AJP - Regulatory, Integrative and Comparative Physiology, Vol 257, Issue 5 1075-R1082, Copyright © 1989 by American Physiological Society
Response to palatability after area postrema lesions: a result of learned aversions
N. Tomoyasu and N. J. Kenney
Department of Psychology, University of Washington, Seattle 98195.
The role of palatability, novelty, and food aversion in determining changes
of food choice after ablation of the area postrema and caudal-medial aspect
of the nucleus of the solitary tract (AP/cmNTS) is examined through a
series of studies utilizing 24-h, two-food choice tests. On test days, the
food that the animal has ingested since the time of lesioning or sham
surgery is presented along with a novel food that varies in palatability.
The results indicate that postlesion diet history is the major determinant
of food choice by lesioned rats. Lesioned rats consistently take less of
their familiar postlesion food than diet-matched controls, suggesting that
the lesioned rats have developed an aversion to that food. Over-ingestion
of the novel food may occur, but this outcome is not reliable. No
indication that the animals' response to food palatability is affected by
AP/cmNTS ablation was found. Learned aversion to a food ingested after
AP/cmNTS ablation may account not only for changes of food preference after
the lesion but also may be involved in the hypophagia and weight loss
resulting from the ablation.
