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Biomedical subjects

T Shingai

Publications and source records attributed to T Shingai.

14 recordsLinked to original sources
PubMed1989

Hypotonic diuresis following oropharyngeal stimulation with water in humans.

The role of oropharyngeal mechanisms in body water regulation was studied in 12 human males by measuring urine output and osmolality before and after drinking a very small volume of distilled water (0.15 ml/kg b.w.t.). Hypotonic diuresis was resulted only in the subjects (n = 6) who drank only sufficient water to keep their oropharynx moist continually over a 20 min period but not in those who (n = 6) drank the same volume of water within several seconds. Sham verbal instructions on drinking induced no changes in subjects examined. These results suggest that oropharyngeal afferents alone, and neither gastric afferents nor psychosomatic effects, may account for hypotonic diuresis following water intake in man.

Adult↗
PubMed1989

Swallowing reflex elicited by water and taste solutions in humans.

We investigated whether water and taste solutions are adequate stimuli for elicitation of the swallowing reflex from the pharyngolaryngeal region in humans. Subjects were five healthy males. Small amounts of water and taste solutions were applied to the posterior tongue of the subject as he reclined on a dental chair. The latency between the onset of application of the stimuli and the occurrence of swallowing was measured. Water was a most effective stimulus for elicitation of the swallowing reflex. The stimulatory effect was altered by anions, particularly Cl-, added to the water. Gustatory factors affected the latency of swallowing. The results suggest that humans have water-sensitive receptors in the pharyngolaryngeal region and that these receptors are responsible for initiation of the swallowing reflex by water.

Adult↗
PubMed1988

Diuresis mediated by the superior laryngeal nerve in rats.

Diuresis mediated by the superior laryngeal nerve (SLN) was investigated using pentobarbital-anesthetized rats. A marked increase in urine flow was induced by application of water to the larynx. The diuretic effect of water was conspicuous during the first 30 min after the application and lasted for more than 1 hr. In contrast, a 160 mM solution of NaCl produced only slight diuresis. After bilateral sectioning of the SLNs, water-induced diuresis was considerably reduced. The results suggest that water fibers contained in the SLN may make a major contribution to the diuresis.

Animals↗
PubMed1987

Changes in water intake following pharyngolaryngeal deafferentation in the rat.

The role of afferent information arising from the pharyngolaryngeal region in the regulation of water intake was evaluated in rats. The animals received picric application to the mucosa of either the pharyngolaryngeal or the hard palate region. Water intake of the pharyngolaryngeal treated animals was reduced significantly, while no reduction in water intake was shown in the control and hard palate treated animals.

Animals↗
PubMed1987

Sensation of thirst in normal and laryngectomized man.

The purpose of this study was to evaluate the role of the larynx in sensation of thirst and to identify precise areas responsible for the sensation in normal and laryngectomized groups. The present analysis showed that the laryngectomized group was less aware of the sensation and less able to localize it than the normal group. Both groups localized the sensation from the base of the tongue to the larynx as well as in the pharynx.

Adult↗
PubMed1987

Differences in drinking behavior between normal and laryngectomized man.

The properties of drinking in normal and laryngectomized groups were examined. Drinking associated with meals was more frequent in the 76 young and 37 older normal subjects than the 25 laryngectomized persons. The laryngectomized group preferred tea and coffee to water to alleviate thirst sensation, while such a preference was hardly seen in either normal group. Results suggest that the larynx may contribute not only to thirst sensation but may be associated with preference in drinking.

Adult↗
PubMed1985

Response characteristics of three taste nerves in mice.

Gustatory responses from 3 nerves, the chorda tympani, glossopharyngeal and superior laryngeal nerves were investigated in the mouse. Stimuli were NH4Cl, NaCl, KCl, HCl, quinine-HCl, sucrose, urea, glucose and distilled water. The 3 nerves responded differently to these stimuli. The chorda tympani responded strongly to HCl and sucrose, but weakly to quinine-HCl, while the glossopharyngeal responded well to quinine-HCl rather than to either HCl or sucrose. The order of effective stimulation was NH4Cl greater than NaCl greater than KCl for the chorda tympani, whereas NH4Cl greater than KCl greater than NaCl for the glossopharyngeal nerve. The responses of the superior laryngeal nerve were remarkably different from those of the others. Water was the most effective stimulus for the nerve and the response to water was depressed by either electrolytes or non-electrolytes added in water. These results suggest dissimilar contributions of the 3 nerves to the physiological functions.

Animals↗
PubMed1979

Physicochemical study of receptive mechanism of laryngeal water fibers in the rabbit.

The effects of various cations on the water unit activity were studied by recording unitary discharges in the superior laryngeal nerve fibers of the rabbit. Chloride salts of Li+, Na+, K+, Cs+ depressed the water response, while sulfate salts of Li+, Na+, NH4+, K+ facilitated it. Cations were less effective in stimulating action than anions. The depression of the water response in the laryngeal nerve has been thought to be caused by permeation of the stimulating anions through the receptor membrane and/or by destruction of the water structure on the membrane surface induced by adsorbed anions (SHINGAI, 1977 a). In order to differentiate these two possible actions of anions, the effects of benzenesulfonate and trichloroacetate were examined, because these anions were expected to be impermeant through the receptor membrane and to have a water structure-breaking effect. These anions showed no effect on the water response in concentrations below 320 mM. Measurements of the viscosity and the density of the electrolyte solutions showed that benzenesulfonate had a strong water structure-breaking effect. These results suggested that impermeant anions having water structure-breaking actions do not influence the excitability of the water receptor and that the depression of the water response by anions in the stimulating solution is caused by a hyperpolarization generated by permeation of the anions through the receptor membrane.

Animals↗
PubMed1977

Ionic mechanism of water receptors in the laryngeal mucosa of the rabbit.

The effects of various ions on water response was studied by recording unitary discharges in single superior laryngeal nerve fibers of the rabbit. The water response was strongly influenced by anions. The inorganic anions used were divided into two groups. One group consisted of anions which depress the water response (depressing anions), the depressing action sequence being SCN- greater than Br- greater than than Cl- greater than I- greater than NO-3. Another one consisted of anions which facilitate the water response (facilitating anions), the facilitating action sequence being citrate greater than SO34- greater than IO-3 greater than F- greater than BrO-3 greater than acetate. Physicochemically, facilitating anions belong to "the water structure-making ions" group; on the other hand, depressing anions belong to "the water structure-breaking ions" group. SO34- weakened the depressing effect of Cl- when the concentration of Cl- was below 60 mM, and enhanced it when the concentration was above 60 mM. Na+ and Li+ had no appreciable effect on the water unit activity, but K+ had a weakly stimulating effect. It is concluded that an outflux of anions through the membrane stimulates the water receptor while an influx of anions depresses it, and SO34- facilitates Cl- permeability. The mechanism of the facilitating effect of SO24- on Cl- permeation is discussed in terms of the interaction between the water structure surrounding the ions and the receptor membrane.

Animals↗
PubMed1976

Reflex swallowing elicited by water and chemical substances applied in the oral cavity, pharynx, and larynx of the rabbit.

Water and various chemical solutions were applied to the oral cavity, pharynx, and larynx of anesthetized rabbits to study their effects on the swallowing reflex. Laryngeal stimulation: Water was an effective stimulus in eliciting reflex swallowing; NaCL depressed this reflex. The effect of salt solutions on swallowing was dependent on anion species. Weakly hydrated anions had a depressing effect while greatly hydrated anions had a facilitating effect. The order of the depressing effect of the anions was Br-greater than SCN- greater than CL- congruent to NO3 -, and the order of the facilitating effect of anions was citrate greater than SO42 - greater than HCO3-. Oral and pharyngeal stimulation: Water elicited swallowing; however, this effect was less marked than that in the larynx. NaCL in concentrations lower than 200 mM had a depressing effect while at higher concentration it had a facilitating effect. Sucrose, acetic acid, and alcohol evoked successive swallowing in the first two or three trials. It was found that water applied to the laryngeal region had the marked effect of eliciting reflex swallowing and that most gustatory substances infused into the oral and pharyngeal regions had a facilitating effect on the initation of swallowing.

Acetates↗