Food-aversive classical conditioning increases a persistent sodium current in molluscan withdrawal interneurons in a transcription dependent manner.
In this study we examined changes in a persistent sodium current (I(NaP)) after behavioral aversive classical conditioning in the snail Helix pomatia. We trained animals by pairing food with a mild electric shock that triggered the whole-body withdrawal reflex. This aversive training resulted in transcription dependent long-term associative memory. Isolated central nervous system preparations were set up from trained, random control and naive animals and using two-electrode voltage clamp methods, I(NaP) was activated and measured in identified body withdrawal interneurons RPa3 and LPa3. We show here that in preparations from conditioned animals I(NaP) is increased, suggesting that modifications in intrinsic cellular properties contribute to the formation of the memory trace. Blocking RNA synthesis by systemic injection of actinomycin D (0.12microM) suppressed both memory consolidation in intact animals and the learning-induced increase of I(NaP) in withdrawal interneurons, suggesting that aversive classical conditioning affects sodium channel expression at the transcriptional level.
Kiss
Tibor
T
Department of Zoology, Balaton Limnological Research Institute, Hungarian Academy of Sciences, Tihany, Hungary.
Pirger
Zsolt
Z
Kemenes
György
G
D000704:Analysis of Variance; D000818:Animals; D003214:Conditioning, Classical / Q000187:drug effects / Q000502:physiology*; D003609:Dactinomycin / Q000008:administration & dosage; D004597:Electroshock; D005247:Feeding Behavior / Q000502:physiology*; D006372:Helix, Snails / Q000187:drug effects / Q000502:physiology*; D007395:Interneurons / Q000187:drug effects / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects; D008568:Memory / Q000187:drug effects / Q000502:physiology; D019384:Nucleic Acid Synthesis Inhibitors / Q000008:administration & dosage; D018408:Patch-Clamp Techniques; D012313:RNA / Q000096:biosynthesis / Q000187:drug effects; D012964:Sodium / Q000378:metabolism*; D014158:Transcription, Genetic / Q000187:drug effects
D019384:Nucleic Acid Synthesis Inhibitors; D003609:Dactinomycin; D012313:RNA; D012964:Sodium