ChemiSCREEN Human H₂ Histamine Receptor Membrane Preparation

Full-length human HRH2 cDNA encoding H2

The histamine H2 receptor is a widely distributed G-protein coupled receptor, which is important in regulating a host of physiologic actions extending from gastric acid secretion to gastrointestinal motility (Del Valle and Gantz, 1997). Histamine mediated activation of its receptor leads to signaling through both adenylate cyclase and phosphoinositide /protein kinase C second messenger systems (Hill, 1990). Antagonists for this receptor have proven to be effective therapy for acid peptic disorders of the GI tract. Certain antagonists are used in the treatment of neuropsychiatric and neurological diseases e.g. schizophrenia, Alzheimer′s disease and Parkinson′s disease. Chemicon′s H2 membrane preparations are crude membrane preparations made from our proprietary stable recombinant cell lines to ensure high-level of GPCR surface expression; thus, they are ideal HTS tools for screening of agonists and antagonists at H2. The membrane preparations exhibit a Kd of 0.8 nM for [125I]-Iodoaminopotentidine. With 0.65 nM [125I]-Iodoaminopotentidine, 10 µg/well H2 Membrane Prep typically yields greater than 7-fold signal-to-background ratio.

Human H2 GPCR membrane preparation for Radioligand binding Assays & GTPγS binding.

Protein Target: H2

Table 1. Signal:background and specific binding values obtained in a competition binding assay with H2 membrane prep and unlabeled tiotidine.

	10 µg/well
Signal:Background	11.68
Specific Binding (cpm)	4152

SPECIFICATIONS: 1 unit = 10 µg
Bmax for [125I] Iodoaminopotentidine binding: 0.46 pmol/mg protein
Kd for [125I] Iodoaminopotentidine binding: ~0.8 nM

Inucbation Conditions
Membranes are mixed with radioactive ligand and unlabeled competitor (see Figures 1 and 2 for concentrations tested) in binding buffer in a nonbinding 96-well plate, and incubated for 1-2 h. Prior to filtration, an FC 96-well harvest plate (Millipore cat. # MAHF C1H) is coated with 0.33% polyethyleneimine for 30 min, then washed with 50mM HEPES, pH 7.4, 0.5% BSA. Binding reaction is transferred to the filter plate, and washed 3 times (1 mL per well per wash) with Wash Buffer. The plate is dried and counted.

Binding buffer: 50 mM Hepes, pH 7.4, 5 mM MgCl2, 1 mM CaCl2, 0.2% BSA, filtered and stored at 4°C
Radioligand: [125I] Iodoaminopotentidine (Amersham#: IM264)
Wash Buffer: 50 mM Hepes, pH 7.4, 500mM NaCl , 0.1% BSA, filtered and stored at 4°C.

One package contains enough membranes for at least 200 assays (units), where a unit is the amount of membrane that will yield greater than 7-fold signal:background with 125I-labeled Iodoaminopotentidine at 0.65 nM

Liquid in packaging buffer: 50 mM Tris pH 7.4, 10% glycerol and 1% BSA with no preservatives.
Packaging method: Membranes protein were adjusted to 1 mg/mL in packaging buffer, and dispensed at 1 mL/vial. Vials were rapidly frozen, and stored at -80oC.

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