Estimates of dopamine D(2/3) receptor occupancy by endogenous dopamine using positron emission tomography (PET) in animals have varied almost threefold. This variability may have been caused by incomplete depletion of dopamine or by the use of antagonist radioligands, which appear less sensitive than agonist radioligands to changes in endogenous dopamine. PET scans were performed in rats with t...

Physiological and pharmacological studies of hormones, drugs, and neurotransmitters often generate families of sigmoidal dose-response curves. Optimally efficient data analysis should involve simultaneous description of all curves, rather than fitting each one individually. We have developed a general computerized method to describe the dose-response curves in terms of basal and maximal respons...

melanocortin-1 (mc1) receptor is an attractive melanoma-specific target for the development of α-msh peptide based imaging and therapeutic agents. in this work a new lactam bridge α-msh analogue was synthesized and radiolabeled with 99mtc via hynic chelator and tricine as co-ligand. also, stability in human serum, receptor bound internalization and tissue biodistribution in tumor bearing nude m...

The Smoothened receptor (Smo) mediates hedgehog (Hh) signaling critical for development, cell growth, and migration, as well as stem cell maintenance. Aberrant Hh signaling pathway activation has been implicated in a variety of cancers, and small-molecule antagonists of Smo have entered human clinical trials for the treatment of cancer. Here, we report the biochemical characterization of allost...

Estimates of dopamine D2/3 receptor occupancy by endogenous dopamine using positron emission tomography (PET) in animals have varied almost threefold. This variability may have been caused by incomplete depletion of dopamine or by the use of antagonist radioligands, which appear less sensitive than agonist radioligands to changes in endogenous dopamine. PET scans were performed in rats with the...

The present study was designed to examine the specificity of (3-adrenergic antagonists for al-, 192-adrenergic and 5HT1B-serotonergic receptors by the compe titive interaction with 1251-iodocyanopindolol (1251-ICYP) as a radioligand. The 81 -adrenoceptors were preferred by acebutolol, atenolol, betaxolol, practolol, and I-, dl and d-metoprolol, while butoxamine and ICI-118,551 preferred 82-adre...

Porphyromonas gingivalis 381 cells were incubated with 125I-histidine-rich polypeptide (histatin) 5 in the presence or absence of unlabeled histatin 5, to evaluate the histatin-binding capacity of the cells. The binding of histatin 5 was rapid, reversible, saturable and specific. The number of histatin 5-binding sites per cell was 3,600, and the dissociation constant (Kd) was in the order of 10...

The defining characteristic of the binding sites of any particular molecularly imprinted material is heterogeneity: that is, they are not all identical. Nonetheless, it is useful to study their fundamental binding properties, and to obtain average properties. In particular, it has been instructive to compare the binding properties of imprinted and non-imprinted materials. This chapter begins by...

We showed previously that the calcineurin B subunit (CnB) plays an important role in activation of peritoneal macrophage, but the underlying mechanism remained unknown. To examine whether there is a CnB receptor on peritoneal macrophages, we performed the radioligand binding assay of receptors. The receptor saturation binding curve demonstrated high-affinity and specific binding; the maximum bi...

Protean agonists are of great pharmacological interest as their behavior may change in magnitude and direction depending on the constitutive activity of a receptor. Yet, this intriguing phenomenon has been poorly described and understood, due to the lack of stable experimental systems and design strategies. In this study, we overcome both limitations: First, we demonstrate that modulation of th...