Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Taste Threshold”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 577 records · Page 32Linked to original sources
PubMed1982

Gustatory neural response in the mouse.

Gustatory responses from the mouse chorda tympani nerve were tested with various chemical solutions. Magnitudes of integrated chorda tympani responses to the 4 basic taste stimuli were greater in the order of HCl, sucrose, NaCl and quinine-HCl. Sucrose was the most effective sugar tested, while NaCl was the least effective salt, but divalent chloride salts were prominently effective stimulants. Many of single chorda tympani fibers responded specifically to one or two of the 4 basic taste stimuli. Single fibers sampled were classified into the following 5 types: sweet-type, Na-type, Ca-Mg-type, acid-type and quinine-type.

Animals↗
PubMed1982

Amino acids as taste stimuli. II. Quality coding.

Two experiments were performed in rats to evaluate the relative taste qualities of 12 L-amino acids, each at a concentration which evoked half the maximum response for that chemical. The first study involved recording the activity of 40 individual chorda tympani fibers to the stimulus series. Only 34% of the evoked responses resembled the short latency phasic-tonic activity which characterizes gustatory responses to inorganic salts and acids. 32% had latencies exceeding 1 s; another 27% consisted of only a phasic burst lasting less than 1 s. The remaining 7% were inhibitory. Both long latency and purely phasic activity were stimulus selective: 61% of the former were in response to Gly or Pro while 69% of the latter were evoked by Cys-HCl, Lys-HCl or His. Response inhibition was not associated with either specific fibers or stimuli. Thus amino acids, which to humans represent a class of perceptually complex stimuli, show a corresponding complexity of evoked neural properties in the rat. The second study employed a conditioned taste aversion paradigm to assess the qualitative similarity of each amino acid to the others and to the 4 prototypical taste stimuli; NaCl, HCl, quinine-HCl and sucrose. Some amino acids showed strong generalization to a single gustatory prototype (Pro and Gly to sucrose; Cys-HCl to HCl); others generalized well to multiple prototypes (e.g. Arg to sucrose and NaCl). Several showed poor generalization to all 4 prototypical tastes, calling into question the assumption that these 4 totally encompass the gustatory domain.

Animals↗
PubMed1983

Mechanism of the water response in carp gustatory receptors: independent generation of the water response from the salt response.

The carp gustatory responses to various salts and those to distilled water after adaptation of the receptors to the salts were recorded from the palatine nerve under varying conditions. (a) As far as Na4Fe(CN)6 solution prepared freshly was used, any peak in the dose-response curve was not observed, while the solution stored overnight induced a large peak response at the low concentration region as Konishi reported. The magnitude of the water response after adaptation to the stored solution was practically equal to that after adaptation to the fresh solution, suggesting that the receptor site for the water response is different from that for the dilute salts. (b) The responses to salts depended largely on the species of both cations and anions of the salts. The responses were deceased with an increase in the lyotropic number of the anions and increased with an increase in the number above 11. The response to distilled water was practically independent of the species of both monovalent cations and anions of the salts used for the adaptation. The pH dependence of the response to 10 mM NaCl was largely different from that to distilled water after adaptation to 10 mM NaCl. (c) The water response was suppressed by the presence of electrolytes in stimulating solution; the data obtained with different species of salts were described by a single curve as a function of the ionic strength. (d) The mechanism to explain how distilled water leads to depolarization of the taste cell was discussed in terms of the electric double-layer potential.

Animals↗
PubMed1986

Synergistic effects of 5'-nucleotides on rat taste responses to various amino acids.

Synergism between 5'-nucleotides and L-amino acids in the rat taste nerve responses was investigated. The synergism was examined between low concentration of the nucleotides which induce only a negligibly small response and various concentrations of amino acids. A marked synergism was found between 5'-nucleotides and all the amino acids examined. Purine 5'-nucleotides such as GMP, deoxy GMP, GDP, GTP, AMP or IMP exhibited the synergistic effect on the responses to amino acids, while pyrimidine 5'-nucleotides such as CMP or UMP exhibited practically no synergistic effect. The presence of GMP led to a shift of the concentration-response curves for amino acids to a lower concentration region without affecting the response of the saturation level. These curves were analyzed under the assumption that there exist two types of receptor sites with different dissociation constants for each amino acid. The results suggest that GMP leads to a decrease in dissociation constants, especially for high affinity sites without affecting maximal responses. Monosodium glutamate (Glu) itself, which is known as a typical 'flavor potentiator', exhibited no enhancing effect on the responses to 4 primary taste stimuli. The mechanism of how Glu and the 5'-nucleotides 'potentiate' flavor of food is discussed.

Amino Acids↗
PubMed1988

Reduced saccharin preference in CXBK (opioid receptor-deficient) mice.

The preference for sweet solutions in opioid receptor-deficient (CXBK) and control (C57BL/6By) mice was compared. CXBK and C57BL/6By (C57) mice were presented for 2 h/day with 2 tubes, one always containing water and the other containing either water or various concentrations of saccharin solution. Fifteen minutes before the drinking session, half of the mice in each strain were injected with naltrexone (0.2 mg/kg) and the other half with saline. Compared to C57 mice, CXBK mice had significantly lower saccharin preference. Naltrexone reduced the saccharin preference in both strains, almost completely abolishing preference in CXBK mice. The results support the hypothesis that brain opioid receptors are involved in mediating sweet palatability and suggest that genetic differences in opioid receptor density contribute to differences in the palatability of sweet solutions.

