
RN  - 0 (Receptors, Amino Acid)
RN  - 0 (Receptors, Cell Surface)
SB  - IM
MH  - Afferent Pathways/*physiology
MH  - Amino Acids/metabolism
MH  - Amino Acids, Dicarboxylic/pharmacology
MH  - Animals
MH  - Cells, Cultured
MH  - Ganglia, Spinal/*physiology
MH  - In Vitro Techniques
MH  - Membrane Potentials/drug effects
MH  - Motor Neurons/physiology
MH  - Rats
MH  - Receptors, Amino Acid
MH  - Receptors, Cell Surface/*physiology
MH  - Spinal Cord/*physiology
MH  - Synapses/*physiology
MH  - *Synaptic Transmission
EDAT- 1986/09/01 00:00
MHDA- 1986/09/01 00:01
CRDT- 1986/09/01 00:00
PHST- 1986/09/01 00:00 [pubmed]
PHST- 1986/09/01 00:01 [medline]
PHST- 1986/09/01 00:00 [entrez]
AID - 10.1242/jeb.124.1.239 [doi]
PST - ppublish
SO  - J Exp Biol. 1986 Sep;124:239-58. doi: 10.1242/jeb.124.1.239.