TY - JOUR
T1 - Large scale in vivo recording of sensory neuron activity with GCaMP6
AU - Chisholm, Kim Imogen
AU - Khovanov, Nikita
AU - De Medeiros Lopes, Douglas
AU - La Russa, Federica
AU - McMahon, Stephen
PY - 2018/2/28
Y1 - 2018/2/28
N2 - Greater emphasis on the study of intact cellular networks in their physiological environment has led to rapid advances in intravital imaging in the central nervous system, while the peripheral system remains largely unexplored. To assess large networks of sensory neurons we selectively label primary afferents with GCaMP6s in male and female C57bl/6 mice and visualise their functional responses to peripheral stimulation in vivo. We show that we are able to monitor the activity of hundreds of sensory neurons simultaneously, with sufficient sensitivity to detect, in most cases, single action potentials with a typical rise time of around 200 milliseconds, and an exponential decay with a time constant of approximately 700 milliseconds. With this technique we are able to characterise the responses of large populations of sensory neurones to innocuous and noxious mechanical and thermal stimuli under normal and inflammatory conditions. We demonstrate that the majority of primary afferents are polymodal with between 50-80% of thermally sensitive DRG neurons responding also to noxious mechanical stimulation. We also specifically assess the small population of peripheral cold neurons and demonstrate significant sensitisation to cooling after a model of sterile and persistent inflammation, with significantly increased sensitivity already at decreases of 5°C when compared to uninflamed responses. This not only reveals interesting new insights into the (patho)physiology of the peripheral nervous system but also demonstrates the sensitivity of this imaging technique to physiological changes in primary afferents.
AB - Greater emphasis on the study of intact cellular networks in their physiological environment has led to rapid advances in intravital imaging in the central nervous system, while the peripheral system remains largely unexplored. To assess large networks of sensory neurons we selectively label primary afferents with GCaMP6s in male and female C57bl/6 mice and visualise their functional responses to peripheral stimulation in vivo. We show that we are able to monitor the activity of hundreds of sensory neurons simultaneously, with sufficient sensitivity to detect, in most cases, single action potentials with a typical rise time of around 200 milliseconds, and an exponential decay with a time constant of approximately 700 milliseconds. With this technique we are able to characterise the responses of large populations of sensory neurones to innocuous and noxious mechanical and thermal stimuli under normal and inflammatory conditions. We demonstrate that the majority of primary afferents are polymodal with between 50-80% of thermally sensitive DRG neurons responding also to noxious mechanical stimulation. We also specifically assess the small population of peripheral cold neurons and demonstrate significant sensitisation to cooling after a model of sterile and persistent inflammation, with significantly increased sensitivity already at decreases of 5°C when compared to uninflamed responses. This not only reveals interesting new insights into the (patho)physiology of the peripheral nervous system but also demonstrates the sensitivity of this imaging technique to physiological changes in primary afferents.
UR - http://www.scopus.com/inward/record.url?scp=85045665784&partnerID=8YFLogxK
U2 - 10.1523/ENEURO.0417-17.2018
DO - 10.1523/ENEURO.0417-17.2018
M3 - Article
SN - 2373-2822
VL - 5
JO - eNeuro
JF - eNeuro
IS - 1
M1 - NEURO.0417-17.2018
ER -