Edgar T. Walters, Ph.D.
1980, Columbia University
UT-Houston Medical School
Integrative Biology and Pharmacology
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Edgar T. Walters, Ph.D. 1980, Columbia University UT-Houston Medical School |
Research Interests: Neuronal injury, pain, and memory
We explore adaptive responses of neurons to injury and stress in invertebrate and mammalian preparations, looking for potentially ancient links between these responses and fundamental mechanisms important for pain and memory. Some of our work utilizes a marine snail, Aplysia, whose large, accessible neurons enable single-cell experimental manipulations (electrical and molecular) and which allow us to define the role of individual cells and their alterations in an animal’s behavior. For example, intracellular injection has been used to investigate contributions of the cAMP-PKA-CREB and NO-cGMP-PKG pathways to long-term hyperexcitability of the cell bodies of nociceptors. Electrophysiological and pharmacological methods are being used to study contributions of local, rapamycin-sensitive protein synthesis to long-term hyperexcitability of the axons of nociceptors. A novel discovery is that long-term axonal hyperexcitability can be induced by mechanisms that depend upon local depolarization but not calcium signals. New studies are examining long-term hyperexcitability in nociceptors of the rat following spinal cord injury and other stresses. Three preparations are used because of their complementary advantages for revealing fundamental mechanisms and functions of injury-related plasticity: rat dorsal root ganglion neurons, Aplysia nociceptors and motor neurons, and the giant axon of the squid. Tutorials can combine varied techniques, including intracellular recording, whole-cell and axial voltage clamping, microscopy, controlled intracellular or extracellular delivery of cellular messengers or their antagonists, cell and organ culture methods, in situ hybridization, biochemical assays, and sophisticated methods for probing behavioral responses of invertebrate and vertebrate animals.
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Lewin MR, Walters ET (1999) Cyclic GMP pathway is critical for inducing long-term sensitization of nociceptive sensory neurons. Nat Neurosci, 2:18–23.
Walters ET, Bodnarova M, Dulin MF, Diaz-Rios M, Miller MW, Moroz LL (2004) Somatotopic organization and functional properties of mechanosensory neurons expressing sensorin-A mRNA in Aplysia californica. J Comp Neurol 471:219-240.
Sung YJ, Walters ET, Ambron RT (2004) Retrograde axonal transport of a neuronal isoform of PKG couples MAPK nuclear import to axotomy-induced long-term hyperexcitability in Aplysia sensory neurons. J Neurosci, 24:7583-7595.
Weragoda RMS, Ferrer E, Walters ET (2004) Memory-like alterations in Aplysia axons following localized nerve depolarization or injury. J Neurosci, 24:10393-10401.
Gasull X, Liao X, Dulin MF, Phelps C, Walters ET (2005) Evidence that long-term hyperexcitability of the sensory neuron soma induced by nerve injury is adaptive. J. Neurophysiol. 3:2218-2230.
Song XJ, Wang ZB, Gan Q, Walters ET (2006) cAMP and cGMP contribute to sensory neuron hyperexcitability and hyperalgesia in rats with dorsal root ganglia compression. J Neurophysiol, 95:479-492.
Zheng JH, Walters ET, Song XJ (2006) Dissociation of dorsal root ganglion neurons induces hyperexcitability that is maintained by increased responsiveness to cAMP and cGMP. J Neurophysiol , 97:15-25.
Weragoda RMS, Walters ET (2007) Serotonin induces memory-like, rapamycin-sensitive hyperexcitability in sensory axons of Aplysia that contributes to injury responses. J. Neurophysiol, 98:1231-1239.
Program Affiliations:
Program in Cell and Regulatory
Biology (Physiology Track)
Program in Neuroscience