Dr. Michael Morgan

Professor of Psychology
Phone: (360) 546-9726
Fax: (360) 546-9038
Located in Classroom (VCLS) 208G
Office Hours: Tuesday 12:15 - 1:15
Support Staff: Janet DeWitt

Student evaluations of Courses I have Taught:


Course ID Title Meeting Time Location Semester Syllabus
Psych 312 Experimental Methods in Psychology Tu,Th 2:50-5:30 VUCB 222 Fall 2011
Psych 401 Historical Development of Psychology Tu,Th 12:00 - 1:15 VUCB 222 Fall 2011
Psych 372 Biological Basis of Behavior Tu,Th 4:15-5:30 VUCB 225 Spring 2012


 Neural Mechanisms of Morphine Tolerance

Opiates such as morphine are the most effective treatment for pain. Unfortunately, the ability of opioids to relieve pain is reduced with repeated administration. The primary goal of our research is to determine the mechanism for tolerance so long lasting and effective pain treatments can be developed. Our research has shown that tolerance occurs by a change in opioid sensitive GABAergic neurons in the ventrolateral region of the periaqueductal gray (PAG). Injection of opioids into this brain region produces analgesia and repeated injections results in tolerance. We are currently examining the role of mu-opioid receptor internalization in morphine tolerance. These studies indicate that repeated administration of morphine increases the likelihood that the mu-opioid receptor will internalize which produces tolerance by limiting membrane signaling.

Current Funding:

Morgan, M. M., Aicher, S.A. (co-P.I), & Ingram, S. L. (co-P.I). National Institute on Drug Abuse. Psychostimulants Induce Long-Term Changes in Nociception (R01 DA027625). September 2009 to July 2014. $1,625,000 direct costs.

Morgan, M. M. & Ingram, S. L. (co-P.I) National Institute on Drug Abuse. Cellular mechanisms of opioid tolerance. (RO1 DA015498-06). August 2009 to July 2011. $450,000 direct costs.

Morgan, M. M.  National Institute on Drug Abuse. Neural Mechanisms of Enhanced Cannabinoid/Opioid Antinociception. (R03 DA026591). May, 2009 to April, 2011. $100,000 direct costs.

Graduate Students

Erin Bobeck, Psychology

Melissa Mehalick, Psychology

Kimber Saville, Psychology

Michelle Cyr, Psychology, Ph.D. 2011

Adie Wilson, Neuroscience, Ph.D. 2011

Diane Lane, Psychology, Ph.D. 2004

Recent Publications

Wilson-Poe, A.R., Morgan, M.M., Aicher, S.A., & Hegarty, D.M. (in press). Distribution of CB1 Cannabinoid Receptors and Their Relationship with Mu-Opioid Receptors in the Rat Periaqueductal Gray. Neuroscience.

Cyr, M.C., Ingram, S.L., Aicher, S.A., Morgan, M.M. (2012). Chronic psychostimulant exposure to adult, but not periadolescent rats reduces subsequent morphine antinociception. Pharmacology, Biochemistry, and Behavior, 101:538-543. PMID: 22405777

Cornélio, A.M., Nunes-de-Souza, R.L. & Morgan, M.M. (2012) Contribution of the rostral ventromedial medulla to post-anxiety induced hyperalgesia. Brain Research, 1450:80-86. PMID: 22418057

Morgan, M. M. & Christie, M. J. (2011) Analysis of Opioid Efficacy, Tolerance, Addiction, and Dependence from Cell Culture to Human. British Journal of Pharmacology, 164, 1322–1334. PMID: 21434879

Cornélio, A.M., Mendes-Gomes, J., Fugimoto, J.S., Morgan, M.M., & Nunes-de-Souza, R.L. (2011) Environmentally induced antinociception and hyperalgesia in rats and mice. Brain Research, 1415:56-62. PMID: 21880302

Gunn, A., Bobeck, E.N., Weber, C., & Morgan, M.M. (2011). The influence of non-nociceptive factors on hot plate latency in rats. Journal of Pain, 12(2):222-227. PMID: 20797920

Fyfe LW, Cleary DR, Macey TA, Morgan MM, Ingram SL. (2010). Tolerance to the antinociceptive effect of morphine in the absence of acute presynaptic desensitization in rat periaqueductal gray neurons. J Pharmacol Exp Ther. 335(3):674-80. PMID: 20739455

Macey T. A., Ingram, S. L., Bobeck, . N., Hegarty, D. M., Aicher, S. A., Arttamangkul, S. & Morgan, M. M. (2010). Opioid receptor internalization contributes to dermorphin-mediated antinociception. Neuroscience, 168:543-50. PMID: 20394808


  • Ph.D. 1989 UCLA Physiological Psychology (J.C. Liebeskind mentor)
  • Post-doctoral fellow 1989 - 1993 Dept. of Neurology, UC, San Francisco (H.L. Fields mentor)