6/26/2023 0 Comments Mouse brain xsectioncell soma area and axon length), electrophysiology, and protein localisation. Live cultures imaged by phase contrast microscopy c or fixed neurons imaged by confocal microscopy d can be used to assess various cellular phenotypes including morphology (e.g. c, d Representative images of primary DRG sensory neuron cultures 24 h post-plating. The picture depicts the dorsal aspect of the spinal cord and the spinal nerve roots without bilateral DRG for simplicity. b Mice possess 8 cervical, 13 thoracic, 5 or 6 lumbar, and 4 sacral DRG pairs totalling 60 or 62 individual ganglia depending on genetic background. The schematic portrays a transverse section of the spinal column. a DRG are clusters of sensory neuron cell bodies located in the dorsal roots of the spinal column. ĭissected DRG can be enzymatically dissociated and grown in culture or sectioned for immunohistochemical analyses. However, recent single-cell, RNA sequencing experiments indicate that there are potentially 11 distinct afferent subtypes based on discrete molecular identities and function. The diverse repertoire of DRG sensory neuron varieties has been classified based on how cellular characteristics such as electrophysiological properties, growth factor response, morphology, and protein markers relate to function. The distal ends of sensory nerves are consequently specialised, culminating in or synapsing with assorted sense organs adapted to function, for example Pacinian corpuscles for pressure perception or Golgi tendon organs for detecting muscle tension. In order to perceive diverse stimuli from the environment, functional sensory subtypes target different regions of the periphery, for instance proprioceptive neurons, which are important for sensing body position in space, innervate muscle spindles, while temperature-sensing thermoceptive cells often end in the skin. Broad functional classes of sensory neurons connect with distinct regions of the spinal cord, for example pain-sensing nociceptors form synapses predominantly in superficial grey matter laminae (I–II), while touch-sensitive mechanoreceptive neurons typically terminate in deeper laminae (III–V). DRG sensory neurons are pseudo-unipolar, because they have a single axon projecting from the cell body that then bifurcates into two branches that centrally and distally target the dorsal horn of the spinal cord and peripheral tissues, respectively. Located in the dorsal intervertebral foramen adjacent to the spinal cord, dorsal root ganglia (DRG) are heterogeneous collections of sensory neuron cell somas found in pairs at each level of the spinal column (Fig. This approach reduces the time required to collect DRG, thereby improving efficiency, permitting less opportunity for tissue deterioration, and, ultimately, increasing the chances of generating healthy primary DRG cultures or high quality, reproducible experiments using DRG tissue. The process is both faster and less technically challenging than extracting the ganglia from the in situ column after performing a dorsal laminectomy. This protocol allows the easy and rapid isolation of DRG with minimal practice and dissection experience. FindingsĪfter dissecting out the spinal column, from the base of the skull to the level of the femurs, it can be cut down the mid-line and the spinal cord and meninges removed, before extracting the DRG and detaching unwanted axons. Here, we describe a simple, step-by-step protocol for the swift isolation of mouse DRG, which can be enzymatically dissociated to produce fully differentiated primary neuronal cultures, or processed for downstream analyses, such as immunohistochemistry or RNA profiling. Rodent DRG neurons have long been studied in the laboratory to improve understanding of sensory nerve development and function, and have been instrumental in determining mechanisms underlying pain and neurodegeneration in disorders of the peripheral nervous system. The cell bodies of sensory neurons, which transmit information from the external environment to the spinal cord, can be found at all levels of the spinal column in paired structures called dorsal root ganglia (DRG).
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