5-I-R91150
Encyclopedia
5-I-R91150 is a compound that acts as a potent and selective antagonist of 5-HT2A receptors
. Its main application is as its iodine-123
radiolabeled
form, in which it can be used in SPECT scanning in human neuroimaging
studies, to examine the distribution of the 5-HT2A receptor subtype in the brain
, e.g. with respect to sex
and age
and in adults with Asperger syndrome
or Alzheimer's disease
.
An alternative 5-HT2A receptor ligand also used in neuroimaging is altanserin
.
5-HT2A receptor
The mammalian 5-HT2A receptor is a subtype of the 5-HT2 receptor that belongs to the serotonin receptor family and is a G protein-coupled receptor . This is the main excitatory receptor subtype among the GPCRs for serotonin , although 5-HT2A may also have an inhibitory effect on certain areas such...
. Its main application is as its iodine-123
Iodine-123
Iodine-123 is a radioactive isotope of iodine used in nuclear medicine imaging, including single photon emission computed tomography . The isotope's half-life is 13.22 hours; the decay by electron capture to tellurium-123 emits gamma radiation with predominant energies of 159 keV and 127 keV...
radiolabeled
Isotopic labeling
Isotopic labeling is a technique for tracking the passage of a sample of substance through a system. The substance is 'labeled' by including unusual isotopes in its chemical composition...
form, in which it can be used in SPECT scanning in human neuroimaging
Neuroimaging
Neuroimaging includes the use of various techniques to either directly or indirectly image the structure, function/pharmacology of the brain...
studies, to examine the distribution of the 5-HT2A receptor subtype in the brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...
, e.g. with respect to sex
Sex
In biology, sex is a process of combining and mixing genetic traits, often resulting in the specialization of organisms into a male or female variety . Sexual reproduction involves combining specialized cells to form offspring that inherit traits from both parents...
and age
Ageing
Ageing or aging is the accumulation of changes in a person over time. Ageing in humans refers to a multidimensional process of physical, psychological, and social change. Some dimensions of ageing grow and expand over time, while others decline...
and in adults with Asperger syndrome
Asperger syndrome
Asperger's syndrome that is characterized by significant difficulties in social interaction, alongside restricted and repetitive patterns of behavior and interests. It differs from other autism spectrum disorders by its relative preservation of linguistic and cognitive development...
or Alzheimer's disease
Alzheimer's disease
Alzheimer's disease also known in medical literature as Alzheimer disease is the most common form of dementia. There is no cure for the disease, which worsens as it progresses, and eventually leads to death...
.
An alternative 5-HT2A receptor ligand also used in neuroimaging is altanserin
Altanserin
Altanserin is a compound that binds to the 5-HT2A receptor .It is a yellowish solid.Labeled with the isotope fluorine-18 it is used as a radioligand in positron emission tomography studies of the brain, i.e., studies of the serotonin-2A neuroreceptors.Besides human neuroimaging studies altanserin...
.