Calcium Signaling in Peripheral Sensory Nerve Endings

项目总结

PROJECT SUMMARY Millions of Americans suffer from unrelenting chronic pain conditions that are resistant to existing treatments, and those who turn to opioid medication can develop dependencies that are devastating and life threatening. There is essential need for more effective, non-addictive analgesics with limited side effects. Voltage-gated calcium (CaV) channels are potential targets for improved pain therapeutics. CaV channels are critical in altering sensory neuron sensitivity and in transmitting information about noxious stimuli. Changes in sensitivity of sensory neurons to stimuli – such as heat and touch - can result in transient forms of hypersensitivity and, if the stimulus is prolonged or especially intense, more prolonged hypersensitivity, which can lead to chronic pain. CaV channels in the spinal cord are important for the induction and maintenance of hypersensitivity, but the Lipscombe lab has recently shown that peripheral CaV2.2 channels in heat sensing neurons in skin are also critical for this process. This proposal will expand this discovery to investigate the functional contribution of peripheral CaV channels to hypersensitivity in Trpv1-nociceptor and Aδ low threshold mechanoreceptor (Aδ LTMR) nerve endings in skin. In Aim 1, optogenetics and automated, real-time behavior tracking with high-speed videography will be combined to assess behavioral responses induced by direct activation of either Trpv1-nociceptor (heat-sensing) or Aδ LTMRs (mechano-sensing). Changes in evoked behavior will be assessed following sensitization of either neuron population as well as the potential for selective inhibition of peripheral CaV channels to attenuate these outputs. Aim 2 will investigate intracellular calcium dynamics in nerve endings in skin associated with the development of hypersensitivity. Integration of optogenetics, 2-photon in vivo calcium imaging, and pharmacology, will uncover the individual contribution of CaV2.2 and CaV3.2 channels to calcium events in Trpv1-nociceptor and Aδ LTMRs that trigger hypersensitivity. This work will provide unique data on the role of peripheral CaV channels in the induction of hypersensitivity and may identify novel sites of action for developing more effective pain therapeutics, thereby reducing unwanted side effects from actions in the central nervous system. The proposed research builds on the applicant’s experience and provides an opportunity to develop unique expertise in genetic, behavioral, 2- photon imaging and computation techniques. Collaborating with the Fleischmann and Moore labs for 2- photon calcium imaging gives the applicant essential experience in team science and integrating across different levels of investigation. This fellowship will also support the applicant’s professional development in rigorous scientific methods and effective scientific communication. The Brain Science environment at Brown University is exceptional for training, it provides numerous avenues for support, training, and resources to prepare the applicant for a career as an independent academic scientist.