Calcium agonist (BayK 8644) augments voltage-sensitive calcium currents but not synaptic transmission in cultured mouse spinal cord neurons.
The effects of the calcium agonist, BayK 8644, and other agents upon voltage-dependent calcium conductance (VSCC) and evoked synaptic activity were studied in cultured mouse spinal cord and dorsal root ganglion neurons. As expected, BayK 8644 increased the VSCC corresponding to L channels. It had relatively little effect on evoked synaptic activity; the small but statistically significant effect that was noted was a decrease. Nitrendipine had either no effect or an increase with no statistically significant effect being seen with regard to synaptic activity over the population sampled. An increased extracellular Ca++ concentration increased both VSCC and synaptic activity. We conclude that VSCC with L channel properties are probably not involved in transmitter release produced by action potentials in the central synapses occurring in the dissociated mouse spinal cord cell culture system.
Yu
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Laboratory of Developmental Neurobiology, National Institute of Child Health and Human Development, Bethesda, MD 20892.
Jia
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M
Litzinger
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Nelson
P G
PG
D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / Q000494:pharmacology*; D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D002118:Calcium / Q000502:physiology*; D002478:Cells, Cultured; D004558:Electric Stimulation; D005727:Ganglia, Spinal / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D009568:Nitrendipine / Q000494:pharmacology; D009435:Synaptic Transmission / Q000187:drug effects*; D013757:Tetraethylammonium Compounds / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology
D013757:Tetraethylammonium Compounds; D013779:Tetrodotoxin; D001498:3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester; D009568:Nitrendipine; D002118:Calcium