( sup 3 H)-DOB(4-bromo-2,5-dimethoxyphenylisopropylamine) and ( sup 3 H) ketanserin label two affinity states of the cloned human 5-hydroxytryptamine2 receptor

Journal Article · Thu Nov 01 00:00:00 EST 1990 · Molecular Pharmacology; (USA)

OSTI ID:6324950

Branchek, T; Adham, N; Macchi, M; Kao, H T; Hartig, P R ^[1]

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1. Neurogenetic Corporation, Paramus, NJ (USA)

The binding properties of the 5-hydroxytryptamine2 (5-HT2) receptor have been the subject of much interest and debate in recent years. The hallucinogenic amphetamine derivative 4-bromo-2,5-dimethoxyphenylisopropylamine (DOB) has been shown to bind to a small number of binding sites with properties very similar to (3H)ketanserin-labeled 5-HT2 receptors, but with much higher agonist affinities. Some researchers have interpreted this as evidence for the existence of a new subtype of 5-HT2 receptor (termed 5-HT2A), whereas others have interpreted these data as indicative of agonist high affinity and agonist low affinity states for the 5-HT2 receptor. In this investigation, a cDNA clone encoding the serotonin 5-HT2 receptor was transiently transfected into monkey kidney Cos-7 cells and stably transfected into mouse fibroblast L-M(TK-) cells. In both systems, expression of this single serotonin receptor cDNA led to the appearance of both (3H)DOB and (3H)ketanserin binding sites with properties that matched their binding characteristics in mammalian brain homogenates. Addition of guanosine 5'-(beta, gamma-imido) triphosphate (Gpp(NH)p) to this system caused a rightward shift and steepening of agonist competition curves for (3H) ketanserin binding, converting a two-site binding curve to a single low affinity binding state. Gpp(NH)p addition also caused a 50% decrease in the number of high affinity (3H)DOB binding sites, with no change in the dissociation constant of the remaining high affinity states. These data on a single human 5-HT2 receptor cDNA expressed in two different transfection host cells indicate that (3H)DOB and (3H)ketanserin binding reside on the same gene product, apparently interacting with agonist and antagonist conformations of a single human 5-HT2 receptor protein.

• OSTI ID: 6324950
• Journal Information: Molecular Pharmacology; (USA), Vol. 38:5; ISSN 0026-895X
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
HALLUCINOGENS
BIOCHEMICAL REACTION KINETICS
RECEPTORS
LABELLING
TRYPTAMINES
AFFINITY
ANIMAL CELLS
CHEMICAL PROPERTIES
DNA
GENES
GENETIC ENGINEERING
MICE
MONKEYS
NUCLEOTIDES
TRACER TECHNIQUES
TRITIUM COMPOUNDS
AMINES
ANIMALS
AROMATICS
AZAARENES
AZOLES
CENTRAL NERVOUS SYSTEM AGENTS
DRUGS
HETEROCYCLIC COMPOUNDS
HYDROGEN COMPOUNDS
INDOLES
ISOTOPE APPLICATIONS
KINETICS
MAMMALS
MEMBRANE PROTEINS
NUCLEIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PRIMATES
PROTEINS
PSYCHOTROPIC DRUGS
PYRROLES
REACTION KINETICS
RODENTS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques