We investigated the pharmacology of three novel compounds, Org 27569 (5-chloro-3-ethyl-1H-indole-2-carboxylic acid [2-(4-piperidin-1-yl-phenyl)-ethyl]-amide), Org 27759 (3-ethyl-5-fluoro-1H-indole-2-carboxylic acid [2-94-dimethylamino-phenyl)-ethyl]-amide), and Org 29647 (5-chloro-3-ethyl-1H-indole-2-carboxylic acid (1-benzyl-pyrrolidin-3-yl)-amide, 2-enedioic acid salt), at the cannabinoid CB1...

The existence and localization of brain angiotensin receptors is well established. However, questions regarding the endogenous ligand for brain angiotensin type 1 (AT(1)) receptors necessitates re-examination of brain angiotensin receptor binding studies. To assess the ability of angiotensin II to bind to the brain AT(1) receptor, radioligand binding studies of rat brain AT(1) receptors were pe...

The concentration of estrogen receptor protein in breast-tumortissue is generallyexpressed in units of femtomoles of estradiol bound by the receptor per milligram of cytosol protein. The sensitivity of the estrogen receptor radioligand assay is therefore related to the specific activity of the steroid label used for the binding assay, the amount of the receptor protein in the volume of cytosolu...

We have recently developed 1-([3-O-methyl-11C]3,4-dimethoxyphenethyl)-4-(3-phenylpropyl) piperazine ([11C]SA4503) as a selective radioligand for mapping sigma1 receptors in the brain by positron emission tomography (PET). In the present short communication we evaluated the age-related changes of the binding of this ligand to sigma1 receptors in Fisher-344 rats (1.5-, 6-, 12-, and 24-month-old) ...

Radioligand binding assays take advantage of the ability to detect the decay of radioactive material, which can be incorporated into a ligand of choice. The interaction of such a radioligand with a receptor preparation can subsequently be determined by capturing and measuring the amount of radioactivity present. Radioligand binding assays can be used to estimate molecular parameters, such as th...

Background [11C]Cimbi-36 is a serotonin 2A receptor agonist positron emission tomography radioligand that has recently been examined in humans. The binding of agonist radioligand is expected to be more sensitive to endogenous neurotransmitter concentrations than antagonist radioligands. In the current study, we compared the effect of serotonin releaser fenfluramine on the binding of [11C]Cimbi-...

The luteinizing hormone (LH) receptor plays a pivotal role in reproduction. The high-molecular-weight (HMW) human chorionic gonadotropin (hCG) and LH are the endogenous ligands of this receptor and bind to its large N terminus. The present study characterizes the binding of a new low-molecular-weight (LMW) radioligand, [(3)H]5-amino-2-methylsulfanyl-4-[3-(2-morpholin-4-yl-acetylamino)-phenyl]-t...

Interaction with the exsorptive transporter P-glycoprotein (P-gp) is a possible source of peculiarities in drug pharmacokinetics, including dose-dependent absorption, drug-drug interactions, intestinal secretion, and limited permeability of the blood-brain barrier. Among the established in vitro methods of the analysis of drug interactions with P-gp, none directly quantifies the affinity of lig...

The present study describes the implementation of comparative molecular field analysis (CoMFA) to develop two 3D-QSAR (quantitative structure-activity relationship) models (CoMFA models 1 and 2) of the cannabimimetic (aminoalkyl)indoles (AAIs) for CB1 cannabinoid receptor binding affinity, based on pKi values measured using radioligand binding assays that displace two different agonist ligands,...

Guinea pig lung membranes were extracted with 1% digitonin and yielded a preparation that contained soluble leukotriene D4 (LTD4) receptor. Specific binding of the high affinity radiolabeled receptor antagonist [3H]ICI-198615 to the soluble LTD4 receptor was time dependent and reversible. The dissociation constant (Kd) and the density (Bmax) of [3H]ICI-198615 binding to the soluble LTD4 recepto...