Effects of selective adaptation on coding sugar and salt tastes in mixtures.

Little is known about coding of taste mixtures in complex dynamic stimulus environments. A protocol developed for odor stimuli was used to test whether rapid selective adaptation extracted sugar and salt component tastes from mixtures as it did component odors. Seventeen human subjects identified taste components of "salt + sugar" mixtures.

Amiloride-sensitive and amiloride-insensitive responses to NaCl + acid mixtures in hamster chorda tympani nerve.

Component signaling in taste mixtures containing both beneficial and dangerous chemicals depends on peripheral processing. Unidirectional mixture suppression of chorda tympani (CT) nerve responses to sucrose by quinine and acid is documented for golden hamsters (Mesocricetus auratus). To investigate mixtures of NaCl and acids, we recorded multifiber responses to 50 mM NaCl, 1 and 3 mM citric acid and acetic acid, 250 μM citric acid, 20 mM acetic acid, and all binary combinations of each acid with NaCl (with and without 30 μM amiloride added).

B6-MSM consomic mouse strains reveal multiple loci for genetic variation in sucrose octaacetate aversion.

Based on crosses among inbred strains derived principally from M. m. domesticus, sucrose octaacetate (SOA) aversion in laboratory mice has been thought for many years to be controlled by a single genetic locus (Soa) located on distal chromosome (Chr) 6.

Responses of the hamster chorda tympani nerve to sucrose+acid and sucrose+citrate taste mixtures.

Studies of taste receptor cells, chorda tympani (CT) neurons, and brainstem neurons show stimulus interactions in the form of inhibition or enhancement of the effectiveness of sucrose when mixed with acids or citrate salts, respectively. To investigate further the effects of acids and the trivalent citrate anion on sucrose responses in hamsters (Mesocricetus auratus), we recorded multifiber CT responses to 100 mM sucrose; a concentration series of HCl, citric acid, acetic acid, sodium citrate (with and without amiloride added), potassium citrate, and all binary combinations of acids and salts with 100 mM sucrose. Compared with response additivity, sucrose responses were increasingly suppressed in acid + sucrose mixtures with increases in titratable acidity, but HCl and citric acid were more effective suppressors than acetic acid.

Cycloheximide: no ordinary bitter stimulus.

Cycloheximide (CyX), a toxic antibiotic with a unique chemical structure generated by the actinomycete, Streptomyces griseus, has emerged as a primary focus of studies on mammalian bitter taste. Rats and mice avoid it at concentrations well below the thresholds for most bitter stimuli and T2R G-protein-coupled receptors specific for CyX with appropriate sensitivity are identified for those species. Like mouse and rat, golden hamsters, Mesocricetus auratus, also detected and rejected micromolar levels of CyX, although 1mM CyX failed to activate the hamster chorda tympani nerve.

Peripheral gustatory processing of sweet stimuli by golden hamsters.

Behaviors and taste-nerve responses to bitter stimuli are linked to compounds that bind T2 receptors expressed in one subset of taste-bud receptor cells (TRCs); and behavioral and neural responses to sweet stimuli are linked to chemical compounds that bind a T1 receptor expressed in a different TRC subset. Neural and behavioral responses to bitter-sweet mixtures, however, complicate the ostensible bitter and sweet labeled lines. In the golden hamster, Mesocricetus auratus, quinine hydrochloride, the bitter prototype, suppresses chorda tympani (CT) nerve responses to the sweet prototype: sucrose.

Responses of the rat chorda tympani nerve to glutamate-sucrose mixtures.

Monosodium glutamate (MSG) has a multifaceted, unusual taste to humans. Rats and other rodents also detect a complex taste to MSG. Responses of the chorda tympani nerve (CT) to glutamate applied to the front of the tongue were recorded in 13 anesthetized rats.

Taste responses to mixtures: analytic processing of quality.

The tastes of 100 mM sodium chloride (NaCl), 100 mM sucrose, and 1 mM quinine hydrochloride in mixtures were investigated in golden hamsters (Mesocricetus auratus) with a conditioned taste aversion (CTA) paradigm. CTAs, established in golden hamsters by injection of lithium chloride, were quantified as percent suppression of control 1-hr stimulus intake. CTAs for 10 of 15 stimulus pairs with common components symmetrically cross-generalized, suggesting that component qualities were recognized in binary and ternary mixtures.

