title: Identification of a calcitonin-like diuretic hormone that functions as an intrinsic modulator of the American lobster, Homarus americanus, cardiac neuromuscular system.
abstract: In insects, a family of peptides with sequence homology to the vertebrate calcitonins has been implicated in the control of diuresis, a process that includes mixing of the hemolymph. Here, we show that a member of the insect calcitonin-like diuretic hormone (CLDH) family is present in the American lobster, Homarus americanus, serving, at least in part, as a powerful modulator of cardiac output. Specifically, during an ongoing EST project, a transcript encoding a putative H. americanus CLDH precursor was identified; a full-length cDNA was subsequently cloned. In silico analyses of the deduced prepro-hormone predicted the mature structure of the encoded CLDH to be GLDLGLGRGFSGSQAAKHLMGLAAANFAGGPamide (Homam-CLDH), which is identical to a known Tribolium castaneum peptide. RT-PCR tissue profiling suggests that Homam-CLDH is broadly distributed within the lobster nervous system, including the cardiac ganglion (CG), which controls the movement of the neurogenic heart. RT-PCR analysis conducted on pacemaker neuron- and motor neuron-specific cDNAs suggests that the motor neurons are the source of the CLDH message in the CG. Perfusion of Homam-CLDH through the isolated lobster heart produced dose-dependent increases in both contraction frequency and amplitude and a dose-dependent decrease in contraction duration, with threshold concentrations for all parameters in the range 10(-11) to 10(-10) mol l(-1) or less, among the lowest for any peptide on this system. This report is the first documentation of a decapod CLDH, the first demonstration of CLDH bioactivity outside the Insecta, and the first detection of an intrinsic neuropeptide transcript in the crustacean CG.
authors.affiliation: Center for Marine Functional Genomics, Mount Desert Island Biological Laboratory, PO Box 35, Old Bar Harbor Road, Salisbury Cove, ME 04672, USA. achristi@mdibl.org
authors.forename: A E
authors.initials: AE
authors.lastname: Christie
authors.forename: J S
authors.initials: JS
authors.lastname: Stevens
authors.forename: M R
authors.initials: MR
authors.lastname: Bowers
authors.forename: M C
authors.initials: MC
authors.lastname: Chapline
authors.forename: D A
authors.initials: DA
authors.lastname: Jensen
authors.forename: K M
authors.initials: KM
authors.lastname: Schegg
authors.forename: J
authors.initials: J
authors.lastname: Goldwaser
authors.forename: M A
authors.initials: MA
authors.lastname: Kwiatkowski
authors.forename: T K
authors.initials: TK
authors.lastname: Pleasant
authors.forename: L
authors.initials: L
authors.lastname: Shoenfeld
authors.forename: L K
authors.initials: LK
authors.lastname: Tempest
authors.forename: C R
authors.initials: CR
authors.lastname: Williams
authors.forename: T
authors.initials: T
authors.lastname: Wiwatpanit
authors.forename: C M
authors.initials: CM
authors.lastname: Smith
authors.forename: K M
authors.initials: KM
authors.lastname: Beale
authors.forename: D W
authors.initials: DW
authors.lastname: Towle
authors.forename: D A
authors.initials: DA
authors.lastname: Schooley
authors.forename: P S
authors.initials: PS
authors.lastname: Dickinson
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002116:Calcitonin / Q000031:analogs & derivatives*; D002302:Cardiac Output; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D004232:Diuretics / Q000032:analysis / Q000302:isolation & purification / Q000378:metabolism; D006728:Hormones / Q000032:analysis / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism*; D008969:Molecular Sequence Data; D009206:Myocardium / Q000737:chemistry; D008121:Nephropidae / Q000378:metabolism*
chemical_list: D018076:DNA, Complementary; D004232:Diuretics; D006728:Hormones; D002116:Calcitonin