title: Serotonin 5-HT2A and 5-HT6 receptors in the prefrontal cortex of Alzheimer and normal aging patients.
abstract: BACKGROUND
  It has been hypothesized that alterations of the serotonergic system contribute to neuropsychiatric symptoms in Alzheimer disease (AD). Cellular expressions of the two serotonergic receptors 5-HT2A and 5-HT6 have therefore been determined by immunohistochemistry in the prefrontal cortex of patients with AD (n=6) and normal age-matched controls (n = 7).
  
  
  RESULTS
  In normal aging patients, 5-HT2A label was mainly observed in large pyramidal cells, but to a lesser extent also in small pyramidal cells and in stellate cells of cortical layers II-VI. In AD, a similar distribution was observed, but density of positive cells was significantly reduced by 33%. In aging control patients, the 5-HT6 receptor was expressed by pyramidal cells and occasional stellate cells, not only of layers II-V, but also of layer I, where a distinct label was observed in neurons and surrounding fibers. 5-HT6 receptor expression in AD patients had the same pattern, but was significantly decreased by 40%.
  
  
  CONCLUSIONS
  Our results indicate that a decline in neurons expressing 5-HT2A, but also 5-HT6 receptors may play a role in the etiopathology of neuropsychiatric symptoms in AD.
authors.affiliation: Department of Anatomy, Faculty of Medicine and Health Sciences, UAE University, Box 17666, Al Ain, United Arab Emirates. lorke@uaeu.ac.ae
authors.forename: Dietrich E
authors.initials: DE
authors.lastname: Lorke
authors.forename: Gang
authors.initials: G
authors.lastname: Lu
authors.forename: Eric
authors.initials: E
authors.lastname: Cho
authors.forename: David T
authors.initials: DT
authors.lastname: Yew
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000378:metabolism / Q000473:pathology*; D000704:Analysis of Variance; D016022:Case-Control Studies; D002452:Cell Count / Q000379:methods; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D017397:Prefrontal Cortex / Q000378:metabolism*; D017966:Pyramidal Cells / Q000378:metabolism; D011985:Receptors, Serotonin / Q000378:metabolism*
chemical_list: D011985:Receptors, Serotonin; C078730:serotonin 5 receptor; C097216:serotonin 6 receptor