Sweet Taste Responses of Mouse Chorda Tympani Neurons: Existence of Gurmarin-Sensitive and -Insensitive Receptor Components

1999 ◽  
Vol 81 (6) ◽  
pp. 3087-3091 ◽  
Author(s):  
Yuzo Ninomiya ◽  
Toshiaki Imoto ◽  
Tadataka Sugimura
Keyword(s):  
Sweet Taste ◽  
The Other ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Inhibitory Effects ◽  
Single Fibers ◽  
Taste Cells ◽  
C57bl Mice ◽  
Mouse Taste

Sweet taste responses of mouse chorda tympani neurons: existence of gurmarin-sensitive and -insensitive receptor components. Inhibitory effects of gurmarin (gur) on responses to sucrose and other sweeteners of single fibers of the chorda tympani nerve in C57BL mice were examined. Of 30 single fibers that strongly responded to 0.5 M sucrose but were not or to lesser extent responsive to 0.1 M NaCl, 0.01 M HCl, and 0.02 M quinine HCl (sucrose-best fibers), 16 fibers showed large suppression of responses to sucrose and other sweeteners by lingual treatment with 4.8 μM (∼20 μg/ml) gur (suppressed to 4–52% of control: gur-sensitive fibers), whereas the remaining 14 fibers showed no such gur inhibition (77–106% of control: gur-insensitive fibers). In gur-sensitive fibers, responses to sucrose inhibited by gur recovered to ∼70% of control responses after rinsing the tongue with 15 mM β-cyclodextrin and were almost abolished by further treatment with 2% pronase. In gur-insensitive fibers, sucrose responses were not inhibited by gur, but were largely suppressed by pronase. These results suggest existence of two different receptor components for sweeteners with different susceptibilities to gur in mouse taste cells, one gur sensitive and the other gur insensitive. Taste cells possessing each component may be specifically innervated by a particular type of chorda tympani neurons.

Salt taste responses of mouse chorda tympani neurons: evidence for existence of two different amiloride-sensitive receptor components for NaCl with different temperature dependencies

1996 ◽  
Vol 76 (5) ◽  
pp. 3550-3554 ◽  
Author(s):  
Y. Ninomiya
Keyword(s):  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Inhibitory Effects ◽  
Strong Suppression ◽  
Salt Taste ◽  
Single Fibers ◽  
Different Temperatures ◽  
Higher Temperature ◽  
Lower Temperature ◽  
Mouse Taste

1. Inhibitory effects of amiloride on salt responses of single fibers of the chorda tympani nerve of the C57BL/6 strain of mice were examined at two different temperatures (approximately 12 and 24 degrees C). 2. Of 36 single fibers that responded to NaCl, 20 fibers showed strong suppression of responses to NaCl actuated by lingual treatment with amiloride (amiloride-sensitive fibers), whereas the remaining 16 fibers showed no such amiloride inhibition (amiloride-insensitive fibers). 3. Twenty amiloride-sensitive fibers were further classified into two subgroups according to the temperature dependency of their NaCl responses. In 15 of 20 fibers, amiloride-inhibitable NaCl responses were larger at 24 degrees C than at 12 degrees C, whereas the reverse was true for the remaining 5 fibers. All amiloride-insensitive fibers showed smaller responses to NaCl at 12 degrees C. 4. These results suggest that there exist two different amiloride-sensitive receptor components for NaCl with different temperature dependencies in mouse taste cells: one is more sensitive to NaCl at the higher temperature, and the other is more sensitive at the lower temperature.

Gurmarin inhibition of sweet taste responses in mice

1995 ◽  
Vol 268 (4) ◽  
pp. R1019-R1025 ◽  
Author(s):  
Y. Ninomiya ◽  
T. Imoto
Keyword(s):  
Sweet Taste ◽  
Suppressive Effect ◽  
Taste Receptors ◽  
Gymnema Sylvestre ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Inhibitory Effects ◽  
Sweet Taste Receptors ◽  
Before And After ◽  
C57bl Mice

The inhibitory effects of gurmarin (a peptide isolated from the leaves of Gymnema sylvestre) on sweet taste responses were studied by examining the chorda tympani nerve responses to various taste substances before and after lingual treatment with gurmarin in C57BL and BALB mice. Treatment with gurmarin at 3 micrograms/ml or more selectively suppressed responses to sucrose without affecting responses to NaCl, HCl, and quinine in C57BL mice, whereas gurmarin at 100 micrograms/ml did not significantly suppress sucrose responses in BALB mice. Responses to various sweet substances in C57BL mice decreased to approximately 45-75% of control after gurmarin, and the suppressive effect of gurmarin was reversible. The profile of the residual responses of C57BL mice to various sweeteners after gurmarin was almost identical to that of BALB mice, which was hardly affected by gurmarin. These results strongly suggest that there are at least two types of sweet taste receptors in mice, gurmarin-sensitive and -insensitive. Probably, C57BL and BALB mice share an identical gurmarin-insensitive receptor, and C57BL mice also have a gurmarin-sensitive receptor.

scholarly journals Expression of Amiloride-sensitive Epithelial Sodium Channels in Mouse Taste Cells after Chorda Tympani Nerve Crush

2005 ◽  
Vol 30 (6) ◽  
pp. 531-538 ◽  
Author(s):  
Noriatsu Shigemura ◽  
Abu Ahammad S. Islam ◽  
Chiharu Sadamitsu ◽  
Ryusuke Yoshida ◽  
Keiko Yasumatsu ◽  
...  
Keyword(s):  
Sodium Channels ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Epithelial Sodium Channels ◽  
Nerve Crush ◽  
Taste Cells ◽  
Mouse Taste

Chorda tympani section decreases the cation specificity of depletion-induced sodium appetite in rats

1993 ◽  
Vol 264 (2) ◽  
pp. R319-R323 ◽  
Author(s):  
P. A. Breslin ◽  
A. C. Spector ◽  
H. J. Grill
Keyword(s):  
Lick Rate ◽  
Single Stimulus ◽  
The Other ◽  
Chloride Salt ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Diuretic Treatment ◽  
Sodium Appetite ◽  
The Difference ◽  
Chloride Salts

Rats depleted of sodium by diuretic treatment were tested for their ability to respond selectively to NaCl after chorda tympani nerve (CTn) section (CTX). A variety of chloride salts (NaCl, KCl, NH4Cl, CaCl2) at two concentrations (0.05 and 0.3 M) were presented semirandomly to sodium-deplete rats in repeated single-stimulus trials (10 s). The responses of sodium-depleted surgical control rats (n = 8) were highly cation specific. These rats licked substantially more for both sodium stimuli than for any other chloride salt. On the other hand, the licking responses of CTX sodium-depleted rats (n = 8) were less cation selective. These rats licked NaCl and 0.05 M KCl at comparable rates. For both NaCl concentrations, CTX rats had significantly lower lick rates than controls. In addition, the difference between the lick rate for NaCl and that for the other salts was much greater for control rats than for CTX rats. Although CTn section did not entirely eliminate the high levels of responsivity to NaCl observed in the intact sodium-depleted rat, it did substantially compromise the selectivity of the behavior, which suggests that the input of the CTn is critical for taste-guided sodium specific behaviors.

scholarly journals Optogenetic Activation of Type III Taste Cells Modulates Taste Responses

2020 ◽  
Vol 45 (7) ◽  
pp. 533-539
Author(s):  
Aurelie Vandenbeuch ◽  
Courtney E Wilson ◽  
Sue C Kinnamon
Keyword(s):  
Light Response ◽  
Sensory Nerves ◽  
Taste Bud ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Type Iii ◽  
Nonspecific Effects ◽  
Taste Cells ◽  
Specific Stimulation ◽  
The Brain

Abstract Studies have suggested that communication between taste cells shapes the gustatory signal before transmission to the brain. To further explore the possibility of intragemmal signal modulation, we adopted an optogenetic approach to stimulate sour-sensitive (Type III) taste cells using mice expressing Cre recombinase under a specific Type III cell promoter, Pkd2l1 (polycystic kidney disease-2-like 1), crossed with mice expressing Cre-dependent channelrhodopsin (ChR2). The application of blue light onto the tongue allowed for the specific stimulation of Type III cells and circumvented the nonspecific effects of chemical stimulation. To understand whether taste modality information is preprocessed in the taste bud before transmission to the sensory nerves, we recorded chorda tympani nerve activity during light and/or chemical tastant application to the tongue. To assess intragemmal modulation, we compared nerve responses to various tastants with or without concurrent light-induced activation of the Type III cells. Our results show that light significantly decreased taste responses to sweet, bitter, salty, and acidic stimuli. On the contrary, the light response was not consistently affected by sweet or bitter stimuli, suggesting that activation of Type II cells does not affect nerve responses to stimuli that activate Type III cells.

