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Keywords:

agonist, antagonist, drosophila, g protein, neuropeptide, tachykinin, spantide, tachykinin-related peptides, cell-lines, stomoxytachykinin receptor, negligible neurotoxicity, drosophila-melanogaster, gene-expression, high potency, family, homology, Animals, Cell Line, Dose-Response Relationship, Drug, Drosophila, Drosophila Proteins, Evolution, Molecular, Insects, Ligands, Neuropeptides, Receptors, Neurotransmitter, Receptors, Tachykinin, Substance P, Tachykinins, Science & Technology, Life Sciences & Biomedicine, Biochemistry & Molecular Biology, Endocrinology & Metabolism, Pharmacology & Pharmacy, G protein, TACHYKININ-RELATED PEPTIDES, CELL-LINES, STOMOXYTACHYKININ RECEPTOR, NEGLIGIBLE NEUROTOXICITY, DROSOPHILA-MELANOGASTER, GENE-EXPRESSION, HIGH POTENCY, NEUROPEPTIDE, FAMILY, HOMOLOGY, Insecta, 0304 Medicinal and Biomolecular Chemistry, 0606 Physiology, 1115 Pharmacology and Pharmaceutical Sciences, 3101 Biochemistry and cell biology, 3202 Clinical sciences, 3404 Medicinal and biomolecular chemistry

Abstract:

Tachykinins are multifunctional neuropeptides that have been identified in vertebrates as well as invertebrates. The C-terminal FXGXRa-motif constitutes the consensus active core region of invertebrate tachykinins. In Drosophila, two putative G protein-coupled tachykinin receptors have been cloned: DTKR and NKD. This study focuses on the functional characterization of DTKR, the Drosophila ortholog of the stable fly's tachykinin receptor (STKR). Tachykinins containing an alanine residue instead of the highly conserved glycine (FXAXRa) display partial agonism on STKR-mediated Ca2+-responses, but not on cAMP-responses. STKR therefore seems to differentiate between a number of tachykinins. Gly- and Ala-containing tachykinins are both encoded in the Drosophila tachykinin precursor, thus raising the question of whether DTKR can also distinguish between these two tachykinin types. DTKR was activated by all Drosophila tachykinins and inhibited by tachykinin antagonists. Ala-containing analogs did not produce the remarkable activation behavior previously observed with STKR, suggesting different mechanisms of discerning ligands and/or activating effector pathways for STKR and DTKR. (c) 2006 Elsevier Inc. All rights reserved.