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.
Profiling Voltage-gated Potassium Channel mRNA Expression in Nigral Neurons using Single-cell RT-PCR Techniques
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.
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.
Simultaneous Multicolor Imaging of Biological Structures with Fluorescence Photoactivation Localization Microscopy
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.
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
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
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.
1Programa de Pós-Graduação em Ciências Médica, Universidade Federal do Rio Grande do Sul, 2Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES), 3Laboratory of Neuromodulation, Department of Physical Medicine & Rehabilitation, Spaulding Rehabilitation Hospital and Massachusetts General Hospital, Harvard Medical School, 4De Montfort University
Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique that has shown initial therapeutic effects in several neurological conditions. The main mechanism underlying these therapeutic effects is the modulation of cortical excitability. Therefore, online monitoring of cortical excitability would help guide stimulation parameters and optimize its therapeutic effects. In the present article we review the use of a novel device that combines simultaneous tDCS and EEG monitoring in real time.
Published June 17, 2013. Keywords: Behavior, Medicine, Neuroscience, Neurobiology, Anatomy, Physiology, Biomedical Engineering, Psychology, electroencephalography, electroencephalogram, EEG, transcranial direct current stimulation, tDCS, noninvasive brain stimulation, neuromodulation, closed-loop system, brain, imaging, clinical techniques
Isotachophoresis (ITP) is a robust electrokinetic separation and preconcentration technique with applications ranging from toxin detection to sample preparation. We review the physical principles of ITP and the methodology of applying this technique to two specific example applications: separation and detection of small molecules and purification of nucleic acids from cell culture lysate.
1Division of Biomedical Engineering, Department of Medicine, Brigham and Women's Hospital, 2Center for Regenerative Therapeutics, Brigham and Women's Hospital, 3Harvard Medical School, Harvard University, 4Harvard Stem Cell Institute, Harvard University, 5Harvard-MIT Division of Health Sciences and Technology, 6Department of Mechanical Engineering, Massachusetts Institute of Technology
This study used a multi-well plate microfluidic system, significantly increasing throughput of cell rolling studies under physiologically relevant shear flow. Given the importance of cell rolling in the multi-step cell homing cascade and the importance of cell homing following systemic delivery of exogenous populations of cells in patients, this system offers potential as a screening platform to improve cell-based therapy.