Control of postsynaptic Ca2+ influx in developing neocortex by excitatory and inhibitory neurotransmitters

Neuron. 1991 Mar;6(3):333-44. doi: 10.1016/0896-6273(91)90243-s.


We assessed the pathways by which excitatory and inhibitory neurotransmitters elicit postsynaptic changes in [Ca2+]i in brain slices of developing rat and cat neocortex, using fura 2. Glutamate, NMDA, and quisqualate transiently elevated [Ca2%]i in all neurons. While the quisqualate response relied exclusively on voltage-gated Ca2+ channels, almost all of the NMDA-induced Ca2+ influx was via the NMDA ionophore itself, rather than through voltage-gated Ca2+ channels. Glutamate itself altered [Ca2+]i almost exclusively via the NMDA receptor. Furthermore, synaptically induced Ca2+ entry relied almost completely on NMDA receptor activation, even with low-frequency stimulation. The inhibitory neurotransmitter GABA also increased [Ca2+]i, probably via voltage-sensitive Ca2+ channels, whereas the neuromodulator acetylcholine caused Ca2+ release from intracellular stores via a muscarinic receptor. Low concentrations of these agonists produced nonperiodic [Ca2+]i oscillations, which were temporally correlated in neighbouring cells. Optical recording with Ca2(+)-sensitive indicators may thus permit the visualization of functional networks in developing cortical circuits.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylcholine / pharmacology
  • Animals
  • Biological Transport, Active / drug effects
  • Biological Transport, Active / physiology
  • Calcium / metabolism*
  • Calcium Channels / drug effects
  • Calcium Channels / physiology
  • Carbachol / pharmacology
  • Cats
  • Cerebral Cortex / drug effects
  • Cerebral Cortex / metabolism*
  • Cerebral Cortex / physiology
  • Glutamates / pharmacology
  • Glutamic Acid
  • N-Methylaspartate / pharmacology
  • Neurons / drug effects
  • Neurons / physiology
  • Neurotransmitter Agents / pharmacology*
  • Quisqualic Acid / pharmacology
  • Rats
  • Receptors, N-Methyl-D-Aspartate / drug effects
  • Receptors, N-Methyl-D-Aspartate / physiology
  • gamma-Aminobutyric Acid / pharmacology


  • Calcium Channels
  • Glutamates
  • Neurotransmitter Agents
  • Receptors, N-Methyl-D-Aspartate
  • Glutamic Acid
  • gamma-Aminobutyric Acid
  • N-Methylaspartate
  • Quisqualic Acid
  • Carbachol
  • Acetylcholine
  • Calcium