Parvalbumin neurons in the entorhinal cortex of subjects diagnosed with bipolar disorder or schizophrenia.
BACKGROUND
Growing evidence indicates that the entorhinal cortex (ECx) might be affected in schizophrenia (SZ) and bipolar disorder (BD). To test whether distinct interneuronal subpopulations might be altered, numbers of parvalbumin-immunoreactive (PVB-IR) neurons were measured in the ECx of BD and SZ subjects. These neurons play a pivotal role within ECx intrinsic circuits.


METHODS
Numbers, numerical density, and soma size of PVB-IR neurons were measured in the ECx of normal control (n = 16), BD (n = 10), and SZ (n = 10) subjects. The volume of the ECx was measured in Nissl-stained sections.


RESULTS
In BD, decreases of total numbers (p = .02) and numerical densities (p = .01) of PVB-IR neurons were detected in the ECx. Within distinct subregions, reductions were detected in the superficial layers of the lateral (p = .02), intermediate (p = .04), and caudal (p = .01) ECx. In SZ, total numbers and numerical densities were not altered. A reduction of soma size was present in the intermediate ECx (p = .01). Volume was unaffected in either disorder.


CONCLUSIONS
In BD, a decrease of PVB-IR neurons may alter intrinsic inhibitory networks within the superficial layers of the ECx. The likely consequence is a disruption of integration and transfer of information from the cerebral cortex to the hippocampus.
Pantazopoulos
Harry
H
Translational Neuroscience Laboratory, McLean Hospital, Belmont, Massachusetts 02478, USA.
Lange
Nicholas
N
Baldessarini
Ross J
RJ
Berretta
Sabina
S
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001714:Bipolar Disorder / Q000473:pathology*; D002452:Cell Count; D018728:Entorhinal Cortex / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D008875:Middle Aged; D009474:Neurons / Q000378:metabolism*; D010320:Parvalbumins / Q000378:metabolism*; D011180:Postmortem Changes; D012559:Schizophrenia / Q000473:pathology*
D010320:Parvalbumins