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-HT 2A and 5-HT 6 have therefore been determined by immunohistochemistry in the prefrontal cortex of patients with AD (n=6) and normal age-matched controls (n = 7).

Amyloid-β oligomers link depressive-like behavior and cognitive deficits in mice

“…The latter possibility is in line with the observation that pro-inflammatory cytokines impact serotonin metabolism 7, 8 and that increased serotonin levels are associated with lower brain Aβ levels in transgenic mouse models of AD and in humans. 9 Moreover, 5-HT1A and 5-HT2A receptors have been reported to be reduced in post-mortem AD brain, 10 and 5-HT1A receptors have been found to be reduced in vivo in AD. 11 Brain disturbances that place a person at risk for developing depression and AD are still largely unknown.…”

Distribution of serotonin receptor 5-HT6 mRNA in rat neuronal subpopulations: A double in situ hybridization study

“…This 68 suggests that the 5-HT 6 R is not a pre-synaptic autorecep- gesting that the 5-HT 6 R is not located on cholinergic pro-75 jection neurons either (Marcos et al, 2006). A few studies 76 colocalizing the 5-HT 6 R protein with neuronal markers by 77 means of immunohistochemistry have reported 5-HT 6 R 78 localization at the cellular level in both pyramidal cells 79 and GABAergic interneurons (Woolley et al, 2004;80 Lorke et al, 2006;Marazziti et al, 2013). These findings 81 remain to be confirmed, however, as immunohistochem-82 istry has so far been hampered by the lack of commer-83 cially available specific antibodies.…”

Development of the human insular cortex: differentiation, proliferation, cell death, and appearance of 5HT-2A receptors

“…5HT-2A receptor was one of the 14 distinct mammalian 5HT receptor subtypes and one which was supposed to be associated with behavioral alternation and emotion (Lanctôt et al 2001;Barnes and Sharp 1999;Aghajanian and Marek 2000;Williams et al 2002). Presence of 5HT-2A receptors had been reported in the human prefrontal cortex (Lorke et al 2006) and were present here in the insula in the late term of gestation. The quantity of these positive cells was, however, much lower than those of the opercula (especially the temporal operculum) covering the insula.…”