Feeding is largely guided by the sense of taste. it is now established that this influence is reciprocal: taste sensitivity is, to some degree dependent upon what has been eaten. This conclusion rests on the recognition of three emerging facts: (1) Taste-evoked activity is primarily devoted to encoding stimulus nutrition vs toxicity, a measure which parallels acceptance vs rejection behavior in rats and positive vs negative appreciation in humans. Thus, taste input carries information on the physiological value of a potential food, and it is on the basis of this information that feeding and the pleasure derived from it are determined. (2) Taste-evoked activity, in turn, is subject to modification according to the past experience or the momentary physiological needs of the organism. Thus, biochemical needs can influence the very taste input which guides feeding. The reciprocal interaction between taste and physiological condition presents a likely neural mechanism for the notion of body widsom. (3) This interaction takes place largely at the hindbrain level. The anatomical convergence through which such an interplay could function occurs in the hindbrain. Organisms with only the caudal brainstem intact respond appropriately to the nutritional vs toxicity dimension of taste, and change that reaction to meet many of the transient needs of the body. Several endogenous chemicals which affect feeding behavior have recently been identified. There is a widespread recognition that sensory influences, particularly those of taste, may be involved in mediating their actions.
The aim of this proposed series of studies is to test that assumption directly. Taste-evoked responses will be recorded from single cells in the rat nucleus tractus solitarius before and after intravenous administration of each of six chemical factors which have been shown to influence feeding. If no changes in gustatory responsiveness occur with the manipulation, taste will be eliminated as a possible mechanism through which these substances might alter intake. More likely, taste activity will be affected. Such a finding would bear on two issues: (1) It would provide a specific mechanism through which the administered satiety factor might work and also strengthen the general notion of sensory-ingestive integration in the hindbrain. (2) It would address controversies of neural coding in taste, particularly the existence of gustatory neuron types.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
2R01DK030964-07
Application #
3229755
Study Section
Biopsychology Study Section (BPO)
Project Start
1982-08-01
Project End
1993-03-31
Budget Start
1990-04-01
Budget End
1991-03-31
Support Year
7
Fiscal Year
1990
Total Cost
Indirect Cost
Name
University of Delaware
Department
Type
Schools of Arts and Sciences
DUNS #
059007500
City
Newark
State
DE
Country
United States
Zip Code
19716
Giza, B K; Ackroff, K; McCaughey, S A et al. (1997) Preference conditioning alters taste responses in the nucleus of the solitary tract of the rat. Am J Physiol 273:R1230-40
McCaughey, S A; Giza, B K; Scott, T R (1996) Activity in rat nucleus tractus solitarius after recovery from sodium deprivation. Physiol Behav 60:501-6
Giza, B K; McCaughey, S A; Zhang, L et al. (1996) Taste responses in the nucleus of the solitary tract in saccharin-preferring and saccharin-averse rats. Chem Senses 21:147-57
Giza, B K; Deems, R O; Vanderweele, D A et al. (1993) Pancreatic glucagon suppresses gustatory responsiveness to glucose. Am J Physiol 265:R1231-7
Giza, B K; Scott, T R; Vanderweele, D A (1992) Administration of satiety factors and gustatory responsiveness in the nucleus tractus solitarius of the rat. Brain Res Bull 28:637-9
Giza, B K; Scott, T R (1991) The effect of amiloride on taste-evoked activity in the nucleus tractus solitarius of the rat. Brain Res 550:247-56
Giza, B K; Scott, T R; Sclafani, A et al. (1991) Polysaccharides as taste stimuli: their effect in the nucleus tractus solitarius of the rat. Brain Res 555:1-9
Scott, T R; Giza, B K (1990) Coding channels in the taste system of the rat. Science 249:1585-7
Giza, B K; Scott, T R; Antonucci, R F (1990) Effect of cholecystokinin on taste responsiveness in rats. Am J Physiol 258:R1371-9