Behavioral bitter taste

The bitter taste is therefore reported by occasional and accidental tasting or by the observation of rejection behavior by animals. The equation alkaloid atoxic = bitter is so strong that sometimes the presence of some bitter alkaloids was assumed in some bitter plants and never demonstrated by the isolation of any active principle of bitter taste. It is worth noting that many toxic alkaloids are reported as bitter not only in the popular tradition but in scientific literature. Table 3.2 lists some of these compounds, reporting the common name, CAS number and if the compound is listed on Toxnet. 

Dotson CD, Roper SD, Spector AC (2005) PLCbeta2-independent behavioral avoidance of prototypical bitter-tasting ligands. Chem Senses 30 593-600 Farbman AI (1980) Renewal of taste bud cells in rat circumvallate papillae. Cell Tissue Kinet 13 349-357... 

Some acids (e.g., acetic and citric) have a sour taste. In fact, sourness had been a defining property since the 17 " century an acid was any substance that had a sour taste reacted with active metals, such as aluminum and zinc, to produce hydrogen gas and turned certain organic compounds characteristic colors. (We discuss indicators later and in Chapter 19.) A base was any substance that had a bitter taste and slippery feel and turned the same organic compounds different characteristic colors. (Please remember NEVER to taste or touch laboratory chemicals instead, try some acetic acid in the form of vinegar on your next salad.) Moreover, it was known that when acids and bases react, each cancels the properties of the other in a process called neutralization. But definitions in science evolve because, as descriptions become too limited, they must be replaced by broader ones. Although the early definitions of acids and bases described distinctive properties, they inevitably gave way to definitions based on molecular behavior. 

Vinnikov (3.) concludes the taste of salts depends on the cation and anion, sour or acid stimulus of the hydrogen ion, sweet and bitter on Intramolecular shifts of protein receptors and gustatory substance complexes. He approaches the problem from a molecular basis of both substance and receptor. Exact behavior to taste has covered mostly feeding and reproduction in this paper and much more field and laboratory research is needed on specific animal species. 

Taste is very species dependent euid seldom is predictable based on the eiq>erlences and preferences of man. While we classify our tastes as sweet, sour, bitter and salty, einimal behaviors in relation to taste are better described as evidence of preferences, aversions, or Indifference (19). In studies with cattle, sheep emd normal emd pygmy goats with solutions representative of the four classical tastes, cattle discriminated sweet, salty emd sour tastes at lower concentrations than the other species. Cattle, however, showed the poorest discriminating behavior with bitter tastes and also tolerated the bitter taste at the greatest intensity (20). 

Noble, A.C., Astringency and bitterness of flavonoid phenols. In Chemistry of Taste Mechanisms, Behaviors, and Mimics (eds P. Given and D. Paredes), American Chemical Society, Washington, DC, 2002, p. 192. 

Table II. Tasting Behavior of Combination of Typical Bitter Compounds and Acetic Acid ------------------------------------5------------...

Taste Behavior in Mixed Sweet and Bitter Solutions. 

Table V. Tasting Behavior of Combination of Typical Bitter Compounds and Benzoyl-e-aminocoproic acid...

Benzoyl-e-aminocaproic acid-bitter compound mixtures, tasting behavior, 33,34f... 

Bitter-sweet solution mixtures, taste behavior, 32-34f... 

Bottle choice. A widely used method for quantitatively monitoring rodent behavior with regard to taste is the bottle-choice assay. An animal is placed in a cage with two water bottles, one of which contains a potential tastant. After a fixed period of time (24-48 hours), the amount of water remaining in each bottle is measured. Suppose that much less water remains in the bottle with the tastant after 48 hours. Do you suspect the tastant to be sweet or bitter ... 

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