scholarly journals Acetic acid modulates spike rate and spike latency to salt in peripheral gustatory neurons of rats

2012 ◽  
Vol 108 (9) ◽  
pp. 2405-2418 ◽  
Author(s):  
Joseph M. Breza ◽  
Robert J. Contreras
Keyword(s):  
Acetic Acid ◽  
Artificial Saliva ◽  
Type I ◽  
Dependent Manner ◽  
Chorda Tympani ◽  
Gustatory System ◽  
Chorda Tympani Nerve ◽  
Concentration Dependent Manner ◽  
Lingual Epithelium ◽  
Taste Cells

Sour and salt taste interactions are not well understood in the peripheral gustatory system. Therefore, we investigated the interaction of acetic acid and NaCl on taste processing by rat chorda tympani neurons. We recorded multi-unit responses from the severed chorda tympani nerve (CT) and single-cell responses from intact narrowly tuned and broadly tuned salt-sensitive neurons in the geniculate ganglion simultaneously with stimulus-evoked summated potentials to signal when the stimulus contacted the lingual epithelium. Artificial saliva served as the rinse and solvent for all stimuli [0.3 M NH4Cl, 0.5 M sucrose, 0.1 M NaCl, 0.01 M citric acid, 0.02 M quinine hydrochloride (QHCl), 0.1 M KCl, 0.003–0.1 M acetic acid, and 0.003–0.1 M acetic acid mixed with 0.1 M NaCl]. We used benzamil to assess NaCl responses mediated by the epithelial sodium channel (ENaC). The CT nerve responses to acetic acid/NaCl mixtures were less than those predicted by summing the component responses. Single-unit analyses revealed that acetic acid activated acid-generalist neurons exclusively in a concentration-dependent manner: increasing acid concentration increased response frequency and decreased response latency in a parallel fashion. Acetic acid suppressed NaCl responses in ENaC-dependent NaCl-specialist neurons, whereas acetic acid-NaCl mixtures were additive in acid-generalist neurons. These data suggest that acetic acid attenuates sodium responses in ENaC-expressing-taste cells in contact with NaCl-specialist neurons, whereas acetic acid-NaCl mixtures activate distinct receptor/cellular mechanisms on taste cells in contact with acid-generalist neurons. We speculate that NaCl-specialist neurons are in contact with type I cells, whereas acid-generalist neurons are in contact with type III cells in fungiform taste buds.

scholarly journals The relation between secretory and capillary pressure. I.—The salivary secretion

1912 ◽  
Vol 85 (579) ◽  
pp. 312-319 ◽  
Keyword(s):  
Arterial Pressure ◽  
Submaxillary Gland ◽  
Glass Tube ◽  
Salivary Secretion ◽  
External Jugular Vein ◽  
The Other ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Side Hole ◽  
The Right

