TY - JOUR A1 - Thamm, Markus A1 - Scholl, Christina A1 - Reim, Tina A1 - Gruebel, Kornelia A1 - Moeller, Karin A1 - Rossler, Wolfgang A1 - Scheiner, Ricarda T1 - Neuronal distribution of tyramine and the tyramine receptor AmTAR1 in the honeybee brain JF - The journal of comparative neurology N2 - Tyramine is an important neurotransmitter, neuromodulator, and neurohormone in insects. In honeybees, it is assumed to have functions in modulating sensory responsiveness and controlling motor behavior. Tyramine can bind to two characterized receptors in honeybees, both of which are coupled to intracellular cAMP pathways. How tyramine acts on neuronal, cellular and circuit levels is unclear. We investigated the spatial brain expression of the tyramine receptor AmTAR1 using a specific antibody. This antibody detects a membrane protein of the expected molecular weight in western blot analysis. In honeybee brains, it labels different structures which process sensory information. Labeling along the antennal nerve, in projections of the dorsal lobe and in the gnathal ganglion suggest that tyramine receptors are involved in modulating gustatory and tactile perception. Furthermore, the ellipsoid body of the central complex and giant synapses in the lateral complex show AmTAR1-like immunoreactivity (AmTAR1-IR), suggesting a role of this receptor in modulating sky-compass information and/or higher sensor-motor control. Additionally, intense signals derive from the mushroom bodies, higher-order integration centers for olfactory, visual, gustatory and tactile information. To investigate whether AmTAR1-expressing brain structures are in vicinity to tyramine releasing sites, a specific tyramine antibody was applied. Tyramine-like labeling was observed in AmTAR1-IR positive structures, although it was sometimes weak and we did not always find a direct match of ligand and receptor. Moreover, tyramine-like immunoreactivity was also found in brain regions without AmTAR1-IR (optic lobes, antennal lobes), indicating that other tyramine-specific receptors may be expressed there. KW - antibody KW - biogenic amines KW - G-protein coupled receptor KW - honeybee KW - tyramine Y1 - 2017 U6 - https://doi.org/10.1002/cne.24228 SN - 0021-9967 SN - 1096-9861 VL - 525 SP - 2615 EP - 2631 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Scheiner, Ricarda A1 - Toteva, Anna A1 - Reim, Tina A1 - Sovik, Eirik A1 - Barron, Andrew B. T1 - Differences in the phototaxis of pollen and nectar foraging honey bees are related to their octopamine brain titers JF - Frontiers in physiology N2 - The biogenic amine octopamine is an important neuromodulator, neurohormone and neurotransmitter in insects. We here investigate the role of octopamine signaling in honey bee phototaxis. Our results show that groups of bees differ naturally in their phototaxis. Pollen forgers display a lower light responsiveness than nectar foragers. The lower phototaxis of pollen foragers coincides with higher octopamine titers in the optic lobes but is independent of octopamine receptor gene expression. Increasing octopamine brain titers reduces responsiveness to light, while tyramine application enhances phototaxis. These findings suggest an involvement of octopamine signaling in honey bee phototaxis and possibly division of labor, which is hypothesized to be based on individual differences in sensory responsiveness. KW - biogenic amines KW - tyramine KW - division of labor KW - honey bee KW - light responsiveness KW - insect KW - behavior Y1 - 2014 U6 - https://doi.org/10.3389/fphys.2014.00116 SN - 1664-042X VL - 5 PB - Frontiers Research Foundation CY - Lausanne ER -