1Institut für Zelluläre und Molekulare Physiologie, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU)
Proteolytic activation of the epithelial sodium channel (ENaC) heterologously expressed in Xenopus laevis oocytes can be demonstrated by combining current measurements with a biotinylation approach to investigate the appearance of ion channel cleavage products at the cell surface. Functionally important cleavage sites can be identified by using site-directed mutagenesis.
Published July 5, 2014. Keywords: Biochemistry, two-electrode voltage-clamp, electrophysiology, biotinylation, Xenopus laevis oocytes, epithelial sodium channel, ENaC, proteases, proteolytic channel activation, ion channel, cleavage sites, cleavage fragments
1Department of Neuroscience, Uppsala University, Sweden
We use the patch-clamp technique to measure GABA-activated single-channel currents (GABAA channels, GABAA receptors) and the synaptic and tonic currents they generate in neurons. Activation of the channels decreases neuronal excitability in health and disease 1,2,3,4.
Published July 17, 2011. Keywords: Neuroscience, brain, patch-clamp, ion channels, tonic current, slices, whole-cell current, single-channel current, GABAA, GABA
1Department of Pharmacology, University of Tennessee College of Medicine
Neurons are first characterized electrophysiologically. Then the cytoplasm from the recorded neuron is aspirated and subjected to reverse transcription-PCR analysis to detect the expression of mRNAs for neurotransmitter synthesis enzymes, ion channels, and receptors.
Published September 27, 2011. Keywords: Neuroscience, action potential, mRNA, patch clamp, single cell RT-PCR, PCR, substantia nigra
1Department of Biomedical Engineering, Washington University in St. Louis
The cut-open Vaseline gap approach is used to obtain low noise recordings of ionic and gating currents from voltage-dependent ion channels expressed in Xenopus oocytes with high resolution of fast channel kinetics. With minor modification, voltage clamp fluorometry can be coupled to the cut-open oocyte protocol.
Published March 11, 2014. Keywords: Developmental Biology, Voltage clamp, Cut-open, Oocyte, Voltage Clamp Fluorometry, Sodium Channels, Ionic Currents, Xenopus laevis
1Department of Physics and Astronomy, University of Maine
We demonstrate the use of fluorescence photo activation localization microscopy (FPALM) to simultaneously image multiple types of fluorescently labeled molecules within cells. The techniques described yield the localization of thousands to hundreds of thousands of individual fluorescent labeled proteins, with a precision of tens of nanometers within single cells.
Published December 9, 2013. Keywords: Basic Protocol, Microscopy, Super-resolution imaging, Multicolor, single molecule, FPALM, Localization microscopy, fluorescent proteins
1Department of Pharmacology, Vanderbilt University School of Medicine, 2Department of Anesthesiology, Vanderbilt University School of Medicine, 3Vanderbilt Institute of Chemical Biology, Vanderbilt University School of Medicine
Methods for developing and validating a quantitative fluorescence assay for measuring the activity of inward rectifier potassium (Kir) channels for high-throughput compound screening is presented.
Published January 27, 2013. Keywords: Biochemistry, Molecular Biology, Chemistry, Cellular Biology, Chemical Biology, Pharmacology, Molecular Pharmacology, Potassium channels, drug discovery, drug screening, high throughput, small molecules, fluorescence, thallium flux, checkerboard analysis, DMSO, cell lines, screen, assay, assay development
1Neurobiology, NCBS-TIFR, 2Department of Biological Sciences, TIFR
A simple microfluidic device has been developed to perform anesthetic free in vivo imaging of C. elegans, intact Drosophila larvae and zebrafish larvae. The device utilizes a deformable PDMS membrane to immobilize these model organisms in order to perform time lapse imaging of numerous processes such as heart beat, cell division and sub-cellular neuronal transport. We demonstrate the use of this device and show examples of different types of data collected from different model systems.
Published September 30, 2012. Keywords: Bioengineering, Molecular Biology, Neuroscience, Microfluidics, C. elegans, Drosophila larvae, zebrafish larvae, anesthetic, pre-synaptic vesicle transport, dendritic transport of glutamate receptors, mitochondrial transport, synaptotagmin transport, heartbeat
1School of Life Sciences, Arizona State University
In situ patch clamp recordings are used for electrophysiological characterization of neurons in intact circuitry. In the Drosophila genetic model patch clamping is difficult because the CNS is small and surrounded by a robust sheath. This article describes the procedure to remove the sheath and clean neurons for subsequent patch clamp recordings.
Published October 15, 2012. Keywords: Neuroscience, Molecular Biology, Cellular Biology, Anatomy, Physiology, Patch clamp, in situ patch clamp, Drosophila, electrophysiology, motoneuron, neuron, CNS
JoVE Clinical and Translational Medicine
1Department of Medicine, Weill Cornell Medical College, 2Department of Urology, Weill Cornell Medical College
Our report describes a unique method to visualize and analyze CTC/EC interactions in prostate cancer under physiological flow conditions.
Published May 15, 2014. Keywords: Medicine, E-selectin, Metastasis, Microslides, Circulating tumor cells, PSMA, Prostate cancer, rolling velocity, immunostaining, HUVECs, flow chambers
1Department of Neurology, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School
Microglia are the resident immune cells of the central nervous system (CNS) with a high capacity to phagocytose or engulf material in their extracellular environment. Here, a broadly applicable, reliable, and highly quantitative assay for visualizing and measuring microglia-mediated engulfment of synaptic components is described.
Published June 8, 2014. Keywords: Neuroscience, Central Nervous System (CNS), Engulfment, Phagocytosis, Microglia, Synapse, Anterograde Tracing, Presynaptic Input, Retinogeniculate System