Opioid agonists and antagonists can regulate the density of mu-opioid receptors in whole animal and in cell culture. High intrinsic efficacy agonists (e.g., etorphine), but not lower intrinsic efficacy agonists (e.g., morphine), produce mu-opioid receptor down-regulation and can alter the abundance of mu-opioid receptor mRNA. Conversely, opioid antagonists substantially increase the density of ...

GMP-140 is a rapidly inducible receptor for neutrophils and monocytes expressed on activated platelets and endothelial cells. It is a member of the selectin family of lectin-like cell surface molecules that mediate leukocyte adhesion. We used a radioligand binding assay to characterize the interaction of purified GMP-140 with human neutrophils. Unstimulated neutrophils rapidly bound [125I]GMP-1...

A new microassay in which cryostat sections of prostate tissue were used to provide the source of soluble androgen receptor for biochemical assay, was devised using an isoelectric focusing method, with [3H]-mibolerone as the androgenic radioligand. Adjacent cryostat sections from the same tissue block were stained for diagnostic and quantitative histological assessment. The assay was used to il...

the vasopressin v2 receptor belongs to the large family of the g-protein coupled receptors and is responsible for the antidiuretic effect of the neurohypophyseal hormone arginine vasopressin (avp). based on bioinformatic studies it seems that ala300 and asp297 of the v2 vasopressin receptor (v2r) are involved in receptor binding. ala300glu mutation resulted in lower energy while asp297tyr mutat...

BACKGROUND A downregulation of I(2)-imidazoline binding sites has been reported in frontal cortices of depressed suicide victims, according to I(2)-radioligand binding and confirmed by Western blotting. We now report Western blots of imidazoline receptor proteins in hippocampi of subjects with and without depression at the time of death. METHODS Postmortem diagnoses were obtained from 17 case...

Four sesquiterpenes, beta-selinene, isocurcumenol, nootkatone and aristolone and one triterpene, oleanolic acid were isolated from the ethylacetate fraction of the rhizomes of Cyperus rotundus and tested for their ability to modulate gamma-aminobutyric acid (GABA(A))-benzodiazepine receptor function by radioligand binding assays using rat cerebrocortical membranes. Among these compounds, only i...

ft-Receptors constitute only 10-30% of the total 0-adrenergic receptors in mammalian ventricular myocardium, but their precise tissue location cannot be determined easily by measuring physiological variables. To delineate the distribution of /3-receptor subtypes in myocytic and vascular components of the heart, we incubated transmural sections of canine left ventricle with [Iodo]cyanopindolol a...

Analogues of L-arginine with modifications at the terminal guanidino nitrogen and/or the carboxyl terminus of the molecule have been widely used for their ability to inhibit the production of nitric oxide and are thought to be competitive antagonists of nitric oxide synthase. The present studies were designed to test the possibility that these agents are also muscarinic receptor antagonists. Ac...

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...

Oxytocin (OXT) is a pleiotropic regulator of physiology and behavior. An emerging body of evidence demonstrates a role for OXT in the transition to postnatal life of the infant. To identify potential sites of OXT action via the OXT receptor (OXTR) in the newborn mouse, we performed receptor autoradiography on 20 μm sagittal sections of whole postnatal day 0 male and female mice on a C57BL/6J ba...