Figure: Photostimulation of the MNI-Glu-TFA close to the dendritic segment of a hippocampal interneuron. The near simultaneous stimulation and the imaging are accomplished by point and line scanning, respectively. The stimulation is performed in the distributed points, and the evoked changes is followed along a line covering the dendrite. Ca2+ responses along the selected dendritic segment are analyzed as the ∆F/F ratio of OGB-1 fluorescence.
FemtoS-Galvo equipped with Multiple beam moduleThe accuracy of the excitation point and the high flexible scanning patterns enables the FemtoS-Galvo equipped by Multiple beam module to be the best choice for performing uncaging experiments. Multiple point scanning performed by galvo scanner allows stimulation in points around dendrites or even around spines, multiple line scanning along the dendrite allows following the evoked changes with high speed and high SNR. (Femto2D-Galvo equipped with multiple beam module is still an existing opportunity.)
Uncaging in well-defined points of a specimen
The accuracy of the uncaging and imaging is established by the followings:
- the stimulating laser is focused on femtoliter excitation volume
- the galvanometric scanner ensures microsecond-precision
- MES control software allows flexible spatiotemporal scanning
Stimulus mapping and analysis software module
Specialized functions for photostimulation mapping
This module of MES control software allows performing photostimulation mapping experiments at a range of locations and shapes. The locations can be picked manually one-by-one, along a line or in a raster, and various stimulation patterns can be selected like point, spiral, x, zigzag. It forms datasets quickly by evaluating fluorescence changes images at defined time intervals. Analysis tool for stimulation mapping can create (multichannel) map images formed by the elicited responses after a mapping experiment.
- photostimulation at 740 nm with femtosecond IR laser
- high quantum yield
- low effective concentration
- exists as trifluoroacetic acid salted form
- seven-fold higher quantum yield than other caged form
- high excitatory postsynaptic potential (EPSP) and high calcium transient as a response of the photorelease
- lighter illumination sufficient to elicit the same response as with alternative compounds
- eliciting large transients or regenerative activity
- multiple illumination of the same structure
- receptor mapping experiments
- primarily used for in vitro experiments
- TFA salt of compound ensures good solubility, stability and low hygroscopicity of the complex
Femtonics has aimed to design and develop new caged-neurotransmitters for the frontier neuroscience research for custom order. Feel free to contact us if you have an unmatched need or want to test pre-release compounds. See more.
Nonlinear signal integration in interneuron dendrites through dendritic NMDA spikes. A) Maximum intensity image stack projection (top), single scan images showing the maximal 22 locations used for two-photon glutamate uncaging for the clustered (middle) and distributed input patterns (bottom). B) Representative uncaging-evoked 3D Ca2+ responses when the maximum number of inputs was activated for clustered (top) and distributed input patterns (upper middle) decreased to noise level by the NMDA receptor antagonist AP5 (Lower Middle). C) Spatial distribution of the peak 3D Ca2+ responses in (B).
Effect of VGCC blockers on uncaging-evoked Ca2+ responses in an FS-PV IN. A) Maximum intensity z projection image of a distal dendritic segment. Average uncaging-evoked Ca2+ responses in control conditions (middle) and in the presence of a cocktail of VGCC blockers (bottom). White points are active input locations used for DNI-Glu,TFA uncaging (top). B) Spatial distribution of the peak dendritic Ca2+ response measured along the white line in (A) under control conditions (black) and in the presence of VGCC blockers (red). Inset: mean Ca2+ transients derived from the hot spot (green) and lateral dendritic (magenta) regions before (solid line) and after (dashed line) application of the VGCC cocktail.
Comparison of eEPSPspine (red) and eEPSPdendrite (green) evoked by two-photon uncaging of glutamate. Lower black traces: somatic patch electrode recordings and timing of uncaging pulse. Left panels: upper shows z-stack of confocal images, lower is a single frame image of a spine in recording position, red dot: uncaging location.
Cell-type–specific inhibition of the dendritic plateau potential in striatal spiny projection neurons. Kai Du, Yu-Wei Wu, Robert Lindroos, Yu Liu, Balázs Rózsa, Gergely Katona, Jun B. Ding, and Jeanette Hellgren Kotaleski, PNAS (2017)
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Local Postsynaptic Voltage-Gated Sodium Channel Activation in Dendritic Spines of Olfactory Bulb Granule Cells Wolfgang G. Bywalez, Dinu Patirniche, Vanessa Rupprecht, Martin Stemmler, Andreas;V.M. Herz, Denes Palfi, Balazs Rozsa, Veronica Egger, Neuron (2015)
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Combined two-photon imaging, electrophysiological, and anatomical investigation of the human neocortex in vitro. Balint Peter Kerekes, Kinga Toth, Attila Kaszas, Balazs Chiovini, Zoltan Szadai, Gergely Szalay, Denes Palfi, Attila Bago, Klaudia Spitzer, Balazs Rozsa, Istvan Ulbert, Lucia Wittner, Neurophotonics (2014)
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