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.

Glossopharyngeal nerve transection does not compromise the specificity of taste-guided sodium appetite in rats

1995 ◽  
Vol 269 (1) ◽  
pp. R215-R221 ◽  
Author(s):  
S. Markison ◽  
S. J. St John ◽  
A. C. Spector
Keyword(s):  
Salivary Glands ◽  
Drinking Behavior ◽  
Lick Rate ◽  
Glossopharyngeal Nerve ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Sodium Appetite ◽  
Response Profiles ◽  
Altered Response

The chorda tympani nerve (CT) has been shown to be critical in the sodium-specific drinking behavior of sodium-depleted rats, but the role of other gustatory nerves and the contribution of the major salivary glands remain to be elucidated. In this study, rats received either bilateral section of the CT (CTX) or the glossopharyngeal nerve (GLX), extirpation of the sublingual and submaxillary salivary glands (DSAL), or sham surgery. After recovery, rats were sodium depleted with furosemide and tested for their licking responses to 0.05 and 0.3 M NaCl, KCl, CaCl2, and NH4Cl, as well as distilled water in an automated gustometer. Rats that received GLX maintained a specific sodium appetite comparable to controls despite denervation of approximately 64% of the taste buds. In contrast, compared with control rats, CTX and DSAL rats had altered response profiles, showing much smaller differences in licking to NaCl relative to the other stimuli. This was accompanied by a substantially lower lick rate in DSAL rats, raising the possibility that general licking impairments contributed to the decreased NaCl responsiveness in these rats. These findings imply that the CT, but not the glossopharyngeal nerve, is necessary for the maintenance of normal sodium-specific, taste-guided behavior under sodium deplete conditions.

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.

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.

Chorda Tympani in Chronic Inflammatory Middle Ear Disease

2008 ◽  
Vol 139 (2_suppl) ◽  
pp. P52-P53
Author(s):  
Arun Goyal ◽  
P P Singh ◽  
Gautam Dash
Keyword(s):  
Middle Ear ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Retraction Pocket ◽  
Taste Strips ◽  
Disease Site ◽  
Middle Ear Disease ◽  
The Mean ◽  
The Difference ◽  
A Prospective Study

Objective To study the effect of chronic inflammatory middle ear disease on gustatory function of chorda tympani nerve. Methods A prospective study was performed in 2007 on 85 patients of unilateral chronic inflammatory middle ear disease of both cholesteatomatous and noncholesteatomatous type. Gustatory assessment on both sides of the tongue was performed using dry taste strips. Taste strips were made of filter paper soaked in four different taste solutions of four different concentrations each and dried. The taste score is the number of correctly identified taste strips. Results were analyzed using Analysis of Variance (ANOVA) and t-test. Results Comparison of mean taste scores on the side of diseased ear with normal ear was done. On the diseased side, the mean taste score was 9.16 and on the normal side, the mean taste score was 13.24. The difference between the two was found to be statistically significant (p<0.0001). The results were also analyzed for various other parameters like type, duration, and location of disease. Site of cholesteatoma was found to have a significant effect on the taste score of the diseased side. Patients having postero-superior retraction pocket cholesteatoma had significantly lower taste scores as compared to those having cholesteatoma at other sites (p=0.008). Conclusions A patient of chronic inflammatory middle ear disease already has dysfunctional chorda tympani and is unlikely to notice a change in the taste sensation in the event of cutting of the nerve during the course of an ear surgery.

Schwannoma of the chorda tympani nerve

2000 ◽  
Vol 114 (1) ◽  
pp. 81-82 ◽  
Author(s):  
S. T. Browning ◽  
J. J. Phillipps ◽  
N. Williams
Keyword(s):  
Benign Tumour ◽  
The Other ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Auditory Function ◽  
Conductive Deafness ◽  
First Case ◽  
Rare Benign Tumour

We report a case of schwannoma of the chorda tympani. This is a very rare benign tumour and only five other cases have been found in the literature. This is the first case to mimic a cholesteatoma presenting as a pearly tumour in the postero-superior segment of the drum with aural discharge and conductive deafness. Diagnosis is usually by biopsy and treatment is surgical with preservation of facial and auditory function. A summary of the other presentations of this tumour together with a review of the histopathology of the disease is presented.

