| |
Morphine inhibits
pain, in part, by activating a naturally occurring pain modulatory
system that runs from the periaqueductal gray (PAG) to rostral
ventromedial medulla (RVM) to spinal cord. Microinjection of
morphine into any of these structures inhibits pain. We have shown
that repeated administration of morphine produces tolerance because
of adaptations in the ventrolateral part of the PAG. Subsequent
studies revealed that this change occurs in opioid-sensitive
GABAergic neurons in the PAG. Currently, we are using
pharmacological and electrophysiological techniques to determine the
specific neural adaptation underlying tolerance in these neurons.
This work is supported by the National Institute on Drug Abuse.
For more information on Dr.
Morgan's research, see:
http://www.vancouver.wsu.edu/fac/morgan/morgan_home.html
Biographical Information
Michael Morgan was
an undergraduate and graduate student at the University,
California at Los Angeles (UCLA) earning a B.A. (1984), M.A.
(1985), and Ph.D. (1989) degree in Psychology (Physiological
Psychology emphasis). He continued his education in the Department
of Neurology at the
University of California, San Francisco as a postdoctoral fellow from
1989 to 1993. Dr. Morgan has been in the Department of Psychology at
Washington State University Vancouver since 1993. He is the only
member of the Vancouver faculty to
receive the Student’s Award for Teaching Excellence and the
Chancellor’s Award for Research Excellence.
Recent Publications
Ingram, S.L., Fossum, E.N., & Morgan,
M.M. (2006). Behavioral and electrophysiological evidence for opioid
tolerance in adolescent rats. Neuropsychopharmacology.
Morgan, M. M.,
Fossum, E. N., Stalding, B. M., & King, M. M. (2006). Morphine
antinociceptive potency on chemical, mechanical, and thermal
nociceptive tests in the rat. J. Pain, 7:358-366.
Morgan, M. M., Tierney, B. W., & Ingram, S. L. (2005). Intermittent
dosing prolongs tolerance to the antinociceptive effect of morphine
microinjection into the periaqueductal gray. Brain Research,
1059:173-178.
Lane, D. A., Patel,
P. A., & Morgan, M. M. (2005). Evidence for an intrinsic mechanism
of antinociceptive tolerance within the ventrolateral Periaqueductal
Gray of rats. Neuroscience, 135:227-234.
Lane, D. A. &
Morgan, M. M. (2005). Antinociceptive tolerance to morphine from
repeated nociceptive testing in the rat. Brain Research, 1047:65-71.
Morgan, M. M., Clayton, C. C., & Boyer-Quick. J. S., &. (2005).
Differential susceptibility of the PAG and RVM to tolerance to the
antinociceptive effect of morphine in the rat. Pain, 113:91-98.
Return to Faculty List
VCAPP Home
|
|
