Characterisation of receptors

Characterisation of receptors, including aquatic ecosystems, dependent terrestrial ecosystems and groundwater. 

Wright AJ, Higginbottom A, Philippe D et al. Characterisation of receptor binding by the chemotaxis inhibitory protein of Staphylococcus aureus and the eficcts of the host immune response. Mol Immunol 2007 44 2507-2517. 

Probably the most notable feature of this receptor is the confusion arising from its classification and nomenclature Soon after characterisation of the 5-HTid receptor, which was found in certain species (e.g. the human) it was determined that this was in fact a variant of the 5-HTib receptor which had already been found in other species (e.g. the rat). These receptors were therefore regarded as species variants and came to be described as the 5-HTib/id subtype. Since then, another 5-HTi receptor subtype has been identified and current nomenclature dictates that this is the (new) 5-HTid receptor. 

Unlike other transmitter systems, there are no obvious meehanisms for dampening glutamate release. Presynaptic autoreceptors for glutamate are mostly of the kainate type (see below) and appear to act as positive rather than negative influenees on further release of the amino acid. Although poorly characterised at present, inhibitory autoreceptors of the metabotropic type of receptors may act to inhibit release of glutamate. 

Leppik RA, Lazareno S, Mynett A, Birdsall NJM. Characterisation of the allosteric interactions between antagonists and amiloride analogues at the human alpha2A adrenergic receptor. Mol Pharmacol 1998 53 916-925. 

Clarke, V. R. J. and Collingridge, G. L. (2002) Characterisation of the effects of ATPA, a GLUk5 receptor selective agonist, on excitatory synaptic transmission in area CA1 of rat hippocampal slices. Neuropharmacology 42, 889-902. 

Receptors for interferon-7 on the neutrophil have not been characterised in detail. Mature human macrophages possess two types of receptor (/Qji = 4.3 X 10"10 M K 2 = 6.4 x 10-9 M) whereas on monocytes there is only one class of receptor (1600 sites per cell) with an affinity of = 1 x 10 9 M. 

Because the fMet-Leu-Phe receptor is present only at low levels in neutrophils (-12 x 10 15 g of receptor per cell), it has proved difficult to purify and characterise. Researchers have therefore turned to molecular cloning techniques to gain insight into the molecular structure of this receptor. This approach itself has not been easy because, in the absence of an antibody that specifically binds to the receptor, or else without some amino acid sequence data that can be used to synthesise oligonucleotide probes, cDNA libraries cannot be screened to isolate relevant clones. Therefore, experimental systems in which functional fMet-Leu-Phe receptors are expressed on the surfaces of transfected cells have been used. Two main systems have been utilised expression of mRNA injected into Xenopus laevis oocytes and cDNA cloning into the COS-cell expression vector. 

Boulay, F., Tardif, M., Brouchon, L., Vignais, P. (1990b). The human / /-formylpeptide receptor Characterisation of two cDNA isolates and evidence for a new subfamily of G-protein-coupled receptors. Biochemistry 29, 11123-33. 

Newton RA, Phipps SL, Flanigan TP, Newberry NR, Carey JE, Kumar C, McDonald B, Chen C, Elliott JM. (1996). Characterisation of human 5-hydroxytryptamine2A and 5-hydroxytryptamine2C receptors expressed in the human neuroblastoma cell line SH-SY5Y comparative stimulation by hallucinogenic drugs. J Neurochem. 67(6) 2521-31. 

Watanabe N, Ikeno A, Minato H, et al. Discovery and preclinical characterisation of (-l-)-3-[4-(l-piperidinoethoxy)phenyl]spiro[indene-l,l -indane]-5,5 -diol hydrochloride a promising nonsteroidal estrogen receptor agonist for hot flush. / Med Chem 2003 46 3961-4. 

The role of the steroid hormone receptors has extensively been defined with the help of natural and synthetic agonists and antagonists and with characterisation of transgenic and knock-out mice. In experimental studies, both approaches have been useful tools for validating that a physiological process is indeed mediated by the steroid hormone receptor imder investigation. 

Advances in the production, immobilisation and characterisation of mammalian olfactory receptors led to the development of biosensors where isolated olfactory binding proteins were deposited on the surface of QMBs [102, 103] or were connected to nanoelectrodes [104]. Although still at the development stage, such an array-type device coated with different olfactory receptors will be a powerful and useful tool for detecting and discriminating odorants in the future. 

Grimwood, S., Richards, P., Murray, F., Harrison, N., Wingrove, P. B., Hutson, P. H. Characterisation of N-methyl-D-aspartate receptor-specific fHjifenprodil binding to recombinant human NR1a/NR2B receptors compared with native receptors in rodent brain membranes, J. Neurosci. 2000, 75, 2455-2463. 

Priestley, T., Laughton, P., Macaulay, A. J., Hill, R. G., Kemp, J. A. Electrophysiological characterisation of the antagonist properties of two novel NMDA receptor glycine site antagonists, L-695,902 and L-701,324, Neuropharmacology 1996, 35, 1573-1581. 

The characterisation of a fruit type or variety will be reflected in the flavour profile of its volatile components. Analytical techniques can produce an accurate peak profile using gas chromatography, but in simpler terms the sensory receptors of most individuals can quickly differentiate between fruit varieties. We have four basic taste senses, sometimes described as sweet, sour, acid and bitter, and these are identified by taste receptors situated mainly on the tongue. The key component of flavour differentiation, so-called top-notes and the like, is detected not so much by taste as by aroma in the nasal cavity. Thus, during the process of eating and drinking, the release of aroma volatiles can be identified and an assessment of their value arrived at. 

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