Serotonin receptor cDNA cloned from Lymnaea stagnalis.
Serotonin (5-HT) is a major neurotransmitter that influences various behaviors, neuronal plasticity, learning, and memory in molluscs. Although the physiology of 5-HT transmission in molluscs is well studied, little is known about the pharmacology and diversity of the 5-HT receptor system. Based on the high homology of genes coding for guanine nucleotide-binding protein (G protein)-coupled receptors, we have cloned a gene for the Lymnaea stagnalis 5-HT (5HTlym) receptor. The putative receptor protein, 509 amino acids long, has highest homology with the Drosophila 5-HT receptors and mammalian 5HT1 receptors. As revealed by RNA blot-hybridization analysis, two mRNA species of 2.3 and 3.2 kb are detected in the central nervous system of Lymnaea. Transient expression of 5HTlym in COS-7 cells showed saturable [3H]lysergic acid diethylamide binding with an estimated dissociation constant of 0.9 nM. The 5HTlym receptor exhibited a mixed 5HT-like pharmacology that cannot be precisely categorized with existing mammalian classification nomenclature. However, the 5HTlym receptor does display some characteristics that have been attributed to the putative mammalian vascular 5HT1-like receptor.
Sugamori
K S
KS
Department of Pharmacology, University of Toronto, Ontario, Canada.
Sunahara
R K
RK
Guan
H C
HC
Bulloch
A G
AG
Tensen
C P
CP
Seeman
P
P
Niznik
H B
HB
Van Tol
H H
HH
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001667:Binding, Competitive; D015152:Blotting, Northern; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics*; D006801:Humans; D008195:Lymnaea / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides; D010802:Phylogeny; D011061:Poly A / Q000235:genetics / Q000302:isolation & purification; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics / Q000302:isolation & purification; D011985:Receptors, Serotonin / Q000235:genetics* / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014162:Transfection
D009838:Oligodeoxyribonucleotides; D012333:RNA, Messenger; D011985:Receptors, Serotonin; D011994:Recombinant Proteins; D011061:Poly A; D004247:DNA