Susan Ingram, Ph.D.

  • Professor of Neurological Surgery, School of Medicine
  • Program in Molecular and Cellular Biosciences, School of Medicine
  • Neuroscience Graduate Program, School of Medicine
  • Behavioral Neuroscience Graduate Program, School of Medicine


My research is focused on understanding neuronal mechanisms of synaptic plasticity involved in pain and drug addiction circuits. One area of current research is focused on identifying intracellular signaling pathways involved in morphine tolerance and dependence using in vitro brain-slice recordings and in vivo behavioral assays. Our experiments focus on how mu opioid receptors (MOPrs) in the periaqueductal gray area (PAG) modulate neuronal excitability and synaptic transmission of PAG neurons. MOPrs are an integral part of the endogenous descending antinociceptive pathway that decreases pain impulses in the spinal cord. Repeated and continuous opioid administration induces neural changes in this system. A second area of research in my laboratory is the dopamine transporter (DAT) and an associated chloride current that I identified in midbrain dopamine neurons. The DAT is one of a family of transporters that are the main targets for psychostimulants, such as amphetamine and cocaine. These transporters are also targets for therapeutic drugs for disorders including depression and attention deficit disorder. Although the transporters are primarily known for regulating extracellular concentrations of neurotransmitters through reuptake of released neurotransmitters, they have significant electrical activities as well. My recent studies determined that these transporters have a role in modulating excitability of midbrain neurons.


Education and training

    • B.A., 1990, Bowdoin College
    • Ph.D., 1995, Oregon Health & Science University


Selected publications

  • 1.  Underhill, S.M., Hullihen, P., Chen, J., Ferrer, C.F. ,Rizzo, M., Ingram, S.L. and Amara, S.G. (2019). Amphetamines signal through intracellular TAAR1 receptors coupled to Gα13 and GαS in discrete subcellular domains. Molecular Psychiatry, in press.
  • 2.     McPherson, K.B., Leff, E.R., Li, M-H., Meurice, C., Tai, S., Traynor, J.R., Ingram, S.L. (2018). Regulators of G protein Signaling (RGS) proteins promote receptor coupling to G protein-coupled inwardly-rectifying potassium (GIRK) channels. The Journal of Neuroscience, 38(41):8737-8744. PMCID in progress.
  • 3.     Underhill, S.M., Ingram, S.L., Ahmari, S.E., Veenstra-VanderWeele, J., Amara, S.G. (2018). Neuronal excitatory amino acid transporter EAAT3: Emerging functions in health and disease, Neurochemistry International, (18)30139-6. PMCID in progress.
  • 4.     Chen, Q., Roeder, Z., Li, M-H., Zhang, Y.M., Ingram, S.L., Heinricher, M.M. (2017). Optogenetic evidence for a direct circuit linking nociceptive transmission through the parabrachial complex with pain-modulating neurons of the rostral ventromedial medulla (RVM). eNeuro. 4(3). PMCID: PMC5483601
  • 5.      Li, M-H, Underhill, SM, Reed, C, Phillips, TJ, Amara, SG, Ingram, SL. (2017). Amphetamine and methamphetamine increase NMDAR-GluN2B synaptic currents in midbrain dopamine neurons. Neuropsychopharmacology, 42(7):1539-1547. PMCID: PMC5436114.
  • 6.      Li, M-H., Suchland, K.L. Ingram, S.L. (2017). Compensatory activation of cannabinoid CB2 receptor inhibition of GABA release in the rostral ventromedial medulla (RVM) in inflammatory pain. The Journal of Neuroscience, 37(3): 626-636.PMCID: PMC5242409
  • 7.     Tonsfeldt, K.J., Suchland, K.L., Beeson, K.A., Lowe, J.D., Li, M-H., Ingram, S.L. (2016). Sex differences in GABAA signaling in the periaqueductal gray Induced by persistent inflammation. The Journal of Neuroscience, 36(5): 1669-81. PMCID: PMC4737776
  • 8.   Bobeck, E.N., Ingram, S.L., Hermes, S.M., Aicher, S.A., Morgan, M.M. (2016). Ligand-biased activation of extracellular signal-regulated kinase 1/2 leads to differences in opioid induced antinociception and tolerance.Behavioral Brain Research, 298(Pt B): 17–24. PMCID: PMC4779316
  • 9.      Li, M-H., Suchland, K.L., Ingram, S.L. (2014). GABAergic transmission and enhanced modulation by opioids and endocannabinoids in adult rat rostral ventromedial medulla. Journal of Physiology, 593(1): 217-30. PMCID: PMC4293064.
  • 10.      Underhill, S.M., Wheeler, D.S., Li, M., Watts, S.D., Ingram, S.L., Amara, S.G. (2014). Amphetamine modulates glutamatergic neurotransmission through endocytosis of the excitatory amino acid transporter EAAT3 in dopamine neurons. Neuron, 83(2): 404-16. PMCID: PMC4159050.


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