title: Function and distribution of 5-HT2 receptors in the honeybee (Apis mellifera).
abstract: 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 Ca(2+) 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-HT2α and Am5-HT2β. 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 Ca(2+) 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.
authors: Department of Biochemistry and Biology, University of Potsdam, Potsdam, Germany.
authors: Markus
authors: M
authors: Thamm
authors: Daniel
authors: D
authors: Rolke
authors: Nadine
authors: N
authors: Jordan
authors: Sabine
authors: S
authors: Balfanz
authors: Christian
authors: C
authors: Schiffer
authors: Arnd
authors: A
authors: Baumann
authors: Wolfgang
authors: W
authors: Blenau
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001516:Bees / Q000502:physiology*; D003001:Cloning, Molecular; D004305:Dose-Response Relationship, Drug; D005260:Female; D005786:Gene Expression Regulation; D023061:Gene Order; D057809:HEK293 Cells; D006801:Humans; D008969:Molecular Sequence Data; D009928:Organ Specificity / Q000235:genetics; D010802:Phylogeny; D059368:RNA Isoforms; D012333:RNA, Messenger / Q000235:genetics; D044348:Receptors, Serotonin, 5-HT2 / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D058826:Serotonin 5-HT2 Receptor Agonists / Q000494:pharmacology; D058830:Serotonin 5-HT2 Receptor Antagonists / Q000494:pharmacology
chemical_list: D059368:RNA Isoforms; D012333:RNA, Messenger; D044348:Receptors, Serotonin, 5-HT2; D058826:Serotonin 5-HT2 Receptor Agonists; D058830:Serotonin 5-HT2 Receptor Antagonists