Journal: Frontiers in Synaptic Neuroscience

Article Title: GABA B receptors negatively modulate excitatory plasticity at the mossy fiber synapse onto parvalbumin-expressing basket and axo-axonic cells in the dentate gyrus

doi: 10.3389/fnsyn.2025.1656759

Figure Lengend Snippet: GABA B Rs and Kir3 channels are expressed on the basal dendrites of PV-INs. (A) Consecutive electron micrographs show the localization of immunogold particles for the GABA B1 subunit to extrasynaptic (arrows) and perisynaptic positions (double arrows) over the membrane surface of PV+ dendrites (Den 1 , peroxidase reaction end-product) in the DG hilus. Axon terminals (b 1 –b 3 ) of putative excitatory cells contact Den 1 . Note the immunoreactivity for the receptor subunit was also detected in a neighbouring dendritic shaft (Den 2 ) and spines (s 1 –s 2 ) of peroxidase-negative neurons. (B) Consecutive electron micrographs illustrate immunoreactivity for the Kir3.1 subunit (immunogold particles) in extrasynaptic (arrows) and perisynaptic positions (double arrow) on the membrane of a PV+ dendrite shaft (Den, peroxidase reaction end-product) contacted by axon terminals (b 1 –b 3 ) of putative excitatory cells. (C) Summary plot of the surface density of GABA B1 particles on PV+ dendrites (7.9 ± 0.9 particles/μm 2 ). PV-IN data collected from two animals color-coded as animal 1 (gray dots) and animal 2 (red dots). (D) Summary plot of the surface density of Kir3.1 particles on PV+ dendrites (6.1 ± 0.8 particles/μm 2 ). PV-IN data collected from two animals color-coded as animal 1 (gray dots) and animal 2 (red dots). Number of analyzed dendrites are in parentheses. Scale bars, 200 nm. All violin plots show median as solid line and upper and lower quartiles as dotted lines.

Article Snippet: To test the involvement of Kir3 channels, we preapplied the Kir3 channel blocker SCH-23390 (SCH; 10 μM; TOCRIS) to the aCSF.

Techniques: Membrane

Journal: Frontiers in Synaptic Neuroscience

Article Title: GABA B receptors negatively modulate excitatory plasticity at the mossy fiber synapse onto parvalbumin-expressing basket and axo-axonic cells in the dentate gyrus

doi: 10.3389/fnsyn.2025.1656759

Figure Lengend Snippet: Postsynaptic GABA B Rs modulate synaptic plasticity by activating Kir3 channels. (A) Schematic of targets of baclofen and SCH on the GABA B R-Kir3 molecular complex. Baclofen is an agonist of GABA B Rs, acting at GABA B1 R subunit that leads to activation of the Kir3 channel causing it to open and allowing outflow of K + ions. SCH targets directly the Kir3 channel to prevent its opening. (B) Time course plot of EPSP amplitudes (binned per minute) before and after theta-burst LTP induction protocol was applied in baclofen conditions (14 PV-INs, orange open circles) and in the presence of SCH co-applied with baclofen (6 PV-INs, green open circles). Dashed line represents the mean level of LTP in control conditions (23 PV-INs). Insets, representative EPSPs (averages of 10 individual traces) acquired before (Baseline; thin lines) and 25–30 min after induction (LTP; thick lines) in the presence of baclofen (left) or SCH (right). (C) Summary plot of the mean EPSP amplitudes between 25–30 min after the induction protocol (LTP) in baclofen (14 PV-INs) and SCH (6 PV-INs) conditions. Violin plots show median as solid line and upper and lower quartiles as dotted lines.

Article Snippet: To test the involvement of Kir3 channels, we preapplied the Kir3 channel blocker SCH-23390 (SCH; 10 μM; TOCRIS) to the aCSF.

