Project: Research project

Project Details


DESCRIPTION (from applicant's abstract): Gustatory stimuli, particularly those
that taste sweet to humans, initiate and maintain ingestive behavior. They also
provide reward sufficient to support the learned behavior used by most animals
to locate food. Reward mechanisms related to feeding (and other biological
drives) have been linked to the mesolimbic dopamine (DA) system in general, and
to the nucleus accumbens, specifically. Nevertheless, the function of accumbens
DA in reward remains unclear. Taste provides a logical tool for examining
central reward mechanisms. Sapid chemicals are quantified easily, they are
transduced via a single, well-described sensory channel, and they can be
disassociated from their nutritional consequences. Conversely, such testing of
the central reward systems can shed light on a central conundrum of gustatory
physiology -how the hedonic qualities of tastes can be reconciled with their
purely sensory characteristics. Despite the substantial overlap between taste
and reward, relatively little experimental attention has been focused on the
interaction of these systems at the neural level. The present experiments are
designed to: 1) investigate whether sapid sucrose activates the mesoaccumbens DA
neurons in a concentration dependent manner during sham feeding; 2) evaluate the
effect sucrose licking on NAc DA during chronic weight reduction, as a model of
reward sensitization; and 3) examine the contributions of DI and D2 dopaminergic
mechanisms of the NAc in the mediation of both the behavioral and neurochemical
activation related to sucrose ingestion in both normal and underweight rats.
Unlike previous sham-feeding studies that used systemic injections, dopaminergic
drugs will be perfused locally in the NAc through reverse microdialysis. The
long-term objective of such an investigation is to understand how food-related
oral stimuli produce reward. This knowledge is directly relevant to
understanding the control of normal ingestive behavior and to the maladies
related to this essential behavior, such as obesity, anorexia nervosa, bulimia
nervosa, and binge eating disorder.
Effective start/end date1/1/0112/31/03