Invention novelty:
Primary sensory neurons in the DRG play essential role in initiating somatosensory such as pain, itch, and touch by directly sensing various sensory stimuli like mechanical, chemical, and thermal stimuli. Dysfunction of these neurons often leads to various pathological conditions including chronic pain and itch. Currently, no one has developed a method to study DRG neuron activity at populational level prior to development by JHU researchers.
Abstract:
Johns Hopkins researchers have generated Pirt-GCaMP3 mice in which the genetic encoded calcium indicator, GCaMP3, is expressed specifically in nearly 100% of primary sensory neurons in the dorsal root ganglion (DRG). Pirt-GCaMP3 mice allow for monitoring of the activation of pain-sensing neurons in tissue explants such as skin nerves, DRG, and sensory nerves in the spinal cord. They also can be used to image DRG neuron activities in live mice. Therefore, Pirt-GCaMP3 mice are powerful tool to study somatosensation such as pain, itch, and touch.
Description Details:
Johns Hopkins researchers have generated Pirt-GCaMP3 mice in which GCaMP3, a genetic-encoding Ca2+ sensitive indicator, is expressed robustly and specifically in almost all primary sensory neurons. The advantages of GCaMP3 imaging using these mice are manifold: simple tissue preparation and imaging procedures; excellent spatial resolution; sensitive, high-efficiency simultaneous imaging of multiple neurons; and preservation of somatotopic organization. Because of these advantages, we were able to readily visualize peripheral neuronal hypersensitivity in both injured and uninjured tissues corresponding to primary and secondary hyperalgesia, respectively. Strikingly, hypersensitivity was present not only in peripheral fibers in the skin and cell bodies but also in the central terminals. More importantly, there was a development of a procedure to image DRG neuron activities in live Pirt-GCaMP3 mice. Using this powerful and novel technique, the researchers have revealed several important and novel pain mechanisms. In addition, these mice are extremely useful for evaluating anti-pain and itch drugs.
Publication(s)/Associated Cases:
