Papers by Corinne Ossebaard
Springer eBooks, 1994
Peripheral and central spatial summation and mixture suppression in taste were investigated by th... more Peripheral and central spatial summation and mixture suppression in taste were investigated by the “split-tongue” technique. In this method, stimuli are applied to one or both sides of the tongue in different combinations. Interactions between tongue sides must be central, whereas comparison with unilateral results provides information about peripheral vs central contributions [1].
Physiology & Behavior, Apr 1, 1995
The transduction of Na ÷ salts has been shown in many species to be mediated in part by an epithe... more The transduction of Na ÷ salts has been shown in many species to be mediated in part by an epithelial ion channel on the apical surface of the taste receptor cell membrane, which is blockable by the diuretic amiloride. In addition to this apical ion channel, Na ÷ is also transduced via a paracellular pathway, which is not sensitive to amiloride. There are significant species differences in the contribution of the amiloride-sensitive pathway to Na ÷ transduction. Previous human psychophysical studies have reported conflicting results on the effects of amiloride in suppressing the intensity of NaC1. In general, these studies used amiloride doses that were much higher than those showing clear suppressive effects in electropbysiological studies in other species. In the present experiment, we used direct magnitude scaling of the intensities of five NaCI concentrations flowed over the anterior portion of the tongue to determine the effects of amiloride treatment at lower doses. NaC1 was presented after adaptation of the tongue to water or mixed with and presented after adaptation to 10, 50, or 100 #M amiloride-HCI. Subjects estimated the intensity of NaCI and of these concentrations of amiloride in each treatment condition using magnitude estimation with a 0.1 M NaCI modulus presented following a water rinse prior to each session. Results showed that amiloride had a significant suppressive effect on the perceived intensity of NaCI, with a similar effect seen at all three amiloride doses. The psychophysical function after amiloride showed a parallel shift to the right. The average suppression over all NaCI concentrations was 21%. Calculations of the perceived intensity of previously published matching concentrations after 500/zM amiloride from the water-adapted NaCI function showed that the degree of suppression was equivalent between the previous report and the present one. These results suggest that the contribution of the amiloride-sensitive component to the transduction of Na + salts is smaller in humans than in many other species.
Chemical Senses, 1995
Sodium-salt transduction in many species may be mediated by both apical and submucosal ion channe... more Sodium-salt transduction in many species may be mediated by both apical and submucosal ion channels on the taste receptor cell membrane. The apical ion channel is blockable by the diuretic amiloride, whereas the submucosal pathway is not. Sodium salts with small anions, such as NaCl, can stimulate submucosal as well as apical ion channels; sodium salts with large anions, such as Na-gluconate, activate primarily the apical channels. In humans, reports on the effects of amiloride on the taste of NaCl are conflicting and no data exist on the effects of amiloride on organic sodium salts. In the present experiment, subjects gave magnitude estimates of the total intensity and of each of the basic taste qualities for NaCl, Na-gluconate and KCl. Five concentrations of each of these stimuli were presented to the anterior tongue following distilled water adaptation and after amiloride treatment. There was a significant decrease in the total taste intensity of NaCl and Na-gluconate after amiloride, but no effect on KCl. The saltiness of all three salts was unaffected, but amiloride decreased the perceived sourness of the sodium salts. KCl sourness was unaffected by amiloride. There was a proportionately larger effect of amiloride on Na-gluconate than on NaCl, which is consistent with a larger role for the apical ion channel in Na-gluconate transduction. However, an appreciable amiloride-insensitive component is present for both NaCl and Na-gluconate, suggesting that an amiloride-insensitive pathway also plays a role in the transduction of both sodium salts. These data support the hypothesis that an amiloride-sensitive transduction component exists in humans, but suggest that it is considerably smaller than in many other species.
