Chemospecific deficits in taste detection after selective gustatory deafferentation in rats

1990 ◽  
Vol 258 (3) ◽  
pp. R820-R826 ◽  
Author(s):  
A. C. Spector ◽  
G. J. Schwartz ◽  
H. J. Grill
Keyword(s):  
Detection Threshold ◽  
Conditioned Avoidance ◽  
Taste Bud ◽  
Taste Receptors ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Before And After ◽  
The Mean ◽  
Taste Detection ◽  
Response To Water

Electrophysiological data support the existence of sodium-specific taste receptors that appear to be limited to the anterior tongue. However, previous behavioral findings suggest that bilateral transection of the chorda tympani nerve (CTn) has minimal consequences on NaCl intake and preference. This study employed a conditioned avoidance procedure to measure detection thresholds to NaCl and sucrose both before and after bilateral transection of the CTn. Rats were trained to maintain spout contact in response to water presentations (70 microliters) and to avoid spout contact when a taste solution (70 microliters) was presented. In experiment 1, all rats (n = 3) showed statistically significant impairments in the detectability of NaCl after bilateral section of the CTn. The mean increase in the NaCl detection threshold was 1.41 log units. In contrast, sucrose threshold in these same rats was marginally affected by CTn section (mean increase = 0.22 log units). Experiment 2 (n = 4) replicated the findings of the first experiment. The mean increase in the NaCl detection threshold was 2.23 log units. Sucrose threshold in these rats was, again, only marginally affected by CTn section (mean increase = 0.83 log units). Histological examination of the anterior tongue from the rats in experiment 2 indicated that the CTn transections were complete. These findings reveal that the anterior oral receptive field (innervated by the CTn) containing only 15% of the total taste bud population is critical for the normal detection of NaCl.

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 Endoscopic Ossiculoplasty for the Management of Isolated Congenital Ossicular Chain Malformation: Surgical Results in 16 Ears

2020 ◽  
pp. 014556132093121
Author(s):  
Chunlin Zhang ◽  
Jiaoping Mi ◽  
Dan Long ◽  
Yuan Deng ◽  
Qiang Sun ◽  
...  
Keyword(s):  
Bone Conduction ◽  
Ossicular Chain ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Hearing Outcome ◽  
Before And After ◽  
Ossicular Replacement ◽  
The Mean ◽  
Replacement Prosthesis ◽  
Air Conduction

Objective: The aim of this study is to describe the clinical characteristics and intraoperative findings and further evaluate the efficacy of endoscopic ossiculoplasty for the management of isolated congenital ossicular chain malformation. Methods: A retrospective study was performed on 16 ears (15 patients) with the isolated congenital ossicular chain malformation who underwent endoscopic ossiculoplasty in our department from May 2017 to January 2019. Endoscopic exploratory tympanotomy was conducted to check the ossicular chain; at the same time, endoscopic ossiculoplasty was performed depending on intraoperative findings. Air-conduction thresholds, bone-conduction thresholds, and air-bone gaps (ABGs) were measured before and after surgery, and the hearing outcome was assessed at 6 months postoperatively. Results: The most common malformations of ossicular chain were the missing of the incus long process and stapes suprastructure. A serial assessment of the hearing status was conducted before and 6 months after surgery. It showed the mean postoperative pure-tone average (PTA) was significantly reduced, and the mean postoperative ABG was obviously closed, respectively ( P < .001). The mean PTA gain was 36.3 ± 8.6 dB, and the ABG closure was 35.1 ± 8.3 dB; ABG closure to 20 dB or less and ABG closure to 10 dB or less were achieved in 14 cases (87.5%) and 5 cases (31.3%), respectively. No differences were observed in postoperative hearing outcome between type Ⅲ cases and type Ⅳ cases; however, cases with partial ossicular replacement prosthesis implantation showed a larger hearing gain ( P = .049) and a higher proportion of postoperative ABG less than 10 dB ( P = .021). No facial palsy and significant sensorineural hearing loss occurred; all patients completed the surgery without the need of canalplasty, and the chorda tympani nerve was preserved in all patients. Conclusions: This research showed endoscopic surgery was effective in the diagnosis and management of isolated congenital ossicular chain malformation; the endoscopic ossiculoplasty provides an alternative method to manage congenital ossicular chain malformation, with comfortable hearing outcome and the advantage of excellent vision and less invasion.

scholarly journals Duloxetine for the management of sensory and taste alterations, following iatrogenic damage of the lingual and chorda tympani nerve

