title: Acute administration of a permeant analog of cAMP and a phosphodiesterase inhibitor improve long-term habituation in the crab Chasmagnathus.
abstract: A shadow passing overhead acts as a danger stimulus and elicits an escape response in the crab Chasmagnathus that habituates promptly and for a long period. Robust retention is shown at 24 h after 15 trials of shadow presentation or at 120 h after 30 trials, but no significant retention is disclosed at 24 h after 5 trials or at 72 h after 15. A cocktail of the cAMP membrane permeable analog 8-(4-chlorophenylthio)-cAMP (CPT-cAMP), plus the phosphodiesterase inhibitor isobutyl methylxanthine (IBMX), was given by systemic administration. Pretraining injection of the cocktail (25 or 50 microM, 15 min before a 5-trial session) failed to affect short-term habituation, but induced significant retention when tested at 24 h. This facilitatory effect was not shown when a lower dose (5 microM) was used. A post-training injection of 25 microM, immediately after a 5- or 15-trial session, induced retention when tested at 24 or 72 h, respectively. Thus, the administration of CPT-cAMP + IBMX during acquisition of a habituated response or immediately after, improves long-term habituation, a result supporting the view that an increase in the cAMP level is one of the steps in long-term memory consolidation.
authors.affiliation: Departamento de Biología, Facultad de Ciencias Exactas y Naturales, Buenos Aires University, Argentina.
authors.forename: A
authors.initials: A
authors.lastname: Romano
authors.forename: A
authors.initials: A
authors.lastname: Delorenzi
authors.forename: M E
authors.initials: ME
authors.lastname: Pedreira
authors.forename: D
authors.initials: D
authors.lastname: Tomsic
authors.forename: H
authors.initials: H
authors.lastname: Maldonado
mesh_terms: D015056:1-Methyl-3-isobutylxanthine / Q000494:pharmacology; D000818:Animals; D003386:Brachyura / Q000502:physiology*; D000242:Cyclic AMP / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004924:Escape Reaction / Q000187:drug effects; D006185:Habituation, Psychophysiologic / Q000187:drug effects*; D008297:Male; D008568:Memory / Q000187:drug effects; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology*; D013873:Thionucleotides / Q000494:pharmacology*
chemical_list: D010726:Phosphodiesterase Inhibitors; D013873:Thionucleotides; C015929:8-((4-chlorophenyl)thio)cyclic-3',5'-AMP; D000242:Cyclic AMP; D015056:1-Methyl-3-isobutylxanthine