Development of an in vitro analog concomitantly expressing the cellular correlates of sensitization and suppression of feeding in Aplysia californica

Abstract

When presented with aversive stimuli, the marine mollusk Aplysia californica shows increased defensive responses (sensitization) and suppression of feeding. The cellular correlates of sensitization and suppression of feeding include increased excitability of the tail sensory neurons (TSNs, which mediate defensive responses) and decreased excitability in neuron B51 (a cell critical to the Aplysia feeding circuit), respectively. The goal of this project was to develop a reduced preparation of the isolated Aplysia nervous system (buccal, pleural‐pedal, and cerebral ganglia) in which the effects of aversive stimuli within the defense and feeding neural circuits could be mimicked in vitro by electrical stimulation of afferent nerves. We successfully observed significant concomitant increase in excitability of the TSNs (measured by spikes evoked) and decrease in excitability of B51 (increase in the burst threshold) 15 min post stimulation. Currently, we are examining whether this in vitro analog expresses long term (24 h) correlates. This in vitro analog will facilitate further analyses of cellular and molecular modifications resulting from aversive stimulation, as it would allow manipulations not feasible in vivo. Supported by NSF Grant IOS 1120304 to RM.