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Khan Junad ◽  
Sood Ruchika ◽  
Anwer Moin ◽  
Kalladka Mythili
Keyword(s):  
Nerve Injury ◽  
Detection Threshold ◽  
Complete Recovery ◽  
Pain Clinic ◽  
Chorda Tympani ◽  
Electrical Detection ◽  
Chorda Tympani Nerve ◽  
Taste Changes ◽  
Patient Reported ◽  
Taste Detection

AbstractObjectivesNerve injury may lead to pain and sensory changes such as dysesthesia and paresthesia. Quantitative sensory testing (QST) is a psychophysical testing method used to quantify nerve damage and monitor its recovery. Duloxetine is used in the management of neuropathic pain conditions, but its effect on taste recovery has not been previously reported.Case representationA 65-year-old female, presented to the orofacial pain clinic, with a chief complaint of a burning sensation on the tongue, taste changes and a feeling of tightness beneath the tongue for five months. She reported that the complaints began subsequent to a complicated dental extraction during which she experienced trauma to the tongue. Patient was advised to take duloxetine 60 mg in divided doses three times daily. The assessment and monitoring of the recovery pattern were performed using QST. Electrical taste detection (mediated by chorda tympani) and electrical detection/tingling thresholds were performed at periodic intervals for up to a year following the nerve injury in the chorda tympani and lingual nerve territory. The patient reported complete recovery in taste sensation with duloxetine and this correlated with the QST results. QST documented at the end of one year revealed the electrical taste detection threshold and electrical detection threshold return to near normal values.ConclusionsQST may be a useful diagnostic tool to assess and monitor lingual and chorda tympani nerve injuries. Duloxetine may aid in the recovery of the taste changes following lingual and chorda tympani nerve injury.

scholarly journals Development of Rat Chorda Tympani Sodium Responses: Evidence for Age-Dependent Changes in Global Amiloride-Sensitive Na+Channel Kinetics

2000 ◽  
Vol 84 (3) ◽  
pp. 1531-1544 ◽  
Author(s):  
Susan J. Hendricks ◽  
Robert E. Stewart ◽  
Gerard L. Heck ◽  
John A. DeSimone ◽  
David L. Hill
Keyword(s):  
Kinetic Model ◽  
Maximum Rate ◽  
Taste Receptor ◽  
Taste Bud ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Channel Density ◽  
Age Dependent ◽  
Response Increase ◽  
Apical Membranes

In rat, chorda tympani nerve taste responses to Na+ salts increase between roughly 10 and 45 days of age to reach stable, mature magnitudes. Previous evidence from in vitro preparations and from taste nerve responses using Na+ channel blockers suggests that the physiological basis for this developmental increase in gustatory Na+ sensitivity is the progressive addition of functional, Na+ transduction elements (i.e., amiloride-sensitive Na+ channels) to the apical membranes of fungiform papilla taste receptor cells. To avoid potential confounding effects of pharmacological interventions and to permit quantification of aggregate Na+ channel behavior using a kinetic model, we obtained chorda tympani nerve responses to NaCl and sodium gluconate (NaGlu) during receptive field voltage clamp in rats aged from 12–14 to 60 days and older (60+ days). Significant, age-dependent increases in chorda tympani responses to these stimuli occurred as expected. Importantly, apical Na+ channel density, estimated from an apical Na+ channel kinetic model, increased monotonically with age. The maximum rate of Na+response increase occurred between postnatal days 12–14 and 29–31. In addition, estimated Na+ channel affinity increased between 12–14 and 19–23 days of age, i.e., on a time course distinct from that of the maximum rate of Na+response increase. Finally, estimates of the fraction of clamp voltage dropped across taste receptor apical membranes decreased between 19–23 and 29–31 days of age for NaCl but remained stable for NaGlu. The stimulus dependence of this change is consistent with a developmental increase in taste bud tight junctional Cl− ion permeability that lags behind the developmental increase in apical Na+ channel density. A significant, indirect anion influence on apical Na+ channel properties was present at all ages tested. This influence was evident in the higher apparent apical Na+ channel affinities obtained for NaCl relative to NaGlu. This stimulus-dependent modulation of apical Na+ channel apparent affinity relies on differences in the transepithelial potentials between NaCl and NaGlu. These originate from differences in paracellular anion permeability but act also on the driving force for Na+ through apical Na+channels. Detection of such an influence on taste depends fundamentally on the preservation of taste bud polarity and on a direct measure of sensory function, such as the response of primary afferents.

