Graduate Studies Faculty
Tamara J. Phillips, Ph.D.
Neuroscience Graduate Program
Research Interests:Behavioral genetics, Quantitative genetics, Alcohol, Methamphetamine, Addiction, Neuroscience » Click here for more about Dr. Phillips's research » PubMed Listing
Preceptor RotationsAcademic Term Available Winter 2014 Maybe Spring 2014 Maybe Fall 2015 Maybe Summer 2015 Maybe Fall 2014 Maybe
Faculty MentorshipDr. Phillips might be available as a mentor for 2013-2014. Dr. Phillips might be available as a mentor for 2014-2015.
Summary of Current Research
The broad area of interest in my laboratory is the genetic dissection of behavioral traits associated with risk for the development of alcoholism and drug abuse. We utilize genetic animal models to study acute and chronic drug and alcohol effects associated with drug reward, behavioral sensitivity, and neuroadaptation. We also examine traits that co-segregate with addiction. Mice genetically prone and resistant to the behavioral effects of abused drugs are used in pharmacological, genetic mapping, and gene expression studies to identify specific genetically-determined mechanisms that produce variations in addiction-related behavior. We are currently focusing most of our attention on two drugs, alcohol and methamphetamine, due to my involvement with both the Portland Alcohol Research Center (PARC) and Methamphetamine Abuse Research Center (MARC).
A primary interest is the mechanisms of behavioral sensitization (i.e., the increase in the effect of a drug with repeated exposures). The neuroadaptations associated with behavioral sensitization have been proposed to be determinant factors in the development of drug addiction; they may be associated with the transition from casual use to excessive use and addiction. The genetic studies in my lab have the potential for identifying common and unique genetic and neurochemical mechanisms underlying the motivational and neuroadaptive effects of addictive drugs. Genetic models we use include selectively bred mouse lines, panels of inbred strains, transgenic mice, knockout mice, recombinant inbred strains, and congenic strains. Some of our most exciting results are from studies that have focused on the peptide, corticotropin releasing factor (CRF).
Pharmacological and molecular genetic approaches are utilized in my lab. For example, we used mice stereotactically implanted with indwelling cannulae to infuse drugs into specific brain regions or inactivate specific brain regions. For example, we have found that inactivation of the lateral septum reduces alcohol drinking, that then recovers when the effects of temporary inactivation wear off. We are now examining changes in brain circuitry that occur with lateral septum inactivation that may have a role in the reduced alcohol consumption.
My lab is also very interested in the co-abuse of alcohol and nicotine and the role that nicotinic receptors and genes play in some alcohol effects. It is possible that these drugs are co-abused because there is a common underlying genetic mechanism in risk for addiction to the two drugs, because use of one drug with the other creates a stronger rewarding experience, or because one drug reduces some of the negative consequences of the other.These are hypotheses that we are exploring.
Finally, our primary research goal involving methamphetamine is to determine what genetic mechanisms impact risk for continued use of methamphetamine. To accomplish this, we are using selective breeding methods in combination with gene mapping and microarray gene expression analyses. We have completed the selective breeding of lines of mice that drink high and low amounts of methamphetamine and have found that the high line, compared to the low drinking line, shows increased sensitivity to the rewarding effects of methamphetamine, will work harder to gain access to a drinking tube that contains methamphetamine, and shows little sensitivity to aversive effects of methamphetamine. We have also found that neuroimmune pathways play a significant role in the differences between these high and low methamphetamine drinking lines. We are continuing to study these mechanisms as well as following up on gene mapping and behavioral results suggesting a role for opioid pathways, on examining neurotransmitter transporters that play a significant role in methamphetamine effects. We are also collaborating with other investigators to develop novel pharmacotherapeutic agents for the treatment of methamphetamine addiction.
Gubner, N.R., Reed, C., McKinnon, C.S. and Phillips, T.J. (2013) Unique genetic factors influence sensitivity to the rewarding and aversive effects of methamphetamine versus cocaine. Behav Brain Res 256:420-427.
Harkness, J.H., Hitzemann, R.J., Edmunds, S. and Phillips, T.J. (2013) Effects of sodium butyrate on methamphetamine-sensitized locomotor activity. Behav Brain Res 239:139-147. PMCID: PMC3546510
Shabani, S., McKinnon, C.S., Cunningham, C.L. and Phillips, T.J. (2012) Profound reduction in sensitivity to the aversive effects of methamphetamine in mice bred for high methamphetamine intake. Neuropharmacology 62:1134-1141. PMCID: PMC3297479
Shabani, S., Dobbs, L.K., Ford, M.M., Finn, D.A. and Phillips, T.J. (2012) A genetic animal model of differential sensitivity to methamphetamine reinforcement. Neuropharmacology 62:2168-2176. PMCID: PMC3320769
B.A. (1981) William Paterson College
Ph.D. (1986) State University of New York, Albany
Postdoctoral Research Associate, Rutgers University
Assistant Professor, Department of Medical Psychology, OHSU
Associate Professor, Department of Behavioral Neuroscience, OHSU