Physiology & Behavior, Nov 1, 1996
Chemical Senses, 1997
Although there is compelling evidence that amiloride reduces the intensity of Na + and Li + salts... more Although there is compelling evidence that amiloride reduces the intensity of Na + and Li + salts in humans, its effects on saltiness are conflicting. Many salts elicit not only a salty taste but also one or more side tastes (sweetness, sourness or bitterness). Some studies have shown a suppression of saltiness by amiloride; others show no effect on saltiness but a significant reduction in sourness. In the experiments demonstrating a reduction of saltiness, subjects estimated only saltiness; in those showing an amiloride effect on sourness and not saltiness, subjects estimated all qualities on each trial. The present study examines the role of the psychophysical method in these conflicting results. We have investigated the effects of amiloride on taste quality by modifying only the instructions to the subjects, keeping all other variables constant. One group of subjects (intensity-only) gave magnitude estimates of the overall intensity of a LJCI concentration series. A second group (salty-only) was instructed to estimate the saltiness of the stimuli, and a third group (sour-only) estimated their sourness. Finally, a fourth group (profile) rated all of the taste qualities on each stimulus presentation, using a modified taste profile method. The ratings of all groups were made comparable by the use of 0.1 mM quinine-HCI as a modulus. When subjects used only one response category, amiloride reduced their estimates (of intensity, saltiness or sourness), but if subjects attended to all four qualities, amiloride specifically reduced the sourness of LiCI and had no significant effect on its saltiness. Comparison of the saltiness estimates of the salty-only group to the sum of the salty and sour estimates of the profile group demonstrated that subjects combined these sensations when presented with only one response alternative. To reveal the effect of amiloride on a specific quality of a salt, the psychophysical method must allow subjects to attend to all qualities on each trial. These data and previous results suggest that apical Na + channels on the taste receptor cell membrane mediate the sourness but not the saltiness of Na + and Li + salts. Chem. Senses 22: 267-275, 1997.
Chemical Senses, 1997
Although there is compelling evidence that amiloride reduces the intensity of Na + and Li + salts... more Although there is compelling evidence that amiloride reduces the intensity of Na + and Li + salts in humans, its effects on saltiness are conflicting. Many salts elicit not only a salty taste but also one or more side tastes (sweetness, sourness or bitterness). Some studies have shown a suppression of saltiness by amiloride; others show no effect on saltiness but a significant reduction in sourness. In the experiments demonstrating a reduction of saltiness, subjects estimated only saltiness; in those showing an amiloride effect on sourness and not saltiness, subjects estimated all qualities on each trial. The present study examines the role of the psychophysical method in these conflicting results. We have investigated the effects of amiloride on taste quality by modifying only the instructions to the subjects, keeping all other variables constant. One group of subjects (intensity-only) gave magnitude estimates of the overall intensity of a LJCI concentration series. A second group (salty-only) was instructed to estimate the saltiness of the stimuli, and a third group (sour-only) estimated their sourness. Finally, a fourth group (profile) rated all of the taste qualities on each stimulus presentation, using a modified taste profile method. The ratings of all groups were made comparable by the use of 0.1 mM quinine-HCI as a modulus. When subjects used only one response category, amiloride reduced their estimates (of intensity, saltiness or sourness), but if subjects attended to all four qualities, amiloride specifically reduced the sourness of LiCI and had no significant effect on its saltiness. Comparison of the saltiness estimates of the salty-only group to the sum of the salty and sour estimates of the profile group demonstrated that subjects combined these sensations when presented with only one response alternative. To reveal the effect of amiloride on a specific quality of a salt, the psychophysical method must allow subjects to attend to all qualities on each trial. These data and previous results suggest that apical Na + channels on the taste receptor cell membrane mediate the sourness but not the saltiness of Na + and Li + salts. Chem. Senses 22: 267-275, 1997.