Animals↗
PubMed1988

Ionic mechanism of generation of receptor potential in response to quinine in frog taste cell.

The ionic mechanism of generation of the receptor potential in a frog taste cell elicited by quinine-HCl (Q-HCl) was studied with an intracellular recording technique by replacing the superficial and interstitial fluids of the tongue with various saline solutions. The taste cells whose receptor membranes were adapted to normal saline and deionized water generated depolarizing receptor potentials at Q-HCl concentrations higher than 2 and 0.01 mM, respectively. The input resistance of taste cell during Q-HCl stimulation scarcely changed. The receptor potential did not change even when the membrane potential level was broadly changed. The magnitude of the receptor potential was increased by reducing the concentration of superficial Cl- on the taste receptor membrane, but was independent to the concentration of superficial Na+. Injection of Cl- into a taste cell increased the receptor potential to 170%. The magnitude of receptor potential was decreased to 20-30% by removing interstitial Na+ or Cl- or both surrounding the basolateral membrane of taste cell. Furosemide (1 mM) added to the interstitial fluid decreased the receptor potential to 15%, while interstitial ouabain (0.1 mM) and superficial SITS (0.1 mM) did not influence it. From these results, we conclude: (1) an electroneutral Na+/Cl- cotransport occurs through the basolateral membrane of a taste cell in the resting state, so that Cl- accumulates inside the cell. (2) Q-HCl stimulation induces the active secretion of Cl- across the taste receptor membrane, resulting in a depolarizing receptor potential.

Action Potentials↗
PubMed1995

c-Fos induction in response to taste stimuli previously paired with amphetamine or LiCl during taste aversion learning.

Amphetamine and lithium chloride (LiCl) are both effective unconditioned stimuli (USs) in the establishment of conditioned taste aversions (CTA) in the rat. However, the mechanism of action of these drugs is quite different with the area postrema and related emetic circuitry critical to the response to LiCl but not amphetamine. c-Fos immunohistochemistry was used to define brain regions activated during drug administration and during expression of a CTA using either amphetamine or LiCl as the US drug. Administration of LiCl induced dense c-Fos-like immunoreactivity (c-FLI) in the nucleus of the solitary tract (NTS) while amphetamine induced only light staining in this area. A conditioned stimulus (CS) saccharin solution paired with amphetamine, however, was associated with c-FLI in NTS in a pattern quite similar to that seen to a LiCl-paired CS. This suggests that the pattern of c-Fos expression to a taste CS after conditioning is characteristic of aversion conditioning, in general, and appears not to represent a matching of the conditioned response to specific unconditioned effects of the drug. To examine this conditioned response further, c-FLI to the aversive saccharin CS was compared to the response to quinine hydrochloride, which is innately aversive. Although behaviorally the animals' ingestive responses were quite similar, the saccharin CS induced significant elevations of c-FLI in NTS whereas the quinine did not. Thus, a taste which had become aversive by virtue of conditioning induced c-FLI expression in NTS while a taste which was inherently aversive did not.

Amphetamine↗
PubMed1984

Salt taste and hypertension: a critical review of the literature.

Studies of the salt taste sensitivity, responsiveness, preference, and appetite of normotensive and hypertensive individuals have yielded therapeutic, diagnostic, predictive, and mechanistic findings related to hypertension. Following a brief description of the nature of these taste parameters, findings pertaining to the association between each and hypertension are critically reviewed. Potential clinical implications of this information, as well as the need to exercise caution in the translation of taste data into dietary practice are also discussed.

Adolescent↗
PubMed1975

Effect of gonadectomy on taste preference for glucose solutions in rats.

Mature male and female rats maintained on an ad lib diet were given a choice between tap water and glucose solutions of different concentrations (1, 5 and 12 percent). Both sexes exhibited a definite preference for the 12 percent glucose solution, but the females drank significantly more than males. Gonadectomy produced neither quantitative nor qualitative changes in the choice made by male rats. On the contrary, gonadectomized females showed a depression of the 12 percent glucose solution intake and an increase in the 5 percent glucose solution intake, resulting in a decrease of the total fluid intake. A comparison of ovariectomized and intact female rats in regard to the self-selection of tap water and a 5 percent glucose solution confirmed the stimulatory effect of ovariectomy on the 5 percent glucose solution intake. When a choice between tap water and 12 percent glucose solution was permitted the ovariectomized rats showed a weaker positive response to the sweet solution than the intact female rats.

Animals↗
PubMed1977

Taste and olfaction in human obesity.

Earlier studies have shown differences between normal weight and obese humans in responsivity to external and internal stimuli. This study shows that normal weight and obese subjects do not differ in hedonic response to sucrose (taste) and benzaldehyde (odor). However, a perceptual typing of individuals based upon hedonic response is possible for both gustatory and olfactory processes. Ratings of pleasantness for the sweet taste of sucrose appear to generalize to the food-related odor of bitter almonds. The method of magnitude estimation as applied to the study of taste and olfaction in man may reveal relationship between changes in internal state and hedonic behavior.

Adult↗