Sodium specificity of salt appetite in Fischer-344 and Wistar rats is impaired by chorda tympani nerve transection

1995 ◽  
Vol 269 (2) ◽  
pp. R350-R356 ◽  
Author(s):  
P. A. Breslin ◽  
A. C. Spector ◽  
H. J. Grill
Keyword(s):  
Wistar Rats ◽  
Sodium Balance ◽  
Salt Appetite ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Sodium Depletion ◽  
Rat Strains ◽  
Fischer 344 ◽  
Chloride Salts ◽  
F344 Rats

Unlike other rat strains, the sodium-replete Fischer-344 (F344) strain shows no innate preference for NaCl and displays more aversive and fewer ingestive oral motor responses to orally infused NaCl when tested in sodium balance. Despite these differences, F344 rats show an increase in preference for NaCl in response to sodium depletion. The present study was designed to determine whether the salt appetite of sodium-depleted F344 rats is cation specific and whether such selectivity is mediated in part by an intact chorda tympani nerve. Sodium-depleted (10 mg furosemide) F344 (n = 13) and Wistar (n = 16) rats were permitted repeated access to nine stimuli (water, and 0.05 and 0.3 M NaCl, KCl, NH4Cl, and CaCl2), presented randomly in 10-s trials. One-half of the rats had their chorda tympani nerve sectioned (CTX). Under conditions of sodium depletion, both strains discriminated NaCl from other chloride salts. CTX significantly impaired the selectivity of the licking behavior in both strains, suggesting that sodium-specific licking is partially mediated by anterior tongue taste receptors. These findings suggest that both sodium-depleted F344 and Wistar rats are comparable in their abilities to recognize NaCl, to distinguish it from other salts, and to respond selectively to it, despite the fact that sodium-replete F344 and Wistar rats differ greatly in their NaCl preference.

S213 – Gustatory Alterations in Patients with Chronic Otitis Media

2008 ◽  
Vol 139 (2_suppl) ◽  
pp. P147-P147
Author(s):  
Felippe Felix ◽  
Reis Jamerson ◽  
Gustavo A. Porto Sereno Cabral ◽  
Carleti Guilherme ◽  
Fernando Souza De Barros ◽  
...  
Keyword(s):  
Otitis Media ◽  
Poisson Regression ◽  
Chronic Otitis Media ◽  
The Other ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Affected Side ◽  
Prior Surgery ◽  
The Mean ◽  
Disease Free

Objectives 1) To identify gustatory alterations due to chorda tympani nerve involvement in patients with chronic otitis media (COM) without prior surgery, and 2) To see if the presence of cholesteatoma worsened gustatory sensitivity in these patients. Methods Study Design: prospective study. The test was performed in patients with unilateral cholesteatomatous or suppurated COM not previously submitted to otological surgery. The test was based on “taste strips” with different concentrations of salt, sweet, bitter, and sour, using the otological disease-free side as the control. The score could be between 0 (worst) and 16 (best). All the other data were collected by interview and physical exam and analysed by Poisson Regression. Results A total of 45 patients with COM were evaluated, including 25 with cholesteatoma and 20 with non-cholesteatomatous COM, with a mean age of 38 years. 8 cases of unilateral ageusia were found on the affected side. The mean score was 6.65 for the affected side and 9.91 for the half of the tongue on the side of the healthy ear (p<0,05). No patients had complained of gustatory alterations before the examination. There was an association between presence of cholesteatoma and worse gustatory sensitivity (p<0.05). Conclusions Patients with cholesteatomatous or suppurated COM can present gustatory alterations, even in the absence of complaints. The presence of cholesteatoma worsened gustatory sensitivity.

