The hypothesis that subsatiating levels of internal food stimuli can arouse and potentiate feeding behavior was examined in the mollusc Aplysia californica. Animals were fed a small quantity of seaweed and their latencies to show biting responses were determined after food arousal was permitted to partially decay. Control animals were stimulated with food, but were not permitted to ingest it, or were fed nonnutritive glass-fiber filter paper. Compared to controls, animals that were fed showed significantly shorter latencies to respond when tested up to 80 min after previous exposure to food. These results indicate that internal stimuli can function like external stimuli to enhance responsiveness to food and suggest the hypothesis that satiation may be viewed as an interactive process involving the interplay of excitatory and inhibitory influences arising from the alimentary system.
Bibliographical noteFunding Information:
We thank M. Schwarz, E. Feldman, and B. Ollech for comments on the manuscript. This work was supported, in part, by U.S.-Israel Binational Science Foundation Grant 2210, by National Institutes of Health Grants RO1 MH35564, RO1 MH36730, and GM 32099, and by Research Scientist Development Award 1KO2 MH00304 to Klaudiusz R. Weiss.