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Selective Requirement for Maintenance of Synaptic Contacts onto Motoneurons by Target-Derived trkB Receptors.

Zhu X, Ward PJ, English AW - Neural Plast. (2016)

Bottom Line: Selective knockout of the trkB gene resulted in a marked reduction in contacts made by VGLUT2- and GAD67-immunoreactive structures in both sexes and a significant reduction in contacts containing only glycine in male mice.No reduction was found for glycinergic contacts in female mice or for VGLUT1 immunoreactive contacts in either sex.Signaling through postsynaptic trkB receptors is considered to be an essential part of a cellular mechanism for maintaining the contacts of some, but not all, synaptic contacts onto motoneurons.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA.

ABSTRACT
Synaptic contacts onto motoneurons were studied in mice in which the gene for the trkB neurotrophin receptor was knocked out selectively in a subset of spinal motoneurons. The extent of contacts by structures immunoreactive for either of two different vesicular glutamate transporters (VGLUT1 and VGLUT2), the vesicular GABA transporter, or glutamic acid decarboxylase 67 (GAD67) with the somata of motoneurons, was studied in wild type and trkB knockout cells in tamoxifen treated male and female SLICK-trkB(-/-) mice. Selective knockout of the trkB gene resulted in a marked reduction in contacts made by VGLUT2- and GAD67-immunoreactive structures in both sexes and a significant reduction in contacts containing only glycine in male mice. No reduction was found for glycinergic contacts in female mice or for VGLUT1 immunoreactive contacts in either sex. Signaling through postsynaptic trkB receptors is considered to be an essential part of a cellular mechanism for maintaining the contacts of some, but not all, synaptic contacts onto motoneurons.

No MeSH data available.


Related in: MedlinePlus

(a) The mean percent coverage (±SEM) by contacts immunoreactive to VGLUT1, VGLUT2, GAD67, or glycine in male and female tamoxifen treated SLICK::trkBf/f mice. These values were determined for each synapse-associated protein by averaging data from individual mice in the different groups. The significance of differences between groups was then evaluated with ANOVA. The estimated percent coverage by contacts containing glycine equals the percent coverage by VGAT+ contacts minus percent coverage by GAD67. WT refers to wildtype motoneurons without YFP that still retain trkB receptors. KO refers to knockout motoneurons labeled with YFP that do not have trkB receptors. †p < 0.05 versus WT and ∗p < 0.05 versus female. (b) The same data are expressed as mean (±95% confidence limits) percent differences between WT cells and KO cells.
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fig4: (a) The mean percent coverage (±SEM) by contacts immunoreactive to VGLUT1, VGLUT2, GAD67, or glycine in male and female tamoxifen treated SLICK::trkBf/f mice. These values were determined for each synapse-associated protein by averaging data from individual mice in the different groups. The significance of differences between groups was then evaluated with ANOVA. The estimated percent coverage by contacts containing glycine equals the percent coverage by VGAT+ contacts minus percent coverage by GAD67. WT refers to wildtype motoneurons without YFP that still retain trkB receptors. KO refers to knockout motoneurons labeled with YFP that do not have trkB receptors. †p < 0.05 versus WT and ∗p < 0.05 versus female. (b) The same data are expressed as mean (±95% confidence limits) percent differences between WT cells and KO cells.

Mentions: In addition, we evaluated the significance of differences in mean synaptic coverage between groups using ANOVA. Mean (±SEM) percent synaptic coverages from WT and KO cells in treated and control animals are shown in Figure 4(a). The same data are expressed as percent change in synaptic coverage in Figure 4(b). No significant difference in percent VGLUT1 coverage was found between WT male, WT female, KO male, KO female, and controls (F4,15 = 1.76, n.s.).


Selective Requirement for Maintenance of Synaptic Contacts onto Motoneurons by Target-Derived trkB Receptors.

Zhu X, Ward PJ, English AW - Neural Plast. (2016)

(a) The mean percent coverage (±SEM) by contacts immunoreactive to VGLUT1, VGLUT2, GAD67, or glycine in male and female tamoxifen treated SLICK::trkBf/f mice. These values were determined for each synapse-associated protein by averaging data from individual mice in the different groups. The significance of differences between groups was then evaluated with ANOVA. The estimated percent coverage by contacts containing glycine equals the percent coverage by VGAT+ contacts minus percent coverage by GAD67. WT refers to wildtype motoneurons without YFP that still retain trkB receptors. KO refers to knockout motoneurons labeled with YFP that do not have trkB receptors. †p < 0.05 versus WT and ∗p < 0.05 versus female. (b) The same data are expressed as mean (±95% confidence limits) percent differences between WT cells and KO cells.
© Copyright Policy - open-access
Related In: Results  -  Collection

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fig4: (a) The mean percent coverage (±SEM) by contacts immunoreactive to VGLUT1, VGLUT2, GAD67, or glycine in male and female tamoxifen treated SLICK::trkBf/f mice. These values were determined for each synapse-associated protein by averaging data from individual mice in the different groups. The significance of differences between groups was then evaluated with ANOVA. The estimated percent coverage by contacts containing glycine equals the percent coverage by VGAT+ contacts minus percent coverage by GAD67. WT refers to wildtype motoneurons without YFP that still retain trkB receptors. KO refers to knockout motoneurons labeled with YFP that do not have trkB receptors. †p < 0.05 versus WT and ∗p < 0.05 versus female. (b) The same data are expressed as mean (±95% confidence limits) percent differences between WT cells and KO cells.
Mentions: In addition, we evaluated the significance of differences in mean synaptic coverage between groups using ANOVA. Mean (±SEM) percent synaptic coverages from WT and KO cells in treated and control animals are shown in Figure 4(a). The same data are expressed as percent change in synaptic coverage in Figure 4(b). No significant difference in percent VGLUT1 coverage was found between WT male, WT female, KO male, KO female, and controls (F4,15 = 1.76, n.s.).

Bottom Line: Selective knockout of the trkB gene resulted in a marked reduction in contacts made by VGLUT2- and GAD67-immunoreactive structures in both sexes and a significant reduction in contacts containing only glycine in male mice.No reduction was found for glycinergic contacts in female mice or for VGLUT1 immunoreactive contacts in either sex.Signaling through postsynaptic trkB receptors is considered to be an essential part of a cellular mechanism for maintaining the contacts of some, but not all, synaptic contacts onto motoneurons.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell Biology, Emory University School of Medicine, Atlanta, GA 30322, USA.

ABSTRACT
Synaptic contacts onto motoneurons were studied in mice in which the gene for the trkB neurotrophin receptor was knocked out selectively in a subset of spinal motoneurons. The extent of contacts by structures immunoreactive for either of two different vesicular glutamate transporters (VGLUT1 and VGLUT2), the vesicular GABA transporter, or glutamic acid decarboxylase 67 (GAD67) with the somata of motoneurons, was studied in wild type and trkB knockout cells in tamoxifen treated male and female SLICK-trkB(-/-) mice. Selective knockout of the trkB gene resulted in a marked reduction in contacts made by VGLUT2- and GAD67-immunoreactive structures in both sexes and a significant reduction in contacts containing only glycine in male mice. No reduction was found for glycinergic contacts in female mice or for VGLUT1 immunoreactive contacts in either sex. Signaling through postsynaptic trkB receptors is considered to be an essential part of a cellular mechanism for maintaining the contacts of some, but not all, synaptic contacts onto motoneurons.

No MeSH data available.


Related in: MedlinePlus