Formation and maturation of synapses in primary cultures of rat cerebral cortical cells: an electron microscopic study

doi:10.1016/0168-0102(93)90076-3

Neuroscience Research

Volume 16, Issue 2, February 1993, Pages 95-103

https://doi.org/10.1016/0168-0102(93)90076-3 Get rights and content

Abstract

Cerebral cortical cells from fetal rats (18 days) were cultured for 3, 7, 14, 21, 28, 35 days in vitro (DIV) and the development of synapses was examined morphologically by electron microscopy. At 3 DIV, no synapses could be recognized. An immature type of synapse was found at 7 DIV which thereafter developed morphologically. The length of the synaptic contact zone (SCZ) increased with DIV from 271 ± 11.4 nm (mean ± SEM) at 7 DIV to 410 ± 11.4 nm at 35 DIV. The number of synaptic vesicles per terminal also increased with DIV: 10.0 ± 1.2 at 7 DIV, 35.7 ± 3.4 at 21 DIV, and 53.3 ± 4.5 at 35 DIV. The time course of numerical density of synapses was examined quantitatively by electron microscopy. Synaptic density was very low at 7 DIV. It was significantly increased at 14 DIV and thereafter showed variable changes. Four culture series showed decreases after 14 DIV, but one series showed a further increase at 21 DIV followed by a decrease at 28 DIV. The mean density of synapses at each DIV was as follows: $1780 ± 8610^{6} μ m^{3}$ at 7 DIV, $4244 ± 59510^{6} μ m^{3}$ at 14 DIV, $2285 ± 67410^{6} μ m^{3}$ at 21 DIV, $2552 ± 64610^{6} μ m^{3}$ at 28 DIV, and $2080 ± 53210^{6} μ m^{3}$ at 35 DIV. Neuronal cell density was counted in each culture to calculate the relative number of synapses per neuron. The cell density decreased with age from $301 ± 5110^{6} μ m^{3}$ at 7 DIV to $39 ± 910^{6} μ m^{3}$ at 35 DIV. The number of synapse per neuron increased with DIV to the end of the 4th week (from 64.1 ± 9.8 at 7 DIV to 1130.1 ± 254.3 at 28 DIV). The time course of synapse formation in culture resembled that in the cerebral cortex in vivo.

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Research reportFormation and maturation of synapses in primary cultures of rat cerebral cortical cells: an electron microscopic study

Abstract

Brain Res.

J. Neurosci. Methods

J. Neurosci. Methods.

Brain Res.

Brain Res.

Dev. Brain Res.

Dev. Brain Res.

Neurosci. Res.

Exp. Neurol.

Neurochem. Int.

Neurosci. Lett.

Dev. Brain Res.

Dev. Brain Res.

Dev. Brain Res.

Research report
Formation and maturation of synapses in primary cultures of rat cerebral cortical cells: an electron microscopic study