Description:

The department of Physiology welcomes Julie Kauer, PhD., Professor in the department of Molecular Pharmacology, Physiology, and Biotechnology at Brown University.

Our work in the ventral tegmental area (VTA) focuses on inhibitory GABAergic synapses and their modulation by stress and drugs of abuse. We were the first to identify a form of long-term potentiation at these synapses, and have characterized the molecular mechanisms underlying the LTP. The VTA is essential for the development of addiction to drugs of abuse and contributes to relapse. We find that a single morphine treatment entirely blocks LTP at GABAergic synapses. This work defines a novel mechanism by which morphine can modulate the firing of dopamine neurons in the VTA known to be required for addiction. Other drugs of abuse including nicotine, cocaine, and ethanol also attenuate or block LTP at these GABAergic synapses. We also discovered that a brief stressful experience also entirely blocks this form of LTP. Intriguingly, we have found that kappa opioid receptors become persistently active after acute stress, for a period lasting at least five days. We have linked this observation to stress-induced relapse to cocaine-seeking in rats; blocking kappa opioid receptors even days after the initial stress insult prevents relapse. We are currently exploring the mechanisms by which stress triggers this neurobiological adaptation. We are also using optogenetic and cell-marking tools to delineate the VTA circuits responsive to opioid drugs and to acute stressors.