title: Modulatory effects of the serotonergic and histaminergic systems on reaction to light in the crustacean Gammarus pulex.
abstract: Serotonin modulates reaction to light in many animals. In the freshwater amphipod Gammarus pulex, exogenous administration of serotonin induces a transient reversal of photic behaviour from strong photophobia to photophily. We have elucidated further the neuromodulation of photic behaviour in G. pulex by using in vivo pharmacology and behavioural testing. Using several mammalian 5-HT receptor antagonists and agonists, we provide evidence for a role of serotonin receptors in the 5-HT-dependent regulation of G. pulex photic behaviour, possibly involving 5-HTR2 subtype. Serotonin-induced photophily was blocked by the 5-HT receptor antagonists, mianserin, cyproheptadine, and ritanserin, but not by ketanserin and methiothepin. In addition, two agonists at 5-HT receptor, mCPP and α-methylserotonin, partially mimicked 5-HT-induced photophily. The natural photophobia of G. pulex was also decreased by exogenous administration of the histamine receptor antagonist cimetidine, suggesting that photic behaviour may be controlled by more complex interactions between serotonergic and histaminergic systems.
authors.affiliation: Université de Bourgogne, UMR CNRS 6282 Biogéosciences, Equipe Ecologie Evolutive, 6 Boulevard Gabriel, 21000 Dijon, France. Electronic address: mjperrot@u-bourgogne.fr.
authors.forename: Marie-Jeanne
authors.initials: MJ
authors.lastname: Perrot-Minnot
authors.affiliation: Université de Bourgogne, UMR CNRS 6282 Biogéosciences, Equipe Ecologie Evolutive, 6 Boulevard Gabriel, 21000 Dijon, France.
authors.forename: Emilie
authors.initials: E
authors.lastname: Dion
authors.affiliation: Université de Bourgogne, UMR CNRS 6282 Biogéosciences, Equipe Ecologie Evolutive, 6 Boulevard Gabriel, 21000 Dijon, France; Institut universitaire de France, France. Electronic address: fcezill@u-bourgogne.fr.
authors.forename: Frank
authors.initials: F
authors.lastname: Cézilly
mesh_terms: D033304:Amphipoda; D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D004357:Drug Synergism; D006632:Histamine / Q000378:metabolism*; D006633:Histamine Antagonists / Q000494:pharmacology; D008027:Light; D009068:Movement / Q000187:drug effects / Q000502:physiology* / Q000528:radiation effects; D012701:Serotonin / Q000378:metabolism* / Q000494:pharmacology; D018490:Serotonin Agents / Q000494:pharmacology
chemical_list: D006633:Histamine Antagonists; D018490:Serotonin Agents; D012701:Serotonin; D006632:Histamine
keywords: 5-HT receptor; Cimetidine; Cyproheptadine; Mianserin; Pharmacology; Phototaxis