Serotonin localization in Phallusia mammillata larvae and effects of 5-HT antagonists during larval development.
The neurotransmitter 5-hydroxytryptamine (5-HT, serotonin) plays an important role in a wide range of non-neural processes. Using immunofluorescence with an antiserotonin antibody, 5-HT was localized in the brain and in some neurons of the larval tail of Phallusia mammillata. To test the effect of 5-HT on development, we treated embryos with two different 5-HT receptor subtype antagonists. Treatment at the gastrula stage with 10 microM ondansetron, an antagonist of the 5-HT(3) receptor, induced anterior truncation and a short tail. At 10 microM, ritanserin, a 5-HT(2B) receptor antagonist, induced larval phenotypes characterized by a roundish trunk region with flat papillae. The juveniles developed from these larvae had an abnormal cardiocirculatory system: their heart contractions were ineffective and their blood cells accumulated in the heart cavity. We conclude that an appropriate level of 5-HT is necessary for correct development and morphogenesis. Moreover, a different key role for multiple receptors in modulating the morphogenetic effects of 5-HT is suggested.
Pennati
R
R
Department of Biology, Section of Zoology SN 7B, University of Milano, via Celoria 26, 20133 Milano, Italy. sirob@mailserver.unimi.it
Groppelli
S
S
Sotgia
C
C
Candiani
S
S
Pestarino
M
M
De Bernardi
F
F
D000818:Animals; D005455:Fluorescent Antibody Technique; D007814:Larva / Q000187:drug effects / Q000378:metabolism*; D017294:Ondansetron / Q000494:pharmacology*; D010641:Phenotype; D016713:Ritanserin / Q000494:pharmacology*; D012701:Serotonin / Q000378:metabolism*; D012702:Serotonin Antagonists / Q000494:pharmacology*; D014561:Urochordata / Q000254:growth & development*
D012702:Serotonin Antagonists; D016713:Ritanserin; D012701:Serotonin; D017294:Ondansetron