TY - JOUR A1 - Thamm, Markus A1 - Balfanz, Sabine A1 - Scheiner, Richarda A1 - Baumann, Arnd A1 - Blenau, Wolfgang T1 - Characterization of the 5-HT1A receptor of the honeybee (Apis mellifera) and involvement of serotonin in phototactic behavior N2 - Serotonin plays a key role in modulating various physiological and behavioral processes in both protostomes and deuterostomes. The vast majority of serotonin receptors belong to the superfamily of G-protein-coupled receptors. We report the cloning of a cDNA from the honeybee (Am5-ht1A) sharing high similarity with members of the 5-HT1 receptor class. Activation of Am5-HT1A by serotonin inhibited the production of cAMP in a dose-dependent manner (EC50 = 16.9 nM). Am5-HT1A was highly expressed in brain regions known to be involved in visual information processing. Using in vivo pharmacology, we could demonstrate that Am5-HT1A receptor ligands had a strong impact on the phototactic behavior of individual bees. The data presented here mark the first comprehensive study-from gene to behavior-of a 5-HT1A receptor in the honeybee, paving the way for the eventual elucidation of additional roles of this receptor subtype in the physiology and behavior of this social insect. Y1 - 2010 UR - http://www.springerlink.com/content/101193 U6 - https://doi.org/10.1007/s00018-010-0350-6 SN - 1420-682X ER - TY - JOUR A1 - Thamm, Markus A1 - Rolke, Daniel A1 - Jordan, Nadine A1 - Balfanz, Sabine A1 - Schiffer, Christian A1 - Baumann, Arnd A1 - Blenau, Wolfgang T1 - Function and distribution of 5-HT2 receptors in the honeybee (apis mellifera) JF - PLoS one N2 - Background: Serotonin plays a pivotal role in regulating and modulating physiological and behavioral processes in both vertebrates and invertebrates. In the honeybee (Apis mellifera), serotonin has been implicated in division of labor, visual processing, and learning processes. Here, we present the cloning, heterologous expression, and detailed functional and pharmacological characterization of two honeybee 5-HT2 receptors. Methods: Honeybee 5-HT2 receptor cDNAs were amplified from brain cDNA. Recombinant cell lines were established constitutively expressing receptor variants. Pharmacological properties of the receptors were investigated by Ca2+ imaging experiments. Quantitative PCR was applied to explore the expression patterns of receptor mRNAs. Results: The honeybee 5-HT2 receptor class consists of two subtypes, Am5-HT2 alpha and Am5-HT2 beta. Each receptor gene also gives rise to alternatively spliced mRNAs that possibly code for truncated receptors. Only activation of the full-length receptors with serotonin caused an increase in the intracellular Ca2+ concentration. The effect was mimicked by the agonists 5-methoxytryptamine and 8-OH-DPAT at low micromolar concentrations. Receptor activities were blocked by established 5-HT receptor antagonists such as clozapine, methiothepin, or mianserin. High transcript numbers were detected in exocrine glands suggesting that 5-HT2 receptors participate in secretory processes in the honeybee. Conclusions: This study marks the first molecular and pharmacological characterization of two 5-HT2 receptor subtypes in the same insect species. The results presented should facilitate further attempts to unravel central and peripheral effects of serotonin mediated by these receptors. Y1 - 2013 U6 - https://doi.org/10.1371/journal.pone.0082407 SN - 1932-6203 VL - 8 IS - 12 PB - PLoS CY - San Fransisco ER - TY - JOUR A1 - Röser, Claudia A1 - Jordan, Nadine A1 - Balfanz, Sabine A1 - Baumann, Arnd A1 - Walz, Bernd A1 - Baumann, Otto A1 - Blenau, Wolfgang T1 - Molecular and pharmacological characterization of serotonin 5-HT2 alpha and 5-HT7 receptors in the salivary glands of the blowfly calliphora vicina JF - PLoS one N2 - Secretion in blowfly (Calliphora vicina) salivary glands is stimulated by the biogenic amine serotonin (5-hydroxytryptamine, 5-HT), which activates both inositol 