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Development of GABAergic connections in vitro: increasing efficacy of synaptic transmission is not accompanied by changes in miniature currents.
J Neurobiol 1992; 23(6):766-81JN

Abstract

Development of inhibitory synaptic transmission was studied using a dissociated cell culture from the superior colliculus of neonatal rat. Patch-clamp recordings in the whole-cell configuration were performed to measure evoked (single-cell-activated) inhibitory postsynaptic currents (IPSCs), miniature IPSCs and current responses to maximal concentrations of exogenous gamma-aminobutyric acid (GABA). Over a period of 3 weeks in vitro (DIV3-24), the fraction of synaptically coupled neurons raised from 0% to 76%. Evoked IPSCs were first observed at DIV5. They had an average amplitude of 33.9 pA during the first week (n = 13) and 129.7 pA during the fourth week (n = 48). This increase by a factor of 3.8 represents a significant rise in the efficacy of GABAergic transmission during in vitro development. However, no developmental change has been observed in the average amplitudes of miniature somatic IPSCs. The latter remained at an average level of about 9 pA (symmetrical chloride concentration and a driving force of 68 mV). No increase was found also in whole-cell current densities induced by saturating concentrations of exogenous GABA. Our results suggest that under the given conditions, synapse maturation was primarily the result of presynaptic sprouting. This conclusion is further supported by bouton counts in immunostained collicular cultures, where the number of axosomatic and axodendritic GABAergic contacts per neuron increased from 0.54 and 0.37, respectively, at DIV3, to 13.84 and greater than 23.1, at DIV24. The overall density of GABAergic neurons decreased during this period from about 41,000/cm2 to 15,600 cm2, indicating that a growing number of contacts is formed by a declining number of presynaptic neurons.

Authors+Show Affiliations

Department of Neurophysiology, Max-Planck-Institute for Psychiatry, Martinsried, Germany.No affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

1331318

Citation

Kraszewski, K, and R Grantyn. "Development of GABAergic Connections in Vitro: Increasing Efficacy of Synaptic Transmission Is Not Accompanied By Changes in Miniature Currents." Journal of Neurobiology, vol. 23, no. 6, 1992, pp. 766-81.
Kraszewski K, Grantyn R. Development of GABAergic connections in vitro: increasing efficacy of synaptic transmission is not accompanied by changes in miniature currents. J Neurobiol. 1992;23(6):766-81.
Kraszewski, K., & Grantyn, R. (1992). Development of GABAergic connections in vitro: increasing efficacy of synaptic transmission is not accompanied by changes in miniature currents. Journal of Neurobiology, 23(6), pp. 766-81.
Kraszewski K, Grantyn R. Development of GABAergic Connections in Vitro: Increasing Efficacy of Synaptic Transmission Is Not Accompanied By Changes in Miniature Currents. J Neurobiol. 1992;23(6):766-81. PubMed PMID: 1331318.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Development of GABAergic connections in vitro: increasing efficacy of synaptic transmission is not accompanied by changes in miniature currents. AU - Kraszewski,K, AU - Grantyn,R, PY - 1992/8/1/pubmed PY - 1992/8/1/medline PY - 1992/8/1/entrez SP - 766 EP - 81 JF - Journal of neurobiology JO - J. Neurobiol. VL - 23 IS - 6 N2 - Development of inhibitory synaptic transmission was studied using a dissociated cell culture from the superior colliculus of neonatal rat. Patch-clamp recordings in the whole-cell configuration were performed to measure evoked (single-cell-activated) inhibitory postsynaptic currents (IPSCs), miniature IPSCs and current responses to maximal concentrations of exogenous gamma-aminobutyric acid (GABA). Over a period of 3 weeks in vitro (DIV3-24), the fraction of synaptically coupled neurons raised from 0% to 76%. Evoked IPSCs were first observed at DIV5. They had an average amplitude of 33.9 pA during the first week (n = 13) and 129.7 pA during the fourth week (n = 48). This increase by a factor of 3.8 represents a significant rise in the efficacy of GABAergic transmission during in vitro development. However, no developmental change has been observed in the average amplitudes of miniature somatic IPSCs. The latter remained at an average level of about 9 pA (symmetrical chloride concentration and a driving force of 68 mV). No increase was found also in whole-cell current densities induced by saturating concentrations of exogenous GABA. Our results suggest that under the given conditions, synapse maturation was primarily the result of presynaptic sprouting. This conclusion is further supported by bouton counts in immunostained collicular cultures, where the number of axosomatic and axodendritic GABAergic contacts per neuron increased from 0.54 and 0.37, respectively, at DIV3, to 13.84 and greater than 23.1, at DIV24. The overall density of GABAergic neurons decreased during this period from about 41,000/cm2 to 15,600 cm2, indicating that a growing number of contacts is formed by a declining number of presynaptic neurons. SN - 0022-3034 UR - https://www.unboundmedicine.com/medline/citation/1331318/Development_of_GABAergic_connections_in_vitro:_increasing_efficacy_of_synaptic_transmission_is_not_accompanied_by_changes_in_miniature_currents_ L2 - https://doi.org/10.1002/neu.480230613 DB - PRIME DP - Unbound Medicine ER -