Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P20366 (substance P)
 21,176 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Changes in intracellular calcium concentration are important in mediating a wide variety of physiological responses. Recently there has been renewed interest in the use of aequorin, a protein from jellyfish that emits light when calcium is bound, to measure calcium levels in cells. We have loaded populations of cells from the human glioma line, U373MG, with aequorin. Lysis of aequorin-loaded but not control cells with detergent resulted in a luminescence signal that was dependent on extracellular calcium. Aequorin-loaded cells responded to substance P, histamine, or the calcium ionophore, ionomycin, with an increase in luminescence. Signals in response to detergent, ionomycin, or substance P could be detected up to 48 h after cells were loaded with aequorin. Other neurokinin-1 agonists but not agonists at neurokinin-2 or neurokinin-3 receptors produced luminescence signals. Neurokinin-1 antagonists inhibited the substance P-induced signal. The aequorin-loading procedure worked well with U373MG cells but not with AR42J, CHO, IMR-90, or WI-38 cells.
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PMID:Measurement of intracellular calcium in cell populations loaded with aequorin: neurokinin-1 responses in U373MG cells. 866 May 4

Leucokinins are insect neuropeptides that stimulate hindgut motility and renal fluid secretion. Drosophila has a single leucokinin gene, pp, encoding the longest known leucokinin, Drosokinin. To identify its receptor, a genome-wide scan for G-protein-coupled receptors was performed in silico and candidate receptors identified by similarity to known tachykinin receptors. The deduced peptides were expressed, with a transgene for the calcium reporter aequorin, in S2 cells and only one gene (CG10626) encoded a protein that responded to Drosokinin. The properties of the heterologously expressed receptor (action through intracellular calcium with an EC(50) of 4 x 10(-11) m and a t(1/2) <1 s) match closely those reported for the action of Drosokinin on Malpighian (renal) tubules. Antibodies raised against the receptor identified known sites of leucokinin action: stellate cells of the Malpighian tubule, two triplets of cells in the pars intercerebralis of the adult central nervous system, and additional cells in larval central nervous system. Western blots and reverse transcription-PCR confirmed these locations, but also identified expression in male and female gonads. These tissues also displayed elevated calcium in response to Drosokinin, demonstrating novel roles for leucokinin. A functional genomic approach has thus yielded the first complete characterization of a leucokinin receptor in an insect.
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PMID:Systematic G-protein-coupled receptor analysis in Drosophila melanogaster identifies a leucokinin receptor with novel roles. 1216 86

The bioluminescent Ca(2+)-sensitive reporter protein, aequorin, was employed to develop an insect cell-based functional assay system for monitoring receptor-mediated changes of intracellular Ca(2)(+)-concentrations. Drosophila Schneider 2 (S2) cells were genetically engineered to stably express both apoaequorin and the insect tachykinin-related peptide receptor, STKR. Lom-TK III, an STKR agonist, was shown to elicit concentration-dependent bioluminescent responses in these S2-STKR-Aeq cells. The EC(50) value for the calcium effect detected by means of aequorin appeared to be nearly identical to the one that was measured by means of Fura-2, a fluorescent Ca(2)(+)-indicator. In addition, this aequorin-based method was also utilised to study receptor antagonists. Experimental analysis of the effects exerted by spantide I, II and III, three potent substance P antagonists, on Lom-TK III-stimulated S2-STKR-Aeq cells showed that these compounds antagonise STKR-mediated responses in a concentration-dependent manner. The rank order of inhibitory potencies was spantide III > spantide II > spantide I.
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PMID:Recombinant aequorin as a reporter for receptor-mediated changes of intracellular Ca2+ -levels in Drosophila S2 cells. 1248 71

Drosophila tachykinin receptor, a neurokinin receptor cloned from the fruit fly Drosophila melanogaster, is a G-protein-coupled receptor, which upon activation by a peptide agonist induces a transient increase in the concentration of intracellular calcium. The functional assay based on aequorin-derived luminescence triggered by receptor-mediated changes in Ca(2+) levels was used to examine and compare the effect of tachykinin-related peptides from different species. Among the endogenous Drosophila peptides, Drm-TK I induced the strongest calcium response. The most potent tachykinin-related peptides from Leucophaea maderae, Locusta migratoria, and Calliphora vomitoria, were partial agonists at the Drosophila tachykinin receptor.
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PMID:Characterization of tachykinin-related peptides from different insect species on Drosophila tachykinin receptor-expressing cell line. 1717 89

A series of 3-aryl-5-acylpiperazinyl-pyrazoles (e.g., 3a-b) initially identified through a high-throughput screening campaign using the aequorin Ca(2+) bioluminescence assay as novel, potent small molecule antagonists of the G protein-coupled human tachykinin NK(3) receptor (hNK3-R) is described. Preliminary profiling revealed poor plasma and metabolic stability for these structures in rodents. Further optimization efforts resulted in analogs with improved potency, stability, and pharmacokinetic properties as well as good brain permeability, for example, compounds 26 and 42. Unexpected cytotoxicity was observed in such N-Me pyrazole structures as compounds 41-42.
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PMID:Discovery of 3-aryl-5-acylpiperazinyl-pyrazoles as antagonists to the NK3 receptor. 2137 85