Question: Which receptors can be evaluated with the [18F]altanserin?

Context:
PURPOSE: While the selective 5-hydroxytryptamine type 2a receptor (5-HT2AR) radiotracer [18F]altanserin is well established in humans, the present study evaluated its suitability for quantifying cerebral 5-HT2ARs with positron emission tomography (PET) in albino rats.
CONCLUSION: [18F]Altanserin PET is a reliable tool for in vivo quantification of 5-HT2AR availability in albino rats.
Imaging the cerebral serotonin 2A (5-HT2A ) receptors with positron emission tomography (PET) has been carried out in humans with [(11) C]MDL 100907 and [(18) F]altanserin.
The cortical binding of [(18) F]MH.MZ and [(18) F]altanserin was blocked by ketanserin supporting that both radioligands bind to 5-HT2A receptors in the pig brain.
We investigated 94 healthy individuals (60 men, mean age 47.0±18.7, range 23-86) to determine if trait aggression and trait impulsivity were related to frontal cortex 5-HT2A receptor binding (5-HT2AR) as measured with [18F]-altanserin PET imaging. 
Two hours after placebo/drug administration, 250 MBq of the 5-HT(2A) receptor selective PET-radiotracer [(18)F]altanserin was administered intravenously as a 30s bolus.
These data suggest that the combination of a dexfenfluramine-induced 5-HT release and subsequent assessment of 5-HT(2A) receptor availability with [(18)F]altanserin PET is suitable to measure cortical 5-HT release capacity in the human brain.
The 5-hydroxytryptamine type 2a (5-HT(2A)) selective radiotracer [(18)F]altanserin has been subjected to a quantitative micro-positron emission tomography study in Lister Hooded rats.
[(18)F]altanserin is suitable for quantification of 5-HT(2A) receptor availability in rats.
Altanserin, a fluorobenzoyl derivative related to ketanserin, was reported to be a potent antagonist of 5-HT2A receptors with >100-fold selectivity over D2/3 receptors, 5-HT1A, 5-HT6, and 5-HT7 (9, 10). This led to the development of 3-{2-[4-(4-[(18)F]fluorobenzoyl)-1-piperidyl]ethyl}-2-sulfanyl-3H-quinazolin-4-one ([(18)F]altanserin) as a useful tool for 5-HT2A receptor PET imaging in vivo (11). 
Altanserin, a fluorobenzoyl derivative related to ketanserin, was reported to be a potent antagonist of 5-HT2A receptors with >100-fold selectivity over D2/3 receptors, 5-HT1A, 5-HT6, and 5-HT7 (9, 10). This led to the development of 3-{2-[4-(4-[(18)F]fluorobenzoyl)-1-piperidyl]ethyl}-2-sulfanyl-3H-quinazolin-4-one ([(18)F]altanserin) as a useful tool for 5-HT2A receptor PET imaging in vivo (11). 5-HT2A antagonists bind to the total pool of receptors, whereas 5-HT2A agonists bind only to the high-affinity functional state of the receptor but may be more important in disease states because the high affinity sites are the ones that transmit the intracellular signals. 
Baseline and follow-up partial volume corrected levels of 5-HT2A in four neocortical lobes and the posterior cingulate gyrus were investigated using [18F]altanserin positron emission tomography with a bolus-infusion approach.
Altanserin, a fluorobenzoyl derivative related to ketanserin, was reported to be a potent inhibitor of 5-HT2A receptors with >100-fold selectivity over D2/3 receptors, 5-HT1A, 5-HT6, and 5-HT7 (8, 9). This led to the development of 3-[2-[4-(4-[(18)F]fluorobenzoyl)-1-piperidyl]ethyl]-2-sulfanyl-3H-quinazolin-4-one ([(18)F]altanserin) as a useful tool for 5-HT2A receptor PET imaging in vivo (10).
We investigated the relationships of gender, mood, impulsivity, aggression and temperament to 5HT(2A) receptor binding in 21 healthy subjects using [18F]altanserin and PET neuroimaging.
We, therefore, studied the binding potential of the serotonin 2A (5-HT(2A)) receptor ligand [18F]altanserin in 8 patients with clinically probable PSP and 13 healthy controls using positron emission tomography. 
[(18)F]altanserin is the preferred radiotracer for in-vivo labeling of serotonin 2A receptors by positron emission tomography (PET). 
Twenty-one healthy subjects underwent PET scanning with the 5-HT(2A) antagonist, [(18)F]altanserin.
METHODS: [(18)F]-Altanserin PET was used to quantify 5-HT(2A) receptors in 12 healthy elderly individuals at baseline and at 2 years in six volumes of interest. 
The aim of this feasibility study was to examine whether acute ketamine-induced 5-HT release interferes with the binding of the 5-HT(2A) receptor (5-HT(2A)R) radioligand [(18)F]altanserin and positron emission tomography (PET)
METHODS: Fifteen women ill with AN (ILL AN) were compared with 29 healthy control women (CW); PET and [11C]WAY100635 were used to assess binding potential (BP) of the 5-HT1A receptor, and [18F]altanserin was used to assess postsynaptic 5-HT2A receptor BP.
