© 1972 by The Society for Integrative and Comparative Biology
Behavioral and Electrophysiological Studies on Chemoreception in Aplysia
Department of Biology, Clark University Worcester Massachusetts 01610
Using the typical mouth opening response (MOR) as the index of chemore-ception, several amino acid constituents of natural food for Aplysia were effective in eliciting MOR in concentrations as low is 106 107 M (glutamic acid) and 105 106 M (aspartic acid). It was suggested that these substances may serve as food attractants for this animal. Combined results of behavioral and electrophysiological experiments indicated that the most sensitive food receptors of Aplysia are predominantly located in the anterior tentacular groove area of the oral veil. These receptors appeared to strongly project to the caudal dark cell clusters of the cerebral ganglion. Extracellular recording of single afferent units following oral veil stimulation with various chemicals showed that the chemoreceptors in the anterior tentacular groove area were 100 to 1000 times more sensitive to food substances than other stimuli tested. It was suggested that these receptors are relatively "specific" to food attractants. There was a correlation between behavioral and electrophysiological threshold data for the individual compounds. The electrophysiological thresholds however were 515 times higher than the behavioral thresholds.