ELISA法定量测定大鼠血清、血浆或其它相关液体中Orexin A含量。

 

本试剂盒应用双抗体夹心酶标免疫分析法测定标本中Orexin A水平。用纯化的抗体包被微孔板，制成固相抗体，往包被单抗的微孔中依次加入Orexin A抗原、生物素化的抗大鼠Orexin A抗体、HRP标记的亲和素，经过彻底洗涤后用底物TMB显色。TMB在过氧化物酶的催化下转化成蓝色，并在酸的作用下转化成最终的黄色。颜色的深浅和样品中的Orexin A呈正相关。用酶标仪在450nm波长下测定吸光度（OD值），计算样品浓度。

 

This immunoassay kit allows for the specific measurement of Rat Orexin A concentrations in cell culture supernates, serum and plasma.

 

Orexins, also called hypocretins, are the common names given to a pair of highly excitatory neuropeptide hormones that were simultaneously discovered by two groups of researchers in rat brains.The two related peptides (orexin A and B, or hypocretin-1 and -2), with approximately 50% sequence identity, are produced by cleavage of a single precursor protein. Studies suggest that orexin A/hypocretin-1 may be of greater biological importance than orexin B/hypocretin-2. Although these peptides are produced by a very small population of cells in the lateral and posterior hypothalamus, they send projections throughout the brain.

The orexins/hypocretins are strongly conserved peptides, found in all major classes of vertebrates. The peptides are thought to have arisen early in vertebrate evolution.The orexin/hypocretin system was initially suggested to be primarily involved in the stimulation of food intake, based on the finding that central administration of orexin A/hypocretin-1 increases food intake. The discovery that orexin/hypocretin dysregulation causes the sleep disorder narcolepsy subsequently indicated a major role for this system in sleep regulation.

Leptin is a hormone produced by fat cells and acts as a long-term internal measure of energy state. Ghrelin is a short term factor secreted by the stomach just before an expected meal, and strongly promotes food intake.Orexin-producing cells have recently been shown to be inhibited by glucose but are activated by ghrelin.

Hypocretin-producing cells have recently been shown to be inhibited by leptin (by leptin receptors) but are activated by ghrelin and hypoglycemia. Orexin/hypocretin (as of 2007) is therefore a very important link between metabolism and sleep regulation. Such a relationship has been long suspected based on the observation that long-term sleep deprivation in rodents dramatically increases food intake and energy metabolism, i.e. catabolism, with lethal consequences on a long term basis.

 

This assay employs the quantitative sandwich enzyme immunoassay technique. A monoclonal antibody specific for Orexin A has been pre-coated onto a microplate. Standards and samples are pipetted into the wells and any Orexin A present is bound by the immobilized antibody. An enzyme-linked monoclonal antibody specific for Orexin A is added to the wells. Following a wash to remove any unbound antibody-enzyme reagent, a substrate solution is added to the wells and color develops in proportion to the amount of Orexin A bound in the initial step. The color development is stopped and the intensity of the color is measured.