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.

Gustatory changes in patients with chronic otitis media, before and after middle-ear surgery

2012 ◽  
Vol 126 (5) ◽  
pp. 470-474 ◽  
Author(s):  
C-C Huang ◽  
C-D Lin ◽  
C-Y Wang ◽  
J-H Chen ◽  
Y-T Shiao ◽  
...  
Keyword(s):  
Otitis Media ◽  
Middle Ear ◽  
Chronic Otitis Media ◽  
Middle Ear Surgery ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Ear Surgery ◽  
Taste Testing ◽  
Gustatory Function ◽  
Before And After

AbstractObjective:We investigated gustatory changes in patients with chronic otitis media, before and after middle-ear surgery.Methods:This prospective study included 38 patients with unilateral chronic otitis media. We used taste testing solutions to evaluate each patient's taste function. Intra-operative assessments of the chorda tympani nerve were also compared and analysed.Results:Patients with chronic otitis media had significantly worse ipsilateral perception of sour, bitter and salty tastes. In patients with good intra-operative preservation of the chorda tympani nerve, there was significant improvement in gustatory function one month post-operatively, compared with the pre-operative baseline. In patients who sustained intra-operative chorda tympani nerve injury, one month post-operative gustatory function was the same as the pre-operative baseline.Conclusion:Middle-ear surgery for chronic otitis media not only treats the ear but also improves gustatory function in the majority of patients. In patients with intra-operative injury to the chorda tympani nerve, post-operative taste decline is only temporary.

Enhanced membrane turnover in response to stimuli in the primate taste bud

1989 ◽  
Vol 47 ◽  
pp. 788-789
Author(s):  
Albert I. Farbman ◽  
Göran Hellekant
Keyword(s):  
Rhesus Monkeys ◽  
Nerve Impulse ◽  
Salivary Secretion ◽  
Taste Bud ◽  
Chorda Tympani ◽  
Chorda Tympani Nerve ◽  
Membrane Turnover ◽  
Fungiform Papilla ◽  
Thin Sections ◽  
Receptor Complexes

The presence of membrane-enclosed vesicles, 50-100 nm in diameter (cf. Fig. 1), has been observed in the taste pores of rats, mice, and rabbits, although little attention has been devoted to their importance. Murray has noted that fungiform papilla taste pores contained more vesicles than foliate papilla pores. In a recent paper we showed that thaumatin, an intensely sweet, basic protein (pl = 12), binds to the vesicles and to microvilli in taste pores. We suggested that the vesicles were shed from the microvilli as a kind of apocrine secretion, and proposed that the shedding of these vesicles may be an important means by which taste bud cells rid themselves of certain stimulus/receptor complexes, particularly when the stimulus is a large and/or highly charged molecule, such as thaumatin. To investigate this hypothesis further, we used electron microscopy to examine taste pores of both vallate and foliate papillae from Rhesus monkeys, before and after stimulation with thaumatin. We also recorded neural activity from the glossopharyngeal and chorda tympani nerves during stimulation with thaumatin and other tastants.Rhesus monkeys were anesthetized with ketamine and given glycopyrrolate to inhibit salivary secretion. Tongues were thoroughly rinsed and the region of the foliate or vallate papilla treated with thaumatin (33 mg/1) or sucrose (0.3M) for 5-10 min. After a brief rinse, papillae were removed surgically. Control papillae were biopsied with no stimulation. Specimens were fixed for 2 h in: 2% paraformaldehyde, 2% glutaraldehyde in phosphate buffer, pH 7.2, rinsed and post-fixed in phosphate-buffered 1% OsO4,dehydrated in ethanols, and embedded in Epon-Araldite. Thin sections were examined in a JEOL-100 CX electron microscope with particular attention to the contents of the taste pores. For neurophysiology, the glossopharyngeal or chorda tympani nerve was exposed, in anesthetized monkeys, by dissection, and electrodes were placed on the nerve. Impulse activity was recorded with a PAR 113 amplifier, monitored over a loudspeaker and an oscilloscope, and fed into a recorder together with the output from an integrator which indicated the type and time of stimulation. The tongue was stimulated with a system that delivers solutions at programmed intervals under conditions of constant flow and temperature. Each stimulation lasted 10 sec, followed by a 30 or 50 sec rinse before the next stimulus. Stimuli were 0.02M citric acid, 0.1 M NaCl, 0.3M sucrose and 33 mg/l thaumatin.

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.

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