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Show 158 A STEP IN UNDER-STANDING PAIN SIGNALING FROM THE PERIPHERAL NERVOUS SYSTEM Jeffrey Cox (Russell Teichert, Baldomero Olivera) Department of Biology University of Utah Salt Lake City research posters on the hill spring 2012 Classifying Neuronal Subtypes of PNS to Better Understand Pain Jeffrey Cox and Russell Teichert Department of Biology Student Photo Faculty Photo Jeffrey Cox Russell Teichert Adapted from Teichert et al. 2012 Stain = Fura 2AM Calcium Imaging Platform A B Identifying the Menthol/Cold Sensitive cells Image was addapted from <http://www.nature.com/nrn /journal/v9/n10/images/nrn2493-f2.jpg> et al. 2012 BF 380 C E M+A+ M+A-M+ A+ M+A-M+ A+ M+A+ The Locus of interest Understanding which Ca++ Channels are expressed in "Noxious Cold" Vs "Cold" neurons Different Voltage-Gated Calcium Channel Blockers Dorsal Root Ganglia of the Lumbar region Neurons were dissociated for imaging D M+A-M+ A+ M+A-Application: Understanding of these Menthol/Cold sensitive neurons will help us to better understand conditions such as Cold Allodynia and Cold hyperalgesia. Whats Next? Expand on the knowledge of Menthol/Cold sensitive neurons to better understand pain sensation through the Peripheral Nervous System. nicardipine was used to block L-type Calcium Channels. omega-conotoxin MViiC (from cone-snail venom) & snX-482 (from spider venom) together block n, p/Q & r-type Calcium Channels. The combination of nicardipine, MViiC and snX-482 was used to block L-, n-, p/Q-, & r-type Calcium channels. omega-gViA (from cone-snail venom) and nicardipine Menthol Block with nicardipine GM48677 The goal of our research is to understand pain signaling in the peripheral nervous system. As a first step, we are focused on identifying and characterizing the different subtypes of sen sory neurons present in the dorsal-root ganglia (DRG) of mice. To do so, we couple calcium imaging with pharmacology to identify the constellations of receptors and ion channels functionally expressed in the plasma membranes of these neurons, including ligand- and voltage-gated ion channels, GPCRs, etc. The calcium- imaging platform allows us to moni-tor the cellular responses to pharmacological agents from >100 individual neurons simultaneously. The calcium signal that we monitor is a measurement of the cytoplasmic calcium concentration before and after a stimulus or challenge with a pharmacological agent. The neuronal responses to various chal-lenge compounds help us to identify the receptors and ion channels expressed in particular cells. By this method, we have identified and characterized two types of cold-sensitive neurons: one appears to detect innocuous cool temperatures while the other probably detects noxious, painful cold temperatures. Using functional markers, we can identify these neuronal subtypes in the population of DRG cells, e.g. one sub-type responds to ATP, menthol and mustard oil, while the other responds only to menthol. I am performing experiments to characterize the different types of voltage-gated calcium channels expressed in these cold-sensitve neurons (e.g. L-, N-, P/Q-, R- and T-type calcium channels). We plan to explore the other classes of receptors and ion channels expressed in these subtypes of cold-sensitive neurons, and we plan to expand this type of characterization to other DRG neuronal subtypes. Thus we can potentially identify and charac-terize all of the different subtypes of DRG neurons involved in detecting and transmitting sensory informa-tion from the periphery to the brain. |