Biomaterial Database

Characterization of [3H]RX821002 binding to alpha-2 adrenergic receptor subtypes. 1994

M F O'Rourke, and H S Blaxall, and L J Iversen, and D B Bylund

Department of Pharmacology, University of Nebraska Medical Center, Omaha.

Alpha-2 adrenergic receptors have been divided into four pharmacological subtypes based on their differences in affinity for several drugs. Previous studies showed that [3H]RX821002 has a high affinity for the alpha-2A subtype. The current study characterized the binding properties of [3H]RX821002 [2-(2-methoxy-1,4- benzodioxan-2yl)-2-imidazoline] to the alpha-2A receptor in CHO-C10 cells, alpha-2B in neonatal rat lung, alpha-2C in OK cells and alpha-2D in bovine pineal gland. Membrane binding studies of [3H]RX821002 were done in 25 mM glycylglycine buffer at room temperature. The nonspecific binding rates at the KD concentration were 4.9%, 20%, 14% and 8.3% of the total for CHO-C10, neonatal rat lung, OK cells and bovine pineal, respectively, which were determined by adding 100 microM norepinephrine. Saturation curves indicate that [3H]RX821002 has a high affinity for all alpha-2 adrenergic subtypes. The KD values were 0.29, 1.05, 0.37 and 0.19 nM for CHO-C10, neonatal rat lung, OK cells and bovine pineal, respectively. [3H]Rauwolscine has affinities of 0.34, 0.55 and 0.24 nM for the alpha-2A, -2B and -2C subtypes. By contrast, [3H]rauwolscine has a much lower affinity for alpha-2D subtype with a KD value of 5.2 nM. The binding site density for [3H]RX821002 was significantly lower in the neonatal rat lung compared with [3H]rauwolscine. The correlation coefficients of pKi values of adrenergic compounds against [3H]RX821002 versus [3H]rauwolscine were close to unity for each tissue. These data clearly show that the two ligands label the same alpha-2 adrenergic receptor population.(ABSTRACT TRUNCATED AT 250 WORDS)

UI	MeSH Term	Description	Entries
D008297	Male		Males
D011869	Radioligand Assay	Quantitative determination of receptor (binding) proteins in body fluids or tissue using radioactively labeled binding reagents (e.g., antibodies, intracellular receptors, plasma binders).	Protein-Binding Radioassay,Radioreceptor Assay,Assay, Radioligand,Assay, Radioreceptor,Assays, Radioligand,Assays, Radioreceptor,Protein Binding Radioassay,Protein-Binding Radioassays,Radioassay, Protein-Binding,Radioassays, Protein-Binding,Radioligand Assays,Radioreceptor Assays
D002417	Cattle	Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.	Beef Cow,Bos grunniens,Bos indicus,Bos indicus Cattle,Bos taurus,Cow,Cow, Domestic,Dairy Cow,Holstein Cow,Indicine Cattle,Taurine Cattle,Taurus Cattle,Yak,Zebu,Beef Cows,Bos indicus Cattles,Cattle, Bos indicus,Cattle, Indicine,Cattle, Taurine,Cattle, Taurus,Cattles, Bos indicus,Cattles, Indicine,Cattles, Taurine,Cattles, Taurus,Cow, Beef,Cow, Dairy,Cow, Holstein,Cows,Dairy Cows,Domestic Cow,Domestic Cows,Indicine Cattles,Taurine Cattles,Taurus Cattles,Yaks,Zebus
D004146	Dioxanes	Compounds that contain the structure 1,4-dioxane.
D005260	Female		Females
D006224	Cricetinae	A subfamily in the family MURIDAE, comprising the hamsters. Four of the more common genera are Cricetus, CRICETULUS; MESOCRICETUS; and PHODOPUS.	Cricetus,Hamsters,Hamster
D000317	Adrenergic alpha-Antagonists	Drugs that bind to but do not activate alpha-adrenergic receptors thereby blocking the actions of endogenous or exogenous adrenergic agonists. Adrenergic alpha-antagonists are used in the treatment of hypertension, vasospasm, peripheral vascular disease, shock, and pheochromocytoma.	Adrenergic alpha-Receptor Blockaders,alpha-Adrenergic Blocking Agents,alpha-Adrenergic Receptor Blockaders,alpha-Blockers, Adrenergic,Adrenergic alpha-Blockers,alpha-Adrenergic Antagonists,alpha-Adrenergic Blockers,Adrenergic alpha Antagonists,Adrenergic alpha Blockers,Adrenergic alpha Receptor Blockaders,Agents, alpha-Adrenergic Blocking,Antagonists, alpha-Adrenergic,Blockaders, Adrenergic alpha-Receptor,Blockaders, alpha-Adrenergic Receptor,Blockers, alpha-Adrenergic,Blocking Agents, alpha-Adrenergic,Receptor Blockaders, alpha-Adrenergic,alpha Adrenergic Antagonists,alpha Adrenergic Blockers,alpha Adrenergic Blocking Agents,alpha Adrenergic Receptor Blockaders,alpha Blockers, Adrenergic,alpha-Antagonists, Adrenergic,alpha-Receptor Blockaders, Adrenergic
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D014316	Tritium	The radioactive isotope of hydrogen also known as hydrogen-3. It contains two NEUTRONS and one PROTON in its nucleus and decays to produce low energy BETA PARTICLES.	Hydrogen-3,Hydrogen 3
D015016	Yohimbine	A plant alkaloid with alpha-2-adrenergic blocking activity. Yohimbine has been used as a mydriatic and in the treatment of ERECTILE DYSFUNCTION.	Rauwolscine,Aphrodine Hydrochloride,Aphrodyne,Corynanthine,Corynanthine Tartrate,Pluriviron,Rauhimbine,Yocon,Yohimbin Spiegel,Yohimbine Houdé,Yohimbine Hydrochloride,Yohimex,Hydrochloride, Aphrodine,Hydrochloride, Yohimbine,Tartrate, Corynanthine