Procedure for calculation of potency and efficacy for ligands acting on Gs- and Gi-coupled receptors.

Structure activity relationship (SAR) analyses of pharmacological data of compounds constitute an important part of the discovery process in the design of new drug candidates with improved pharmacological properties. In particular G-Protein Coupled Receptors (GPCRs) associated with the cAMP second messenger systems G(s) and G(i) have constituted one of the most widely used basis for pharmacological in vitro assays for assessing functional receptor effects. Such assays are based on Radio Immuno Assay (RIA) analysis to measure the cellular cAMP concentration as readout of receptor activation.

The antiarrhythmic peptide analog rotigaptide (ZP123) stimulates gap junction intercellular communication in human osteoblasts and prevents decrease in femoral trabecular bone strength in ovariectomized rats.

Gap junctions play an important role in bone development and function, but the lack of pharmacological tools has hampered the gap junction research. The antiarrhythmic peptides stimulate gap junction communication between cardiomyocytes, but effects in noncardiac tissue are unknown. The purpose of this study was to examine whether antiarrhythmic peptides, which are small peptides increasing gap junctional conductivity, show specific binding to osteoblasts and investigate the effect of the stable analog rotigaptide (ZP123) on gap junctional intercellular communication in vitro and on bone mass and strength in vivo.

Pharmacodynamic characterization of ZP120 (Ac-RYYRWKKKKKKK-NH2), a novel, functionally selective nociceptin/orphanin FQ peptide receptor partial agonist with sodium-potassium-sparing aquaretic activity.

In conscious rats, intravenous (i.v.) administration of the hexapeptide Ac-RYYRWK-NH(2), a partial agonist of the nociceptin/orphanin FQ (N/OFQ) peptide (NOP) receptor, produces a selective water diuresis without marked cardiovascular or behavioral effects.

Opioid receptor-like 1 stimulation in the collecting duct induces aquaresis through vasopressin-independent aquaporin-2 downregulation.

Nociceptin, the endogenous ligand of the inhibitory G protein-coupled opioid receptor-like 1 receptor, produces aquaresis (i.e., increases the excretion of solute-free urine) in rats.

Glucagon-like peptide 1 receptor agonist ZP10A increases insulin mRNA expression and prevents diabetic progression in db/db mice.

We characterized the novel, rationally designed peptide glucagon-like peptide 1 (GLP-1) receptor agonist H-HGEGTFTSDLSKQMEEEAVRLFIEWLKNGGPSSGAPPSK KKKKK-NH2 (ZP10A). Receptor binding studies demonstrated that the affinity of ZP10A for the human GLP-1 receptor was 4-fold greater than the affinity of GLP-1 (7-36) amide. ZP10A demonstrated dose-dependent improvement of glucose tolerance with an ED50 value of 0.

Lu 28-179 labels a sigma(2)-site in rat and human brain.

1'-[4-[1-(4-Fluorophenyl)-1H-indol-3-yl]-1-butyl]spiro[isobenzofuran-1(3H),4'-piperidine] (Lu 28-179) or Siramesine is a sigma-ligand with high specificity for sigma(2)-sites, has been tritiated to directly label these sites in brain. [(3)H]Lu 28-179 bound in a saturable manner to homogenates prepared from rat brain or human cortices with high affinity (K(d)=2.2 and 1.