In summary, these results demonstrate that the test-retest variability of [18F]altanserin-specific binding is comparable to that of other PET radiotracers and that the regional specific binding of [18F]altanserin in human brain was correlated with the known regional distribution of 5-HT2A receptors.
[18F]altanserin binding to human 5HT2A receptors is unaltered after citalopram and pindolol challenge.
Our data confirmed that [18F]altanserin is a valid tracer for 5HT2 receptors binding studies.
PET quantification of 5-HT2A receptors in the human brain: a constant infusion paradigm with [18F]altanserin.
In vivo binding of [18F]altanserin to rat brain 5HT2 receptors: a film and electronic autoradiographic study.
We used [18F]altanserin and positron emission tomography (PET) to image serotonin 5-HT2A receptors in humans.
Quantification of 5-HT2A receptors in the human brain using [18F]altanserin-PET and the bolus/infusion approach.
These findings support the usefulness of [18F]altanserin as a radioligand for PET studies of 5-HT2A receptors.
This study was performed to identify and characterize the radiometabolites of the serotonin 5-HT2A receptor ligand [18F]altanserin in supporting quantification of the target receptors by positron emission tomography.
PURPOSE: To determine the reproducibility of measurements of brain 5-HT2A receptors with an [18F]altanserin PET bolus/infusion approach.
18F]altanserin binding to human 5HT2A receptors is unaltered after citalopram and pindolol challenge.
Influence of synaptic serotonin level on [18F]altanserin binding to 5HT2 receptors in man.
The aim of the present study is to describe and validate a method for accurate quantification of 5-hydroxytryptamine (5-HT)(2A) receptors using [18F]altanserin-positron emission tomography (PET) and the bolus/infusion approach.
The regional [18F]altanserin DV values using both of these methods were significantly correlated with literature-based values of the regional concentrations of 5-HT2A receptors determined by postmortem autoradiographic studies (r2 = 0.95, P < 0.001 for the 4C model and r2 = 0.96, P < 0.001 for the Logan method).
In summary, these results demonstrate that the test-retest variability of [18F]altanserin-specific binding is comparable to that of other PET radiotracers and that the regional specific binding of [18F]altanserin in human brain was correlated with the known regional distribution of 5-HT2A receptors.
These findings support the usefulness of [18F]altanserin as a radioligand for PET studies of 5-HT2A receptors.
Reduced binding of [18F]altanserin to serotonin type 2A receptors in aging: persistence of effect after partial volume correction.
Visualisation of loss of 5-HT2A receptors with age in healthy volunteers using [18F]altanserin and positron emission tomographic imaging.
Imaging the cerebral serotonin 2A (5-HT2A ) receptors with positron emission tomography (PET) has been carried out in humans with [(11) C]MDL 100907 and [(18) F]altanserin
[(18)F]altanserin showed sufficient brain uptake in a distribution pattern consistent with the known distribution of 5-HT(2A) receptors
This controlled cross-over PET study aimed to identify brain regions with WM-induced changes in the binding potential (BP(nd)) of the 5-HT2aR antagonist [(18)F]altanserin
MZ and [(18) F]altanserin was blocked by ketanserin supporting that both radioligands bind to 5-HT2A receptors in the pig brain
PET was performed by using [18F]altanserin to evaluate 5-HT2A receptor binding in 11 elderly patients with depression (four men, seven women; mean age = 65.0 years, SD = 5.5); nine Alzheimer's disease patients, including three with concurrent depression (two men, seven women; mean age = 69.7 years, SD = 5.0); and 10 age-matched healthy subjects (four men, six women; mean age = 69.8 years, SD = 5.0)
While the selective 5-hydroxytryptamine type 2a receptor (5-HT2AR) radiotracer [18F]altanserin is well established in humans, the present study evaluated its suitability for quantifying cerebral 5-HT2ARs with positron emission tomography (PET) in albino rats.
This study was performed to identify and characterize the radiometabolites of the serotonin 5-HT2A receptor ligand [18F]altanserin in supporting quantification of the target receptors by positron emission tomography
To this end, the regional distribution and intrasubject test-retest variability of the binding of [18F]altanserin were measured as important steps in the further development of [18F]altanserin as a radiotracer for positron emission tomography (PET) studies of the serotonin 5-HT2A receptor
Our data confirmed that [18F]altanserin is a valid tracer for 5HT2 receptors binding studies.
In summary, these results demonstrate that the test-retest variability of [18F]altanserin-specific binding is comparable to that of other PET radiotracers and that the regional specific binding of [18F]altanserin in human brain was correlated with the known regional distribution of 5-HT2A receptors
Characterization of radioactive metabolites of 5-HT2A receptor PET ligand [18F]altanserin in human and rodent.
We used [18F]altanserin and positron emission tomography (PET) to image serotonin 5-HT2A receptors in humans

Answer: 5-HT2A (5-hydroxytryptamine type 2a) receptor can be evaluated with the [18F]altanserin.
Exact answer: 5-HT2A