Autoradiographic localization of 5HT2 receptors in rat brain using [125I]-DOI, a selective psychotomimetic radioligand. 1989

A J Nazarali, and D J McKenna, and J M Saavedra
Laboratory of Clinical Science, National Institute of Mental Health, Bethesda, Maryland.

1. Binding sites for the R and S enantiomers of the 5HT2 agonist DOI (2,5-dimethoxy-4-iodophenylisopropylamine) were identified in rat brain using quantitative in-vitro autoradiography and compared with [125I]-LSD binding. 2. In most regions of the brain, binding density of the less active isomer [125I]S-DOI was 15 to 85% of that exhibited by the active [125I]R-DOI isomer. 3. Cortical membrane preparations exhibited two binding sites, of the enantiomers with high (KdH) and low (KdL) affinity constants of 1.2 +/- 0.02 nM and 29 +/- 7 nM for the [125I]R-DOI and 2.1 +/- 0.2 nM and 18 +/- 4 nM for [125I]S-DOI respectively. The respective high (BmaxH) and low (BmaxL) binding densities were 92 +/- 10 and 536 +/- 164 fmol/mg protein for the [125I]R-DOI and 67 +/- 19 and 245 +/- 60 fmol/mg protein for [125I]S-DOI. 4. Our results correlate with regional distribution of 5HT2 receptors reported in previous studies and indicate that DOI and its congeners have potential clinical applications for the in-vivo localization of 5HT2 receptors.

UI MeSH Term Description Entries
D007457 Iodine Radioisotopes Unstable isotopes of iodine that decay or disintegrate emitting radiation. I atoms with atomic weights 117-139, except I 127, are radioactive iodine isotopes. Radioisotopes, Iodine
D007700 Kinetics The rate dynamics in chemical or physical systems.
D008297 Male Males
D008566 Membranes Thin layers of tissue which cover parts of the body, separate adjacent cavities, or connect adjacent structures. Membrane Tissue,Membrane,Membrane Tissues,Tissue, Membrane,Tissues, Membrane
D009928 Organ Specificity Characteristic restricted to a particular organ of the body, such as a cell type, metabolic response or expression of a particular protein or antigen. Tissue Specificity,Organ Specificities,Specificities, Organ,Specificities, Tissue,Specificity, Organ,Specificity, Tissue,Tissue Specificities
D011919 Rats, Inbred Strains Genetically identical individuals developed from brother and sister matings which have been carried out for twenty or more generations or by parent x offspring matings carried out with certain restrictions. This also includes animals with a long history of closed colony breeding. August Rats,Inbred Rat Strains,Inbred Strain of Rat,Inbred Strain of Rats,Inbred Strains of Rats,Rat, Inbred Strain,August Rat,Inbred Rat Strain,Inbred Strain Rat,Inbred Strain Rats,Inbred Strains Rat,Inbred Strains Rats,Rat Inbred Strain,Rat Inbred Strains,Rat Strain, Inbred,Rat Strains, Inbred,Rat, August,Rat, Inbred Strains,Rats Inbred Strain,Rats Inbred Strains,Rats, August,Rats, Inbred Strain,Strain Rat, Inbred,Strain Rats, Inbred,Strain, Inbred Rat,Strains, Inbred Rat
D011985 Receptors, Serotonin Cell-surface proteins that bind SEROTONIN and trigger intracellular changes which influence the behavior of cells. Several types of serotonin receptors have been recognized which differ in their pharmacology, molecular biology, and mode of action. 5-HT Receptor,5-HT Receptors,5-Hydroxytryptamine Receptor,5-Hydroxytryptamine Receptors,Receptors, Tryptamine,Serotonin Receptor,Serotonin Receptors,Tryptamine Receptor,Tryptamine Receptors,Receptors, 5-HT,Receptors, 5-Hydroxytryptamine,5 HT Receptor,5 HT Receptors,5 Hydroxytryptamine Receptor,5 Hydroxytryptamine Receptors,Receptor, 5-HT,Receptor, 5-Hydroxytryptamine,Receptor, Serotonin,Receptor, Tryptamine,Receptors, 5 HT,Receptors, 5 Hydroxytryptamine
D001921 Brain The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM. Encephalon
D002540 Cerebral Cortex The thin layer of GRAY MATTER on the surface of the CEREBRAL HEMISPHERES that develops from the TELENCEPHALON and folds into gyri and sulci. It reaches its highest development in humans and is responsible for intellectual faculties and higher mental functions. Allocortex,Archipallium,Cortex Cerebri,Cortical Plate,Paleocortex,Periallocortex,Allocortices,Archipalliums,Cerebral Cortices,Cortex Cerebrus,Cortex, Cerebral,Cortical Plates,Paleocortices,Periallocortices,Plate, Cortical
D000662 Amphetamines Analogs or derivatives of AMPHETAMINE. Many are sympathomimetics and central nervous system stimulators causing excitation, vasopressin, bronchodilation, and to varying degrees, anorexia, analepsis, nasal decongestion, and some smooth muscle relaxation.

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