title: Influence of mRNA and protein synthesis inhibitors on the long-term memory acquisition of classically conditioned earthworms.
abstract: We investigated the process of memory consolidation following classical conditioning of earthworms. Earthworms were conditioned in paired trials by a weak vibration as a conditioned stimulus (CS), and by light as an unconditioned stimulus (US). The occurrence of a shrinking response upon exposure to the CS increased steadily with the number of paired training trials. When the training procedure was changed by increasing the intertrial interval (ITI), it was found that only those worms trained with a 68 s ITI exhibited long-term memory retention for at least 24 h. The influence of mRNA synthesis inhibition by actinomycin-D or of protein synthesis by anisomycin on memory consolidation was also examined. Induction of the long-term memory was blocked when either of these two compounds was injected into the body cavity of the worm within 25 min of conditioning with the 68 s ITI. These results demonstrate that the long-term memory is dependent upon protein synthesis in response to the upregulation of new transcription messengers.
authors.affiliation: Center for Life Science and Technology, School of Fundamental Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan. hikaru@bpni.bio.keio.ac.jp
authors.forename: Hikaru
authors.initials: H
authors.lastname: Watanabe
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Takaya
authors.forename: Toshinobu
authors.initials: T
authors.lastname: Shimoi
authors.forename: Hiroto
authors.initials: H
authors.lastname: Ogawa
authors.forename: Yoshiichiro
authors.initials: Y
authors.lastname: Kitamura
authors.forename: Kotaro
authors.initials: K
authors.lastname: Oka
mesh_terms: D000818:Animals; D000841:Anisomycin / Q000494:pharmacology*; D001245:Association Learning / Q000187:drug effects / Q000502:physiology; D001362:Avoidance Learning / Q000187:drug effects / Q000502:physiology; D003609:Dactinomycin / Q000494:pharmacology*; D007267:Injections; D011939:Mental Recall / Q000187:drug effects / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000037:antagonists & inhibitors* / Q000502:physiology*; D009424:Nervous System Physiological Phenomena / Q000187:drug effects; D009835:Oligochaeta / Q000187:drug effects / Q000502:physiology*; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology*; D012333:RNA, Messenger / Q000037:antagonists & inhibitors* / Q000502:physiology*; D012153:Retention, Psychology / Q000187:drug effects* / Q000502:physiology*; D013998:Time Perception / Q000187:drug effects / Q000502:physiology; D014732:Vibration
chemical_list: D009419:Nerve Tissue Proteins; D011500:Protein Synthesis Inhibitors; D012333:RNA, Messenger; D003609:Dactinomycin; D000841:Anisomycin