A presynaptic locus of the action of Met-enkephalin demonstrated in mouse spinal cord cultures.
Monosynaptic excitatory post-synaptic potentials (EPSPs) evoked in spinal cord (SC) neurons by stimulation of dorsal root ganglion (DRG) neurons in cell cultures were reduced by perfusion application of the opiate peptide, Met-enkephalin (2-4 microM). In about 2/3 of cases examined, EPSPs evoked by stimulation of spinal cord cells were also reduced by Met-enkephalin. The effects were antagonized by concomitant perfusion with naloxone (1-2 microM) and recovered when perfusion with Met-enkephalin was stopped. Statistical analysis of synaptic responses indicated that the reduction of EPSP amplitude was due, at least to a major extent, to a decrease in presynaptic transmitter release.
Jia
M
M
Laboratory of Developmental Neurobiology, National Institute of Child Health and Human Development, Bethesda, MD 20892.
Nelson
P G
PG
D000818:Animals; D002478:Cells, Cultured; D004594:Electrophysiology; D004744:Enkephalin, Methionine / Q000494:pharmacology*; D005260:Female; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D009270:Naloxone / Q000494:pharmacology; D011247:Pregnancy; D013116:Spinal Cord / Q000187:drug effects*; D013569:Synapses / Q000187:drug effects
D009270:Naloxone; D004744:Enkephalin, Methionine