1,4,5-trisphosphate (InsP(3))/Ca2+ and cyclic adenosine 3',5'-monophosphate (cAMP) signalling pathways in the secretory cells. In order to characterize the signal-inducing 5-HT receptors, we cloned two cDNAs (Cv5-ht2 alpha, Cv5-ht7) that share high similarity with mammalian 5-HT2 and 5-HT7 receptor genes, respectively. RT-PCR demonstrated that both receptors are expressed in the salivary glands and brain. Stimulation of Cv5-ht2 alpha-transfected mammalian cells with 5-HT elevates cytosolic [Ca2+] in a dose-dependent manner (EC50 = 24 nM). In Cv5-ht7-transfected cells, 5-HT produces a dose-dependent increase in [cAMP](i) (EC50 = 4 nM). We studied the pharmacological profile for both receptors. Substances that appear to act as specific ligands of either Cv5-HT2 alpha or Cv5-HT7 in the heterologous expression system were also tested in intact blowfly salivary gland preparations. We observed that 5-methoxytryptamine (100 nM) activates only the Cv(5)-HT2 alpha receptor, 5-carboxamidotryptamine (300 nM) activates only the Cv5-HT7 receptor, and clozapine (1 mu M) antagonizes the effects of 5-HT via Cv5-HT7 in blowfly salivary glands, providing means for the selective activation of each of the two 5-HT receptor subtypes. This study represents the first comprehensive molecular and pharmacological characterization of two 5-HT receptors in the blowfly and permits the analysis of the physiological role of these receptors, even when co-expressed in cells, and of the modes of interaction between the Ca2+- and cAMP-signalling cascades. Citation: Roser C, Jordan N, Balfanz S, Baumann A, Walz B, et al. (2012) Molecular and Pharmacological Characterization of Serotonin 5-HT2a and 5-HT7 Receptors in the Salivary Glands of the Blowfly Calliphora vicina. Y1 - 2012 U6 - https://doi.org/10.1371/journal.pone.0049459 SN - 1932-6203 VL - 7 IS - 11 PB - PLoS CY - San Fransisco ER - TY - JOUR A1 - Blankenburg, Stefanie A1 - Balfanz, Sabine A1 - Hayashi, Y. A1 - Shigenobu, S. A1 - Miura, T. A1 - Baumann, Otto A1 - Baumann, Arnd A1 - Blenau, Wolfgang T1 - Cockroach GABA(B) receptor subtypes: Molecular characterization, pharmacological properties and tissue distribution JF - Neuropharmacology N2 - gamma-aminobutyric acid (GABA) is the predominant inhibitory neurotransmitter in the central nervous system (CNS). Its effects are mediated by either ionotropic GABA(A) receptors or metabotropic GABA(B) receptors. GABA(B) receptors regulate, via Gi/o, G-proteins, ion channels, and adenylyl cyclases. In humans, GABA(B) receptor subtypes are involved in the etiology of neurologic and psychiatric disorders. In arthropods, however, these members of the G-protein-coupled receptor family are only inadequately characterized. Interestingly, physiological data have revealed important functions of GABA(B) receptors in the American cockroach, Periplaneta americana. We have cloned cDNAs coding for putative GABA(B) receptor subtypes 1 and 2 of P. americana (PeaGB1 and PeaGB2). When both receptor proteins are co-expressed in mammalian cells, activation of the receptor heteromer with GABA leads to a dose-dependent decrease in cAMP production. The pharmacological profile differs from that of mammalian and Drosophila GABA(B) receptors. Western blot analyses with polyclonal antibodies have revealed the expression of PeaGB1 and PeaGB2 in the CNS of the American cockroach. In addition to the widespread distribution in the brain, PeaGB1 is expressed in salivary glands and male accessory glands. Notably, PeaGB1-like immunoreactivity has been detected in the GABAergic salivary neuron 2, suggesting that GABA(B) receptors act as autoreceptors in this neuron. KW - GABA(B) receptor KW - G-protein-coupled receptor KW - Periplaneta americana KW - Central nervous system KW - Adenylyl cyclase KW - Salivary gland Y1 - 2015 U6 - https://doi.org/10.1016/j.neuropharm.2014.08.022 SN - 0028-3908 SN - 1873-7064 VL - 88 SP - 134 EP - 144 PB - Elsevier CY - Oxford ER -