The Journal of Neuroscience, December 1, 1998, 18(23):9812-9821
The Lymnaea Cardioexcitatory Peptide (LyCEP)
Receptor: A G-Protein-Coupled Receptor for a Novel Member of the
RFamide Neuropeptide Family
Cornelis P.
Tensen1, 2,
Kingsley J. A.
Cox3,
August
B.
Smit2,
Roel C.
van der
Schors2,
Wolfgang
Meyerhof4,
Dietmar
Richter4,
Rudi J.
Planta1,
Petra M.
Hermann2,
Jan
van
Minnen2,
Wijnand P. M.
Geraerts2,
Jaco C.
Knol1,
Julian F.
Burke3,
Erno
Vreugdenhil1, and
Harm
van
Heerikhuizen1
Departments of 1 Biochemistry and Molecular Biology and
2 Molecular Neurobiology, Research Institute Neurosciences,
Vrije Universiteit, 1081 HV Amsterdam, The Netherlands,
3 Sussex Neuroscience Research Centre, School of Biological
Sciences, University of Sussex, Falmer, Brighton BN1 9QG, United
Kingdom, and 4 Institut für Zellbiochemie und
Klinische Neurobiologie, Universitäts-Krankenhaus
Eppendorf, 20246 Hamburg, Germany
A novel G-protein-coupled receptor (GRL106) resembling
neuropeptide Y and tachykinin receptors was cloned from the mollusc Lymnaea stagnalis. Application of a peptide extract from
the Lymnaea brain to Xenopus oocytes
expressing GRL106 activated a calcium-dependent chloride channel. Using
this response as a bioassay, we purified the ligand for GRL106,
Lymnaea cardioexcitatory peptide (LyCEP), an
RFamide-type decapeptide (TPHWRPQGRF-NH2) displaying
significant similarity to the Achatina cardioexcitatory
peptide (ACEP-1) as well as to the recently identified family of
mammalian prolactin-releasing peptides. In the Lymnaea
brain, the cells that produce egg-laying hormone are the predominant
site of GRL106 gene expression and appear to be innervated by
LyCEP-containing fibers. Indeed, LyCEP application transiently
hyperpolarizes isolated egg-laying hormone cells. In the
Lymnaea pericardium, LyCEP-containing fibers end blindly
at the pericardial lumen, and the heart is stimulated by LyCEP
in vitro. These data confirm that LyCEP is an RFamide ligand for GRL106.
Key words:
neuropeptide receptor; mollusc; HPLC; Xenopus
oocyte; RFamide; orphan receptor
Copyright © 1998 Society for Neuroscience 0270-6474/98/18239812-10$05.00/0