Editor
Geoffrey C. Y. Lau
  • Faculty, Department of Neuroscience, City University of Hong Kong
Research fields
  • Neuroscience
Implanting and Recycling Neuropixels Probes for Recordings in Freely Moving Mice
Authors:  Ashley L. Juavinett, George Bekheet and Anne K. Churchland, date: 02/05/2020, view: 6136, Q&A: 0
Recording neural activity in unrestricted animals is necessary to unravel the neural basis of ethological behaviors. Recently, Neuropixels probes have made important strides in improving yield and lowering noise, but have limited use cases in freely moving animals. Although there are a number of studies demonstrating the use of these probes in headfixed mice, there are not established protocols for the use and reuse of them in a freely moving mouse. We therefore designed a novel device (the AMIE) that maximizes the potential value of these powerful probes. Here, we provide the technical drawings for the AMIE and detail its preparation, implantation, and explantation. With our approach, researchers can record hundreds of neurons during freely moving behavior across weeks of experiments, and then recycle valuable probes for future use.
Semi-automated Model to Accurately Counting Sympathetic Nervous Fibers
Authors:  Dennis Bleck, Lkham Erdene-Byambadoo, Ralph Brinks, Matthias Schneider and Georg Pongratz, date: 12/20/2019, view: 3870, Q&A: 0
In recent years, the role of sympathetic nervous fibers in chronic inflammation has become increasingly evident. At the onset of inflammation, sympathetic activity is increased in the affected tissue. However, sympathetic fibers are largely absent from chronically inflamed tissues. Apparently, there is a very dynamic relationship between sympathetic innervation and the immune system in areas of inflammation, and hence a rapid and easy method for quantification of nerve fiber density of target organs is of great value to answer potential research questions. Sympathetic nerve ends lie in close proximity to immune cells in lymphoid tissues and lymphoid cells are equipped with catecholamine receptors. Catecholamines such as dopamine and adrenaline are secreted by sympathetic nervous fibers and can influence immune cell activity directly. Thereby the sympathetic nervous system immediately participates in the regulation of inflammation. Changes in innervation density could therefore indicate dysregulation of inflammatory processes. Currently, nervous fiber densities are either determined by tedious manual counting, which is not suitable for high throughput approaches, or by expensive automated processes relying on specialized software and high-end microscopy equipment. Usually, tyrosine hydroxylase (TH) is used as the marker for sympathetic fibers. In order to overcome the current quantification bottleneck with a cost-efficient alternative, an automated process was established and compared to the classic manual approach of counting TH-positive sympathetic fibers. Since TH is not exclusively expressed on sympathetic fibers, but also in a number of catecholamine-producing cells, a prerequisite for automated determination of fiber densities is to reliably distinguish between cells and fibers. Therefore, an additional stain using peripherin which is exclusively expressed in nervous fibers as a secondary marker was established. This new and simple method can be used as a high-throughput approach to reliably and quickly estimate sympathetic nervous system (SNS) nerve fiber density in target tissues.
Cylinder Test to Assess Sensory-motor Function in a Mouse Model of Parkinson’s Disease
Parkinson’s disease is a progressive neurodegenerative movement disorder that happens due to the loss of dopaminergic neurons in the substantia nigra. The deficiency of dopamine in the basal nuclei drives cardinal motor symptoms such as bradykinesia and hypokinesia. The current protocol describes the cylinder test, which is a relatively simple behavioral assessment that evaluates the motor deficits upon unilateral degeneration of the nigrostriatal pathway in experimental models of Parkinson’s disease. Since dopamine-depleted mice exhibit the preferential use of the forelimb ipsilateral to the lesion, here researchers perform the cylinder test to investigate the therapeutic effects of antiparkinsonian treatments on the performance of the contralateral (injured) limb.
A Mouse Model of Postoperative Pain
Authors:  Ashley M. Cowie and Cheryl L. Stucky, date: 01/20/2019, view: 7936, Q&A: 0
Postoperative pain is highly debilitating and hinders recovery. Opioids are the main pain medication used for acute postoperative pain. Given the devastating opioid addiction and overdose epidemic across the US, non-opioid pain therapeutics are desperately needed. In order to develop novel, non-opioid therapies for the treatment of postoperative pain and identify the mechanisms underlying this pain, rodent models of incisional pain have been established. The protocol herein describes in detail how to create a mouse model of postoperative pain that was adapted from established protocols. This model of postoperative pain is frequently-used, highly reproducible, and results in peripheral and central nervous system alterations.
