3H-DOB (4-bromo-2,5-dimethoxyphenylisopropylamine) labels a guanyl nucleotide-sensitive state of cortical 5-HT2 receptors.
R. A. Lyon, K. Davis, M. Titeler
Molecular Pharmacology February 1, 1987 DOI: 10.1016/s0026-895x(25)10354-4 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Laboratory experiment Peer reviewed |
|---|---|
| Population | Rat frontal cortex tissue homogenates |
| Topics | Serotonin |
| Citations | 106 |
| Key findings | 3H-DOB labels a small, G-protein-coupled subset of brain 5-HT2 receptors that has high affinity for agonists, whereas 3H-ketanserin labels both subsets. |
Abstract
3H-(+/-)-4-Bromo-2,5-dimethoxyphenylisopropylamine (3H-DOB), a putative agonist radioligand, was synthesized and used to label 5-HT2 receptors in a particulate fraction prepared from rat frontal cortex tissue homogenates. The specific binding (defined by the difference in 3H-DOB binding in the presence and absence of 10(-6) M cinanserin, a potent and specific 5-HT2 antagonist) displayed high affinity (KD = 4.1 X 10(-10) M) and saturability with a Bmax of 17.9 fmol/mg of protein. The distribution of specific 3H-DOB binding in nine brain regions correlated closely with the distribution of 3H-ketanserin (an antagonist radioligand)-labeled 5-HT2 receptors. Competition studies in frontal cortex homogenates using a variety of compounds revealed a distinct 5-HT2 receptor pharmacology. A series of 5-HT2 antagonists exhibited high affinities in competition studies for specific 3H-DOB binding. The absolute potencies of these antagonists as well as their order of potencies closely correlated with their potencies in competing for 3H-ketanserin-labeled brain 5-HT2 receptors. A series of 5-HT2 agonists also exhibited high affinities in competition studies for specific 3H-DOB binding. Although the order of potencies of these agonists was similar to their order in competing for 3H-ketanserin-labeled brain 5-HT2 receptors, the agonists displayed 10-100-fold higher affinities for the 3H-DOB-labeled sites than for the 3H-ketanserin-labeled sites. The level of specific 3H-DOB binding in the frontal cortex homogenates was approximately 5% of the levels of 3H-ketanserin-labeled 5-HT2 receptors (358 fmol/mg of protein). Taken together, these results indicate that 3H-DOB labels a subset of brain 5-HT2 receptors that has high affinity for agonists as well as antagonists); 3H-ketanserin appears to label both subsets of brain 5-HT2 receptors. Antagonists apparently do not discriminate between these two subsets of 5-HT2 receptors. 3H-DOB specific binding to 5-HT2 receptors was potently inhibited by guanosine 5'-(beta, gamma-imido)triphosphate and guanosine 5'-O-(3-thio)triphosphate (nonhydrolyzable derivatives of GTP) with IC50 values of 42 and 21 nM, respectively, whereas adenosine 5'-(beta, gamma-imido)triphosphate and adenosine 5'-O-(3-thio)triphosphate (nonhydrolyzable derivatives of ATP) had no effect. In summary, 3H-DOB specific binding displays the pharmacological characteristics of a 5-HT2 receptor.(ABSTRACT TRUNCATED AT 400 WORDS)
Comparable studies
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| Amphetamine-type central nervous system stimulants release norepinephrine more potently than they release dopamine and serotonin | 2000 | Experimental study | |
| Methylenedioxyamphetamine (MDA) and methylenedioxymethamphetamine (MDMA) cause selective ablation of serotonergic axon terminals in forebrain: immunocytochemical evidence for neurotoxicity Rat brain | 1988 | Experimental study | |
| The molecular mechanism of "ecstasy" [3,4-methylenedioxy-methamphetamine (MDMA)]: serotonin transporters are targets for MDMA-induced serotonin release. Human platelet plasma membrane vesicles and bovine adrenal chromaffin granule membrane... | 1992 | Laboratory study | |
| 5-HT2AReceptor-Mediated Regulation of Brain-Derived Neurotrophic Factor mRNA in the Hippocampus and the Neocortex Rat brain | 1997 | Experimental study |
Citations in the library
Cited by 16
- Dihydrobenzofuran Analogues of Hallucinogens. 4. Mescaline Derivatives Journal of Medicinal Chemistry September 1, 1997
- LSD and DOB: interaction with 5‐HT2A receptors to inhibit NMDA receptor‐mediated transmission in the rat prefrontal cortex European Journal of Neuroscience September 1, 1999
- [125I]-2-(2,5-dimethoxy-4-iodophenyl)aminoethane ([125I]-2C-I) as a label for the 5-HT2 receptor in rat frontal cortex. Pharmacology, Biochemistry, and Behavior 1990
- Behavioral effects of α,α,β,β-tetradeutero-5-MeO-DMT in rats: comparison with 5-MeO-DMT administered in combination with a monoamine oxidase inhibitor. Psychopharmacology June 1, 2012
- Receptor Pharmacology of MDMA and Related Hallucinogensa Annals of the New York Academy of Sciences October 1, 1990
and 11 more in the library