Lamina-specific alterations in the dopamine innervation of the prefrontal cortex in schizophrenic subjects.
OBJECTIVE
Abnormalities in dopamine neurotransmission in the prefrontal cortex have been implicated in the pathophysiology of schizophrenia. However, the integrity of the dopamine projections to the prefrontal cortex in this disorder has not been directly examined.


METHODS
The authors employed immunocytochemical methods and antibodies against tyrosine hydroxylase, the rate-limiting enzyme in dopamine biosynthesis, and the dopamine membrane transporter to examine dopamine axons in the dorsomedial prefrontal cortex (area 9) from 16 pairs of schizophrenic and matched control subjects.


RESULTS
Compared to the control subjects, the total length of tyrosine hydroxylase-immunoreactive axons was unchanged in the superficial and middle layers of the schizophrenic subjects but was reduced by an average of 33.6% in layer 6. The total length of tyrosine hydroxylase-positive axons in layer 6 was decreased in 13 of the schizophrenic subjects compared to their control subjects. Axons immunoreactive for the dopamine membrane transporter showed a similar pattern of change. In contrast, axons labeled for the serotonin transporter did not differ between schizophrenic and control subjects in any layer examined. In addition, the density of tyrosine hydroxylase-containing axons did not differ between monkeys chronically treated with haloperidol and matched control animals.


CONCLUSIONS
These findings reveal that schizophrenia is associated with an altered dopamine innervation of prefrontal cortex area 9 that is lamina- and neurotransmitter-specific and that does not appear to be a consequence of pharmacological treatment. Together, these data provide direct evidence for a disturbance in dopamine neurotransmission in the prefrontal cortex of schizophrenic subjects.
Akil
M
M
Department of Psychiatry, University of Pittsburgh, PA 15213, USA.
Pierri
J N
JN
Whitehead
R E
RE
Edgar
C L
CL
Mohila
C
C
Sampson
A R
AR
Lewis
D A
DA
D000328:Adult; D000368:Aged; D000818:Animals; D001369:Axons / Q000201:enzymology / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D003692:Delayed-Action Preparations; D004298:Dopamine / Q000276:immunology / Q000378:metabolism / Q000502:physiology*; D050483:Dopamine Plasma Membrane Transport Proteins; D005260:Female; D006220:Haloperidol / Q000494:pharmacology; D006801:Humans; D007150:Immunohistochemistry; D008252:Macaca fascicularis; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism; D026901:Membrane Transport Proteins; D008875:Middle Aged; D009419:Nerve Tissue Proteins; D017397:Prefrontal Cortex / Q000201:enzymology / Q000378:metabolism / Q000503:physiopathology*; D012559:Schizophrenia / Q000378:metabolism / Q000503:physiopathology*; D050486:Serotonin Plasma Membrane Transport Proteins; D009435:Synaptic Transmission / Q000502:physiology*; D014446:Tyrosine 3-Monooxygenase / Q000276:immunology / Q000378:metabolism
D002352:Carrier Proteins; D003692:Delayed-Action Preparations; D050483:Dopamine Plasma Membrane Transport Proteins; D008562:Membrane Glycoproteins; D026901:Membrane Transport Proteins; D009419:Nerve Tissue Proteins; C493230:SLC6A4 protein, human; D050486:Serotonin Plasma Membrane Transport Proteins; D014446:Tyrosine 3-Monooxygenase; D006220:Haloperidol; D004298:Dopamine