Abbreviations used: [Ca2+]i, intracellular concentration of Ca2+; cAMP, cyclic AMP; [cAMP]i, intracellular concentration of cyclic AMP; G protein, GTP-binding protein; HEK, human embryonic kidney; PKA, cyclic AMP-dependent protein kinase; PKC, protein kinase C; PKG, cyclic GMP-dependent protein kinase; SSC, saline-sodium citrate; TM, transmembrane.
Characterization of a Gene from Honeybee (Apis mellifera) Brain Encoding a Functional Tyramine Receptor
Version of Record online: 19 MAR 2003
Journal of Neurochemistry
Volume 74, Issue 3, pages 900–908, March 2000
How to Cite
Blenau, W., Balfanz, S. and Baumann, A. (2000), Amtyr1. Journal of Neurochemistry, 74: 900–908. doi: 10.1046/j.1471-4159.2000.0740900.x
- Issue online: 19 MAR 2003
- Version of Record online: 19 MAR 2003
- Cyclic AMP;
- G protein-coupled receptor;
- Stable transformation
Abstract: Biogenic amine receptors are involved in the regulation and modulation of various physiological and behavioral processes in both vertebrates and invertebrates. We have cloned a member of this gene family from the CNS of the honeybee, Apis mellifera. The deduced amino acid sequence is homologous to tyramine receptors cloned from Locusta migratoria and Drosophila melanogaster as well as to an octopamine receptor cloned from Heliothis virescens. Functional properties of the honeybee receptor were studied in stably transfected human embryonic kidney 293 cells. Tyramine reduced forskolin-induced cyclic AMP production in a dose-dependent manner with an EC50 of ∼130 nM. A similar effect of tyramine was observed in membrane homogenates of honeybee brains. Octopamine also reduced cyclic AMP production in the transfected cell line but was both less potent (EC50 of ∼3 μM) and less efficacious than tyramine. Receptor-encoding mRNA has a widespread distribution in the brain and subesophageal ganglion of the honeybee, suggesting that this tyramine receptor is involved in sensory signal processing as well as in higher-order brain functions.