Primary Culture of Mouse Neurons from the Spinal Cord Dorsal Horn
Authors:  De-Li Cao, Peng-Bo Jing, Bao-Chun Jiang and Yong-Jing Gao, date: 01/05/2017, view: 15923, Q&A: 0
Primary afferents of sensory neurons mainly terminate in the spinal cord dorsal horn, which has an important role in the integration and modulation of sensory-related signals. Primary culture of mouse spinal dorsal horn neuron (SDHN) is useful for studying signal transmission from peripheral nervous system to the brain, as well as for developing cellular disease models, such as pain and itch. Because of the specific features of SDHN, it is necessary to establish a reliable culture method that is suitable for testing neural response to various external stimuli in vitro.
Isolating Taste Buds and Taste Cells from Vallate Papillae of C57BL/6J Mice for Detecting Transmitter Secretion
Authors:  Anthony Y. Huang and Sandy Y. Wu, date: 06/05/2016, view: 8772, Q&A: 0
Mouse is a well-accepted model for studying taste bud function. Mice readily detect and respond to taste substances that humans consider to have sweet, bitter, salty, sour and umami taste qualities. A great deal of recent research on taste receptors is based on this species. Live mice are needed for these experiments because no alternative in vitro model incorporates all elements of taste transduction and peripheral signaling. The C57BL/6J strain was selected because these mice respond robustly to many taste stimuli and because of variety of transgenic animals, such as PLCβ2-GFP and GAD67-GFP, were derived from that strain. Prior analyses on behavior, nerve responses, cellular electrophysiology and molecular biology, all conducted on C57BL/6J mice will form a solid foundation for the proposed studies (Finger et al., 2005; Huang and Wu, 2015; Huang et al., 2007). Thus, freshly euthanized animals must be used as a source of taste buds from which we will isolate taste buds and taste cells.
Aβ Extraction from Murine Brain Homogenates
Authors:  Brad T. Casali and Gary E. Landreth, date: 04/20/2016, view: 10909, Q&A: 0
This protocol details beta-amyloid (Aβ) extraction from transgenic murine brain homogenates. Specifically, mechanical homogenization of brain tissue and sequential extraction of both soluble and insoluble proteins are detailed. DEA extracts soluble proteins, such as Aβ isoforms and APP. Formic acid enables extraction of insoluble protein aggregates, such as Aβ isoforms associated with plaques. This procedure produces soluble and insoluble extracts that are amenable to analysis of Aβ species via western blotting and/or enzyme-linked immunosorbent assays (ELISAs), and these results help assess amyloidogenic burden in animals.
Chick Neural Tube Explant Culture
Authors:  Zhanna Alekseenko, Elisabet Andersson and José M. Dias, date: 10/05/2015, view: 9982, Q&A: 0
The neural tube explant culture technique allows in vitro culturing of small pieces of neural tissue isolated from e.g., chick or mouse embryonic tissue in a matrix of collagen for defined periods of time. This method can be used to study the effects of defined molecules on developmental processes such as neural progenitor proliferation and neuronal differentiation and/or survival. Since the explant material can also be prepared from embryonic tissue electroporated with expression vectors, this technique can be adapted to study gene function in the presence of specific environmental signals. Different regions of the neural tube can also be isolated during the dissection step, allowing specific regions of the neural tube to be studied separately. Here, we present a neural tube explant culture method that we have used in several studies (Dias et al., 2014; Lek et al., 2010; Vallstedt et al., 2005).
Fluorescent Measurement of Synaptic Activity Using SynaptopHluorin in Isolated Hippocampal Neurons
Authors:  Hongmei Li, Han-A Park and Elizabeth A. Jonas, date: 12/05/2014, view: 11156, Q&A: 0
This protocol comprises the entire process of fluorescent measurement of vesicle recycling using the probe SynaptopHluorin, a pH-dependent GFP variant whose fluorescence increases at the synapse upon vesicle release due to fluorescence quenching in acidic vesicles. This technique provides a genetic tool to monitor synaptic vesicle recycling in real time in cultured hippocampal neurons.
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