title: Parvalbumin neurons in the entorhinal cortex of subjects diagnosed with bipolar disorder or schizophrenia.
abstract: 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.
authors.affiliation: Translational Neuroscience Laboratory, McLean Hospital, Belmont, Massachusetts 02478, USA.
authors.forename: Harry
authors.initials: H
authors.lastname: Pantazopoulos
authors.forename: Nicholas
authors.initials: N
authors.lastname: Lange
authors.forename: Ross J
authors.initials: RJ
authors.lastname: Baldessarini
authors.forename: Sabina
authors.initials: S
authors.lastname: Berretta
mesh_terms: 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*
chemical_list: D010320:Parvalbumins