Since Ludwig made the discovery that the secretory pressure of a gland may double that of the arterial pressure when the outflow of saliva is obstructed, no one, so far as we know, has investigated the circulatory conditions, in the gland under these circumstances. This has been the object of the present research. Our method is as follows:—We place a cannula in the duct of the submaxillary gland of the cat or dog and prepare the chorda tympani nerve for excitation. A second cannula is placed in the carotid artery of the opposite side of the neck. Each cannula is connected, either with a mercurial manometer or, as in our latest experiments, with two Leonard Hill pocket sphygmometer gauges. This gauge consists of a thick-walled glass tube with a fine capillary lumen closed at one end where the lumen expands into a small air chamber. Half an inch from the open end there is a side hole. On placing this end in a solution of potash a fluid meniscus rises to the side hole, which marks the zero of the instrument. (Potash is used to keep the tube free from grease.) One end of a piece of rubber is slipped over the open end of the gauge so as to cover the side hole, and the other end then connected with the cannula. The pressure of the saliva or blood forces the meniscus up the gauge, which is graduated in millimetres of mercury and acts as a spring manometer. We find these gauges very convenient to use as they can be placed side by side and the readings compared at a glance. Before making the connections with the gauges we expose the veins which course over the submaxillary gland and contribute to the formation of the external jugular vein. Having found the vein which issues from the gland we tie all the other veins, leaving this one free so that at the right moment we can clip the external jugular and open it so as to observe the outflow of blood from the gland. When all is thus prepared we excite the chorda tympani nerve. As soon as the secretory pressure rises above the arterial pressure we open the vein and observe the flow of blood. We find that under these conditions the blood continues to flow and issues from the vein in a fairly ample stream of a colour more arterial than venous. The gland itself feels tense to the touch. By squeezing the gland we find that we can further raise the pressure of the secretion, while at the same time we impede the outflow of blood. On allowing the secretory pressure to fall to atmospheric pressure we find that the outflow from the vein becomes much ampler; in one experiment it was approximately doubled, e. g. 40 drops in 15 seconds as compared with 27 drops in 20 seconds at the highest secretory pressure (240 mm. Hg.). In some experiments we observed the venous outflow from the time we began to excite the chorda tympani. Under these circumstances we find that the outflow from the gland at rest is very slow and the blood venous in colour. On stimulating the chorda, the outflow becomes very ample, the blood arterial in colour, and remains so during the rise of secretory pressure until this pressure rises higher than the arterial, when the outflow becomes lessened and the blood less arterial in colour.

scholarly journals Effects of voltage perturbation of the lingual receptive field on chorda tympani responses to Na+ and K+ salts in the rat: implications for gustatory transduction.

1994 ◽  
Vol 104 (5) ◽  
pp. 885-907 ◽  
Author(s):  
Q Ye ◽  
G L Heck ◽  
J A DeSimone
Keyword(s):  
Receptive Field ◽  
Voltage Clamp ◽  
Maximal Response ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Salt Taste ◽  
Negative Voltage ◽  
Voltage Clamp Condition ◽  
Taste Cells ◽  
Clamp Condition

Taste sensory responses from the chorda tympani nerve of the rat were recorded with the lingual receptive field under current or voltage clamp. Consistent with previous results (Ye, Q., G. L. Heck, and J. A. DeSimone. 1993. Journal of Neurophysiology. 70:167-178), responses to NaCl were highly sensitive to lingual voltage clamp condition. This can be attributed to changes in the electrochemical driving force for Na+ ions through apical membrane transducer channels in taste cells. In contrast, responses to KCl over the concentration range 50-500 mM were insensitive to the voltage clamp condition of the receptive field. These results indicate the absence of K+ conductances comparable to those for Na+ in the apical membranes of taste cells. This was supported by the strong anion dependence of K salt responses. At zero current clamp, the potassium gluconate (KGlu) threshold was > 250 mM, and onset kinetics were slow (12 s to reach half-maximal response). Faster onset kinetics and larger responses to KGlu occurred at negative voltage clamp (-50 mV). This indicates that when K+ ion is transported as a current, and thereby uncoupled from gluconate mobility, its rate of delivery to the K+ taste transducer increases. Analysis of conductances shows that the paracellular pathway in the lingual epithelium is 28 times more permeable to KCl than to KGlu. Responses to KGlu under negative voltage clamp were not affected by agents that are K+ channel blockers in other systems. The results indicate that K salt taste transduction is under paracellular diffusion control, which limits chemoreception efficiency. We conclude that rat K salt taste occurs by means of a subtight junctional transducer for K+ ions with access limited by anion mobility. The data suggest that this transducer is not cation selective which also accounts for the voltage and amiloride insensitive part of the response to NaCl.

Recovery of two independent sweet taste systems during regeneration of the mouse chorda tympani nerve after nerve crush

2007 ◽  
Vol 26 (6) ◽  
pp. 1521-1529 ◽  
Author(s):  
Keiko Yasumatsu ◽  
Yoko Kusuhara ◽  
Noriatsu Shigemura ◽  
Yuzo Ninomiya
Keyword(s):  
Sweet Taste ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Nerve Crush
Sign in / Sign up

Export Citation Format

Share Document