Taste function in patients with oral burning.

Burning mouth syndrome (BMS) is an oral pain disorder occurring primarily in post-menopausal women and is frequently accompanied by taste complaints. This association of symptoms suggests an interaction between the mechanisms of nociception and gustation, two senses with strong hedonic components. Seventy-three patients of the Taste and Smell Clinic at the University of Connecticut Health Center who reported experiencing 'unexplained oral burning' were evaluated for taste function.

The effects of topical anesthesia on oral burning in burning mouth syndrome.

Burning mouth syndrome (BMS) is an oral pain disorder of uncertain origin. Central or peripheral pain mechanisms may play a role in the oral burning of BMS. We tested the effect of a topical anesthetic (dyclonine HCl) on patients' intensity ratings for oral burning, taste dysgeusia and the taste of two chemical stimuli (1.

The taste of polycose in hamsters.

Hamsters show a preference for Polycose, a mixture of starch-derived glucose polymers, that is as strong as their preference for sucrose. However, in the hamster, taste aversions to Polycose may be less easily acquired than taste aversions to sucrose and the qualitative aspects of Polycose are unknown in this species. In order to examine the taste of Polycose in the hamster, we utilized a taste-aversion protocol with two conditioning trials.

Opponent effects of quinine and sucrose on single fiber taste responses of the chorda tympani nerve.

Responses of single chorda tympani fibers to mixtures of taste stimuli were studied in the golden hamster (Mesocricetus auratus). Sucrose-best neurons showed significant suppression to quinine-sucrose mixtures compared to sucrose alone. Quinine may exert its effect as an opponent stimulus in the receptor cells at the second messenger level.

Responses of the hamster chorda tympani nerve to binary component taste stimuli: evidence for peripheral gustatory mixture interactions.

Studies of taste mixtures suggest that stimuli which elicit different perceptual taste qualities physiologically interact in the gustatory system and thus, are not independently processed. The present study addressed the role of the peripheral gustatory system in these physiological interactions by measuring the effects of three heterogeneous taste mixtures on responses of the chorda tympani (CT) nerve in the hamster (Mesocricetus auratus). Binary taste stimuli were presented to the anterior tongue and multi-fiber neural responses were recorded from the whole CT.

Lack of amiloride sensitivity in SHR and WKY glossopharyngeal taste responses to NaCl.

To explore possible functional strain differences in taste receptors located on the posterior tongue, we recorded electrophysiological taste responses from the glossopharyngeal nerve of spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) rats. Multifiber responses to a concentration series (0.5 M to 2.

Perceptual characteristics of the amiloride-suppressed sodium chloride taste response in the rat.

The contribution of amiloride-sensitive membrane components to the perception of NaCl taste was assessed by using a conditioned taste aversion procedure. Eight independent groups of adult rats were conditioned to avoid either 0.1M NaCl, 0.

Peripheral taste responses in genetically hypertensive rats.

In two-bottle preference-aversion tests, the spontaneously hypertensive rat (SHR) tolerates higher concentrations of NaCl than the normotensive Wistar-Kyoto (WKY). In contrast, the inbred Dahl salt-sensitive (S/JR) and inbred Dahl salt-resistant (R/JR) rat show similar preferences for NaCl. In order to determine if taste receptor function was also altered between the hypertensive rat and its normotensive control, we recorded electrophysiological taste responses from the chorda tympani (CT) nerve in SHR, WKY, S/JR and R/JR rats.

Alterations of salt taste perception in the developing rat.

Behavioral correlates of changing neurophysiological taste sensitivities during development were assessed with a conditioned taste aversion procedure. Young rats (age 25-30 days) avoided 0.1M monochloride salts and 1.

An analysis of residual NaCl taste response after amiloride.

The identity of the residual taste response to NaCl after lingual application of the sodium transport blocker, amiloride, was studied by electrophysiological recordings from the rat chorda tympani nerve. Stimulation of the anterior tongue with salt solutions resulted in responses to halogenated sodium salts that were not eliminated by amiloride; approximately 30% of the halogenated sodium salt response remained after amiloride. In contrast, responses to nonhalogenated sodium salts were reduced to less than 4% of the original response after amiloride.