Quinine monohydrochloride - CAS 130-89-2

1. The responses of 126 neurons in primary gustatory cortices of two rhesus monkeys were recorded during sapid stimulation of the tongue with 18 taste stimuli. Ten of these stimuli were dissolved in distilled water (DW): 1.0 M sucrose (Suc), 0.1 M and 0.03 M sodium chloride (NaCl), 0.003 M hydrochloric acid (HCl), 0.001 M quinine hydrochloride (QHCl), 0.03 M monosodium glutamate (MSG), 0.03 M polycose, 0.3 M glycine, 0.1 M proline, and 0.1 M malic acid. Seven other stimuli were dissolved in 0.03 M MSG; the last stimulus was a mixture of 1.0 M Suc and 0.03 M NaCl. 2. The average spontaneous rate (2.2 +/- 0.2 spikes/s, mean +/- SE) and response to DW (2.5 +/- 0.2) of these 126 neurons was low but within the range previously reported for neurons in primate taste cortex. Suc was the most effective stimulus for 24.1% of the neurons tested followed by NaCl (15.7%), QHCl (14.8%), HCl (11.1%), MSG (10.2%), and other miscellaneous unitary gustatory stimuli (8.3%). Binary taste mixtures were the most effective stimuli for 15.7% of the sample. The net responses (corrected for DW, in spikes/s) for Suc-best (3.3), NaCl-best (4.3), HCl-best (3.4), QHCl-best (2.3), and MSG-best (4.1) were sluggish, but comparable with that reported previously.

The present study evaluates the effect of hyperbaric oxygen therapy on taste sensitivity, hedonic perception of taste, and food preferences. The studied groups included 197 people in total (79 in the study group; 118 in the control group). All patients from the study group were treated with hyperbaric oxygen therapy due to chronic non-healing wounds. The control group consisted of healthy people, who did not receive hyperbaric oxygen therapy. The taste intensity, recognition thresholds, and hedonic perception were examined using gustatory tests. The aqueous solutions of sucrose for sweet, sodium chloride for salty, citric acid for sour, quinine hydrochloride for bitter, and monosodium glutamate for umami taste were used. The participants fulfilled the questionnaire to examine pleasure derived from eating certain types of dishes. Gustatory tests and analyses of the pleasure derived from eating in the study group were carried out before the first exposure to hyperbaric oxygen and then at the end of therapy, after at least 25 sessions of treatment. In the control group, examination of perception of taste sensations was conducted only once. The results of comparing patients with non-healing wounds with healthy people are characterized by reduced taste sensitivity.

PURPOSE: ;The purpose of this study was to examine the usefulness of a new gustatory test based on the progress of mastication by counting the number of chewing strokes required for recognizing tastes.;METHODS: ;Thirty-nine subjects (20 males and 19 females, 25.3±6.4 years old) without missing teeth were selected. Four types of newly designed test materials made from 15% gelatine were prepared, containing sucrose, sodium chloride, tartaric acid, or quinine hydrochloride. Five or six concentrations, representing weak to strong tastes, were prepared for each tastant. Subjects were instructed to chew the food, and the number of chewing strokes necessary to recognize the taste was counted.;RESULTS: ;Female subjects recognized the sweet taste more accurately than male subjects (Friedman test: p<0.05). For each tastant of the test materials, the average number of chewing strokes (recognition threshold) was approximately 10. The frequency of correct responses and the average number of chewing strokes tended to be higher and lower, respectively, as the concentration of the taste in the test material increased (Kruskal-Wallis test: sweet p<0.01, salty p<0.01, sour p<0.01 and bitter p<0.01).;CONCLUSIONS: ;Using the newly designed test materials, counting the number of chewing strokes necessary for recognizing the taste would be a useful index of a new gustatory test to investigate taste sensation.