Serotonin 5-HT2 receptors in schizophrenic patients studied by positron emission tomography

5-HT2A receptor density is decreased in the at-risk mental state

“…By focusing on a sample of never-medicated individuals at ultra-high-risk for schizophrenia, the present study avoids such confounds. Our findings obtained with [ 18 F]altanserin complement evidence of reduced [ 18 F]setoperone binding in the prefrontal cortex of drug-naïve patients at onset of schizophrenia (Ngan et al 2000), but conflict with reports of unchanged [ 18 F]setoperone and [ 18 F]spiperone binding in mixed samples of drug-free and drug-naïve schizophrenic patients (Lewis et al 1999;Okubo et al 2000;Trichard et al 1998;Verhoeff et al 2000). However, as compared to the combined 5-HT 2A R/DA D 2 R ligands [ 18 F]setoperone and [ 18 F]spiperone, [ 18 F]altanserin shows a higher selectivity for 5-HT 2A R and is sensitive towards even subtle reductions of 5-HT 2A R density in subcortical areas rich in DA D 2 Rs.…”

“…In addition, the majority of postmortem autoradiography studies have shown reduced 5-HT 2A R binding in the prefrontal cortex of schizophrenic patients (Dean 2003;Matsumoto et al 2005). However, to date, no consensus has evolved on the 5-HT 2A R in vivo status in schizophrenia (Lewis et al 1999;Ngan et al 2000;Okubo et al 2000;Trichard et al 1998;Verhoeff et al 2000).…”

Occupancy of dopamine D1, D2 and serotonin2A receptors in schizophrenic patients treated with flupentixol in comparison with risperidone and haloperidol

“…This is usually ignored because several SPECT/PET studies failed to detect significant baseline differences, in spite of altered dopaminergic transmission (Abi-Dargham et al 1998). No baseline differences were found with NMS and SCH either (Okubo et al 2000;Karlsson et al 2002), however, one has to keep in mind that such a baseline shift may induce a rather small error for high levels of occcupancy, but not for lower levels (at 80% true occupancy, a hypothetical upregulation by 25% would result in an apparent occupancy of 75%; at 40% true occupancy, the same baseline shift would result in 25% apparent occupancy). Furthermore, the fact that no significant baseline differences were observed after a certain drug-free interval does not generally exclude an altered baseline status under neuroleptic treatment, especially since different neuroleptics may interact differently with the receptor (Weiner et al 2001;Gründer et al 2003).…”

A positron emission tomography (PET) study of cerebral dopamine D2 and serotonine 5-HT2A receptor occupancy in patients treated with cyamemazine (Tercian)

“…Consequently, the question of a possible confounding effect of diagnosis on receptor binding needs to be addressed. Overall, previous in vivo PET and SPECT studies suggest that baseline differences in striatal D 2 and neocortical 5-HT 2 receptor densities between psychotic patients and healthy subjects are negligible as compared to the large effects caused by antipsychotic medications (Farde et al 1990;Hietala et al 1994;Nordström et al 1995;Sedvall et al 1995 for review;Bigliani and Pilowsky 1999 for review;Okubo et al 2000;Yang et al 2004). The possibility of an alteration of D 2 or 5-HT 2 receptor densities in the two patients with anxiety disorders remains; however, we observed a good agreement between measured RO and RO predicted by the saturation curve across all subjects (r 2 >0.9).…”