title: The 5-HT- and FMRFa-activated signaling pathways interact at the level of the Erk MAPK cascade: potential inhibitory constraints on memory formation.
abstract: The sensorimotor synapse of Aplysia exhibits long-term facilitation (LTF) and long-term depression (LTD) elicited by the neuromodulator serotonin (5-HT) and the peptide Phe-Met-Arg-Phe-NH(2), respectively. 5-HT-induced LTF engages extracellular-regulated kinase (Erk) and CREB1, whereas FMRFa-induced LTD engages p38 MAPK (mitogen-activated protein kinase) and CREB2. The interaction of the 5-HT and FMRFa pathways was recently investigated in Aplysia at the level of gene expression. However, little is known about crosstalk of these pathways at the level of the second messenger cascades. We investigated the potential interaction of the 5-HT and FMRFa pathways at the level of the Erk cascade. We found that FMRFa inhibited basal Erk activity through p38 MAPK. FMRFa also inhibited 5-HT-induced phosphorylation of Erk and nuclear accumulation of phospho-ERK, suggesting that FMRFa may place inhibitory constraints on memory formation through regulation of the Erk MAPK cascade.
authors.affiliation: Department of Neurobiology and Anatomy, W.M. Keck Center for the Neurobiology of Learning and Memory, The University of Texas Medical School at Houston, 77030, USA.
authors.forename: Diasinou
authors.initials: D
authors.lastname: Fioravante
authors.forename: Paul D
authors.initials: PD
authors.lastname: Smolen
authors.forename: John H
authors.initials: JH
authors.lastname: Byrne
mesh_terms: D000818:Animals; D001048:Aplysia; D015153:Blotting, Western / Q000379:methods; D004347:Drug Interactions; D004586:Electrophoresis / Q000379:methods; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D019835:FMRFamide / Q000494:pharmacology*; D049990:Membrane Transport Modulators / Q000494:pharmacology*; D051379:Mice; D008954:Models, Biological; D009433:Neural Inhibition / Q000187:drug effects; D012701:Serotonin / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects* / Q000502:physiology
chemical_list: D049990:Membrane Transport Modulators; D012701:Serotonin; D019835:FMRFamide; D048049:Extracellular Signal-Regulated MAP Kinases