Techniques: Activation Assay, Control

Journal: Developmental biology

Article Title: Genetic Dissection of Midbrain Dopamine Neuron Development in vivo

doi: 10.1016/j.ydbio.2012.09.019

Figure Lengend Snippet: Quantification of cells in control and mutant mice reveals significant differences in the average number of TH+ and double positive neurons in the VTA and SNc. The average number of TH+ neurons and the 95% confidence intervals of counts from the VTA (A, B) and SNc (C, D) of control (dark grey shaded bars) and mutant mice (dark brown bars) in ventral, intermediate and dorsal planes. (A) The average number of TH+/Calb+ neurons in the VTA of mutant mice (light brown bars) was significantly lower than that of control mice (light grey bars) in all planes quantified. Calb+ neurons in the VTA indicated that the medial domain was not devoid of cells. (B) There were no double immunolabeled TH+/GIR2K+ neurons observed in the ventral VTA of any of the mutant GIRK2-stained slices consistent with the loss of VTA. (C) Although TH+ neurons were diminished in SNc, the average number of TH+/Calb+ neurons in the SNc was not significantly different between controls (light grey bars) and mutants (light brown bars) at any of the three horizontal planes. The blue arrowheads points to the average of TH+/Calb+ neurons. (D) The average number of TH+/GIRK2+ neurons in the SNc of mutant mice was significantly lower than that of control mice in all planes quantified. Images in A, C display TH+ (green), Calb+ (red) and TH+/Calb+ (yellow) cells while images in B, D display TH+ (green), GIRK2+ (red) and TH+/GIRK2+ (yellow) cells. Gray shading of bars indicates data from control animals with dark gray bars corresponding to average TH+ cell counts and nested light gray bars corresponding to average double positive cell counts. Brown shading indicates data from mutant animals with dark brown bars corresponding to average TH+ cell counts and nested lighter brown bars corresponding to average double positive cell counts.

Article Snippet: Calb indin (CALB) and g -protein i nward r ectifying potassium ( K ) channel 2 (GIRK2) were detected with anti-CALB (Swant; 1:1000) or anti-Girk2 (Alomone labs; 1:80), respectively.

Techniques: Mutagenesis, Immunolabeling, Staining

Journal:

Article Title: THE ROLE OF THE NOP RECEPTOR IN REGULATING FOOD INTAKE, MEAL PATTERN, AND THE EXCITABILITY OF PROOPIOMELANOCORTIN NEURONS

doi: 10.1016/j.neuropharm.2010.05.007

Figure Lengend Snippet: The OFQ/N-induced outward current observed in wild type ARC neurons is markedly attenuated by the GIRK channel blocker tertiapin. A, The membrane current trace on the left shows the outward current elicited by 1 µM OFQ/N, which was largely abolished in the presence of tertiapin (10 nM) as evidenced from the trace on the right. B, A bar graph that illustrates the sizable diminution in the OFQ/N-induced change in slope conductance (Δg) estimated by linear regression between −60 to −80 mV, and between −100 and −130 mV, caused by tertiapin. Bars represent the Δg measured in the cell in A between −60 to −80 mV, and between −100 and −130 mV, in the presence of either OFQ/N alone or the combination of tertiapin and OFQ/N. C, Color photomicrographs showing the localization of GIRK1 channel immunoreactivity in the cell in A. The photomicrograph on the left shows the biocytin labeling with streptavidin-AF488. The photomicrograph in the middle shows the GIRK1 channel immunoreactivity as visualized by AF546. The photomicrograph on the right shows the composite overlay. All photomicrographs were shot at 63× magnification. D, This trace shows the lack of an OFQ/N-induced activation of GIRK channels in an ARC neuron from a NOP receptor knockout animal.

Article Snippet: After localizing the biocytin-filled neuron via fluorescence microscopy, the slides containing the appropriate sections were processed with polyclonal antibodies directed against either the NOP receptor (Santa Cruz Biotechnology, Inc., Santa Cruz, CA, USA; 1:500 dilution), the K ir 3.1 (GIRK1) channel (Alomone; 1:200 dilution), cocaine-amphetamine regulated transcript (CART; Phoenix Pharmaceuticals, Inc., Belmont, CA, USA; 1:2000 dilution) or α–MSH (Immunostar, Inc., Hudson, WI, USA; 1:200 dilution) using fluorescence immunohistochemistry ( Ronnekleiv et al., 1990 ).

Techniques: Labeling, Activation Assay, Knock-Out