The Journal of Neuroscience, July 15, 2000, 20(14):5538-5543
Perinatal Distress Leads to Lateralized Medial Prefrontal
Cortical Dopamine Hypofunction in Adult Rats
Wayne G.
Brake1,
Ron M.
Sullivan2, and
Alain
Gratton2
1 Laboratory of Neuroendocrinology, The Rockefeller
University, New York, New York 10021, and 2 Douglas
Hospital Research Centre, Department of Psychiatry, McGill University,
Montréal, Canada H4H 1R3
Obstetric complications involving anoxia or prolonged hypoxia are
suspected to increase the risk for such mental disorders as
schizophrenia and attention deficit-hyperactivity disorder. In
previous studies, we reported evidence of enhanced nucleus accumbens
(NAcc) dopamine (DA) function in adult rats subjected to intrauterine
anoxia during cesarean (C) section birth. In the present study, we used
voltammetry and monoamine-sensitive electrodes to investigate the
possibility that this functional hyperactivity of the meso-NAcc system
is attributable to a loss of inhibitory control from the medial
prefrontal cortex (PFC). We monitored the DA responses to repeated
once-daily stress in the right or left PFC of adult male rats born
vaginally (VAG) or by C-section, either with (C + 15) or without (C + 0) an additional 15 min of intrauterine anoxia. In C + 15 animals, we
observed a pronounced and persistent blunting of stress-induced DA
release in the right PFC but not in the left; with repeated testing, a
similar pattern of dampened right PFC DA stress responses emerged in C + 0 animals. In addition, C + 15 animals were spontaneously more active
than VAG and C + 0 animals and displayed an increase in PFC DA
transporter density that was also lateralized to the right hemisphere.
There was no evidence, however, that PFC D1 and
D2 receptor levels differed between birth groups or
hemisphere. These findings suggest a mechanism by which perinatal
complications involving anoxia might contribute to the etiology of
mental disorders that have been linked to disturbances in central DA
transmission and lateralized PFC dysfunction.
Key words:
stress; voltammetry; cesarean section; anoxia; obstetric
complications; dopamine transporter; asymmetry; attention
deficit/hyperactivity disorder
Copyright © 2000 Society for Neuroscience 0270-6474/00/20145538-06$05.00/0