Olfaction and Taste XI, 1994
Physiology & Behavior, 1995
The transduction of Na ÷ salts has been shown in many species to be mediated in part by an epithe... more The transduction of Na ÷ salts has been shown in many species to be mediated in part by an epithelial ion channel on the apical surface of the taste receptor cell membrane, which is blockable by the diuretic amiloride. In addition to this apical ion channel, Na ÷ is also transduced via a paracellular pathway, which is not sensitive to amiloride. There are significant species differences in the contribution of the amiloride-sensitive pathway to Na ÷ transduction. Previous human psychophysical studies have reported conflicting results on the effects of amiloride in suppressing the intensity of NaC1. In general, these studies used amiloride doses that were much higher than those showing clear suppressive effects in electropbysiological studies in other species. In the present experiment, we used direct magnitude scaling of the intensities of five NaCI concentrations flowed over the anterior portion of the tongue to determine the effects of amiloride treatment at lower doses. NaC1 was presented after adaptation of the tongue to water or mixed with and presented after adaptation to 10, 50, or 100 #M amiloride-HCI. Subjects estimated the intensity of NaCI and of these concentrations of amiloride in each treatment condition using magnitude estimation with a 0.1 M NaCI modulus presented following a water rinse prior to each session. Results showed that amiloride had a significant suppressive effect on the perceived intensity of NaCI, with a similar effect seen at all three amiloride doses. The psychophysical function after amiloride showed a parallel shift to the right. The average suppression over all NaCI concentrations was 21%. Calculations of the perceived intensity of previously published matching concentrations after 500/zM amiloride from the water-adapted NaCI function showed that the degree of suppression was equivalent between the previous report and the present one. These results suggest that the contribution of the amiloride-sensitive component to the transduction of Na + salts is smaller in humans than in many other species.
Chemical Senses, 1995
Sodium-salt transduction in many species may be mediated by both apical and submucosal ion channe... more Sodium-salt transduction in many species may be mediated by both apical and submucosal ion channels on the taste receptor cell membrane. The apical ion channel is blockable by the diuretic amiloride, whereas the submucosal pathway is not. Sodium salts with small anions, such as NaCl, can stimulate submucosal as well as apical ion channels; sodium salts with large anions, such as Na-gluconate, activate primarily the apical channels. In humans, reports on the effects of amiloride on the taste of NaCl are conflicting and no data exist on the effects of amiloride on organic sodium salts. In the present experiment, subjects gave magnitude estimates of the total intensity and of each of the basic taste qualities for NaCl, Na-gluconate and KCl. Five concentrations of each of these stimuli were presented to the anterior tongue following distilled water adaptation and after amiloride treatment. There was a significant decrease in the total taste intensity of NaCl and Na-gluconate after amiloride, but no effect on KCl. The saltiness of all three salts was unaffected, but amiloride decreased the perceived sourness of the sodium salts. KCl sourness was unaffected by amiloride. There was a proportionately larger effect of amiloride on Na-gluconate than on NaCl, which is consistent with a larger role for the apical ion channel in Na-gluconate transduction. However, an appreciable amiloride-insensitive component is present for both NaCl and Na-gluconate, suggesting that an amiloride-insensitive pathway also plays a role in the transduction of both sodium salts. These data support the hypothesis that an amiloride-sensitive transduction component exists in humans, but suggest that it is considerably smaller than in many other species.
Physiology & Behavior, 1997
Chemical Senses, 1997
Although there is compelling evidence that amiloride reduces the intensity of Na + and Li + salts... more Although there is compelling evidence that amiloride reduces the intensity of Na + and Li + salts in humans, its effects on saltiness are conflicting. Many salts elicit not only a salty taste but also one or more side tastes (sweetness, sourness or bitterness). Some studies have shown a suppression of saltiness by amiloride; others show no effect on saltiness but a significant reduction in sourness. In the experiments demonstrating a reduction of saltiness, subjects estimated only saltiness; in those showing an amiloride effect on sourness and not saltiness, subjects estimated all qualities on each trial. The present study examines the role of the psychophysical method in these conflicting results.
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Papers by Corinne Ossebaard