The Journal of Neuroscience, December 15, 1998, 18(24):10700-10708
Differential Regulation of Neurotrophin and trk
Receptor mRNAs in Catecholaminergic Nuclei during Chronic Opiate
Treatment and Withdrawal
Suzanne
Numan1,
Sarah
B.
Lane-Ladd1, 2,
Lixin
Zhang4,
Kerstin H.
Lundgren4,
David S.
Russell1, 3,
Kim B.
Seroogy4, and
Eric J.
Nestler1, 2
Laboratory of Molecular Psychiatry, Departments of
1 Psychiatry, 2 Neurobiology, and
3 Neurology, Yale University School of Medicine and
Connecticut Mental Health Center, New Haven, Connecticut 06508, and
4 Department of Anatomy and Neurobiology, University of
Kentucky College of Medicine, Lexington, Kentucky 40536
The neurotrophins brain-derived neurotrophic factor (BDNF) and
neurotrophin-3 (NT-3) and their receptors trkB and
trkC, respectively, are expressed in the locus coeruleus
(LC) and ventral tegmental area (VTA), brain regions known to be
involved in opiate addiction. Previously, administration of exogenous
neurotrophins has been shown to oppose effects of chronic morphine
treatment on LC and VTA neurons. However, the response of endogenous
neurotrophins in LC and VTA to opiate treatment is unknown. In this
study, BDNF, NT-3, trkB, and trkC mRNAs
were analyzed in these regions after chronic morphine treatment and
during antagonist precipitated withdrawal. Although chronic morphine
exposure resulted in only modest increases in BDNF and NT-3 mRNA
expression in LC, precipitated withdrawal led to a marked, rapid, and
prolonged increase in BDNF mRNA and a delayed decrease in NT-3 mRNA.
Levels of trkB and trkC mRNAs, which were
unchanged by chronic morphine treatment, were elevated in LC at 2 and 6 hr of withdrawal. By 20 hr, trkB mRNA levels in LC had
returned to control, whereas trkC mRNA levels fell below
control values. In contrast to the substantial alterations observed in
LC, there was no regulation of the neurotrophins or trk
mRNAs within the VTA during chronic opiate treatment or withdrawal, with the exception of an increase in trkB mRNA at 6 hr
of withdrawal. These results suggest that neurotrophins and their
receptors per se may be involved in opiate-induced plasticity of the
LC, whereas other mechanisms would appear to be involved in the VTA.
Key words:
locus coeruleus; ventral tegmental area; opiates; neurotrophins; neural plasticity; morphine
Copyright © 1998 Society for Neuroscience 0270-6474/98/182410700-09$05.00/0