title: FMRFamide-related peptides and serotonin regulate Drosophila melanogaster heart rate: mechanisms and structure requirements.
abstract: Drosophila melanogaster FMRFamide-related peptides (FaRPs) include SDNFMRFamide, PDNFMRFamide, and TDVDHVFLRFamide (dromyosuppressin, DMS); each peptide contains a C-terminal FMRFamide but a different N-terminal extension. FaRPs and serotonin (5-HT) each affect the frequency of D. melanogaster heart contractions in vivo. We examined the cellular expression of FaRPs and 5-HT, and the activities of FMRFamide, SDNFMRFamide, PDNFMRFamide, or DMS and 5-HT on heart rate. FaRPs and 5-HT were not co-localized; FaRP-and 5-HT-immunoreactive fibers extended from different brain cells and innervated the anterior D. melanogaster dorsal vessel. However, no neuron expressed both a FaRP and 5-HT. The effect of FMRFamide and 5-HT was not different from the effect of 5-HT alone on heart rate. The effect of PDNFMRFamide and 5-HT showed an additive effect on heart rate. SDNFMRFamide and 5-HT or DMS and 5-HT resulted in non-additive effects on heart rate. Our data provide evidence for the complexity of FaRP and 5-HT interactions to regulate frequency of heart contractions in vivo. Our results also confirm the biological importance of FaRP N-terminal amino acid extensions.
authors.affiliation: University of Michigan Medical School, Biological Chemistry Department, 4444 Medical Science Building I, Ann Arbor, MI 48109-0606, USA. nicholsr@umich.edu
authors.forename: Ruthann
authors.initials: R
authors.lastname: Nichols
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002490:Central Nervous System / Q000502:physiology; D004331:Drosophila melanogaster / Q000502:physiology*; D019835:FMRFamide / Q000502:physiology*; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D008297:Male; D011679:Pupa / Q000502:physiology; D012701:Serotonin / Q000494:pharmacology*; D013329:Structure-Activity Relationship
chemical_list: D012701:Serotonin; D019835:FMRFamide