Protein kinase C mediates memory consolidation of taste avoidance conditioning in Lymnaea stagnalis

• Published in: Neurobiology of learning and memory 2014-05, Vol.111, p.9-18
• Main Authors: Takigami, Satoshi, Sunada, Hiroshi, Lukowiak, Ken, Kuzirian, Alan M., Alkon, Daniel L., Sakakibara, Manabu
• Format: Article
• Language: English
• Subjects: Animal cognition; Animal memory; Animals; Avoidance Learning - drug effects; Avoidance Learning - physiology; Behavioral psychophysiology; Biological and medical sciences; Bryostatin; Bryostatins - pharmacology; Conditioning (Psychology) - drug effects; Conditioning (Psychology) - physiology; Fundamental and applied biological sciences. Psychology; Kinases; Long-term memory; Lymnaea; Lymnaea stagnalis; Memory - drug effects; Memory - physiology; Memory consolidation; Mollusks; Neurobiology; Protein kinase C; Protein Kinase C - drug effects; Protein Kinase C - metabolism; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Ro-32-0432; Short-term memory; Taste - physiology; Taste avoidance conditioning
• ISSN: 1074-7427; 1095-9564
• DOI: 10.1016/j.nlm.2014.02.011

•The critical role of PKC activation for memory enhancement was examined.•Twenty paired CS–US presentations resulted in STM and LTM.•Pre-exposure to PKC activator formed STM with 5 paired CS–US presentations.•Pre-incubation with PKC activator facilitated STM into LTM.•Pre-incubation with PKC inhibitor failed to form both STM and LTM. In Lymnaea stagnalis, in order to obtain a 10min short-term memory (STM) of taste avoidance conditioning (TAC) at least 10 paired presentations of a conditioned stimulus (CS), sucrose, and an unconditioned stimulus (US), tactile stimulation to the animal’s head, are required. Pre-exposure of snails to the protein kinase C (PKC) α and ε activator bryostatin (Bryo) facilitated STM formation in that only 5 paired CS–US trials were required. Typically 20 paired presentations of the CS–US are required for formation of STM and LTM. However, 20 paired presentations do not result in STM or LTM if snails are pre-incubated with a PKC inhibitor, Ro-32-0432. We also found that LTM lasting longer than 48h was acquired with Bryo incubation for 45min even after termination of the conditioning paradigm. These data suggest that activation of the α and ε isozymes of PKC is crucially involved in the formation of LTM and provide further support for a mechanism that has been conserved across the evolution of species ranging from invertebrate molluscs to higher mammals.