PARTIAL ANATOMICAL AND PHYSIOLOGICAL CHARACTERIZATION AND DISSOCIATEDCELL-CULTURE OF THE NERVOUS-SYSTEM OF THE MARINE MOLLUSK APLYSIA-KURODAI

Snail nervous systems are powerful tools for neurobiological studies a s the biophysical properties of the giant neurons and their neural cir cuits can be examined in relation to specific behaviors of animals. Th e marine mollusc Aplysia californica is particularly useful for analyz ing the components of learning and memory at the molecular and cellula r levels. Here we partially examined the nervous systems of two specie s (A. kurodai and A. juliana) commonly found along the Korean coast in comparison with that of A. californica, one of the American marine sn ails. A. kurodai appeared to be identical to A. californica in both an atomical and physiological properties of the nervous system. A. julian a could be distinguished from A. californica in certain morphological aspects of the nervous system. The hemolymph either from A. kurodai or from A. juliana was required for effectively elongating neurite outgr owth of A. kurodai neurons in dissociated cell culture. The cultured c ells retained neuronal properties such as neurite outgrowth, synapse f ormation, and generation of action potentials. The sensory cells of A. kurodai in dissociated cultures showed a response to serotonin (5-HT) of spike broadening and enhanced membrane excitability as in intact g anglia. Therefore, the nervous system and dissociated neuronal culture of A. kurodai may be useful for studying learning and memory in the c ontext of well-defined neural circuits of A. californica.