Taste-responsive neurons of the glossopharyngeal nerve of the rat

1991 ◽  
Vol 65 (6) ◽  
pp. 1452-1463 ◽  
Author(s):  
M. E. Frank
Keyword(s):  
Receptive Fields ◽  
Nerve Impulse ◽  
Response Spectra ◽  
Glossopharyngeal Nerve ◽  
Taste Bud ◽  
Similar Response ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Vallate Papillae ◽  
Chloride Salts

1. Taste sensibilities of neurons in mammalian glossopharyngeal nerves have been inadequately studied, although they innervate the majority of taste buds and may provide unique taste information. 2. Extracellular responses of glossopharyngeal neural units to taste stimuli infused into foliate or vallate papillae were recorded in anesthetized rats. A 0.3-ml/min infusion of stimuli into papillae resulted in short-latency, 5-s nerve-impulse rates that approached 10 times the response rates observed using less invasive means of stimulation. 3. Sucrose, Na saccharin, NaCl, NH4Cl, KCl, HCl, citric acid, acetic acid, MgSO4, and quinine.HCl were effective stimuli for glossopharyngeal neurons at concentrations that have behavioral significance. 4. Response spectra for individual neural units with either foliate or vallate receptive fields fell into three clusters. Forty-six percent were A units that responded most strongly to acids and chloride salts, NH4Cl being the most effective; neither quinine nor sucrose was effective. Twenty-three percent were S units that responded to sugars and saccharin; quinine, salts, and acids were not effective. Thirty-one percent were Q units that responded to quinine; neither NaCl, HCl, nor sucrose was effective stimulus for these fragile units. 5. Glossopharyngeal A neural units were more sensitive to 1 mM HCl than were electrolyte-sensitive H units of the chorda tympani, although both respond generally to salts and acids. Units relatively specific for sodium salts (N units), which are common in the chorda tympani nerve, were not found in the glossopharyngeal nerve, which explains losses in sodium-specific behavior after cutting only the chorda tympani nerve. 6. Q units were the only glossopharyngeal neural units that responded significantly to quinine, and units with similar response spectra do not occur in the chorda tympani nerve. Q units probably mediate aversive reflexes to quinine that are eliminated by cutting only the glossopharyngeal nerve. Glossopharyngeal S neural units were more sensitive to sucrose and are more common than their counterparts in the chorda tympani, although it is not known how they might compare with sugar-sensitive units in the greater superficial petrosal nerve. 7. These data strongly suggest that posterior taste bud fields innervated by the glossopharyngeal nerve are specialized for functions different from those of anterior taste bud fields innervated by the facial nerve.

Spatial map of salts and saccharides on dog tongue

1988 ◽  
Vol 255 (1) ◽  
pp. R117-R122
Author(s):  
J. L. Garvin ◽  
R. Robb ◽  
S. A. Simon
Keyword(s):  
Spatial Heterogeneity ◽  
Open Circuit Potential ◽  
Short Circuit ◽  
Short Circuit Current ◽  
Open Circuit ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Lingual Epithelium ◽  
Ussing Chambers ◽  
Chloride Salts

Front and rear regions of dog tongue were tested for spatial heterogeneity with respect to monovalent chloride salts (NaCl, KCl, and NH4Cl) and sweet tastants (sucrose, D-glucose, and L-glucose) by placing them in Ussing chambers where the open-circuit potential, Voc, and short-circuit current, Isc, were measured. The responses of Voc and Isc to 0.5 M NaCl were greater in the front of the tongue than in the rear, whereas the responses of Voc and Isc to 0.5 M sucrose were greater in the rear of the tongue than in the front. These results are similar to those of published neurophysiological measurements from the chorda tympani nerve and thalamus. These data suggest that the spatial heterogeneities seen in higher taste centers are present in the isolated lingual epithelium where primary taste transduction events occur.

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