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Burghardt GKL, Cuevas M, Sekine R, Hummel T. Trigeminal Sensitivity in Patients With Allergic Rhinitis and Chronic Rhinosinusitis. Laryngoscope 2023; 133:654-660. [PMID: 36504410 DOI: 10.1002/lary.30512] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 11/10/2022] [Accepted: 11/13/2022] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Allergic rhinitis (AR) and chronic rhinosinusitis with nasal polyps (CRSwNP) are of high importance in otorhinolaryngology. Some of their symptoms are related to changes in the nasal trigeminal sensitivity. The aim of this study was to compare nasal trigeminal sensitivity in patients with AR, CRSwNP, and healthy controls (HC). METHODS A total of 75 individuals participated (age 19-78 years; 34 AR, 10 CRSwNP and 31 HC). Olfactory function was determined using the extended Sniffin' Sticks test battery. Trigeminal sensitivity was assessed with CO2 detection thresholds. Trigeminal negative mucosal potentials (NMP) and EEG-derived event-related potentials (ERP) were recorded in response to selective olfactory (phenylethyl alcohol) and trigeminal (CO2 ) stimuli using high-precision air-dilution olfactometry. RESULTS In comparison to HC, AR patients had lower CO2 thresholds, also reflected in shorter peak latencies in NMP and trigeminal ERP measurements. CRSwNP patients had a decreased sensitivity for trigeminal stimuli, also reflected in prolonged trigeminal ERP latencies, and reduced olfactory function compared to HC. CONCLUSION AR patients seemed to be more sensitive to trigeminal stimuli than CRSwNP patients. Importantly, the differences could be shown on psychophysical and electrophysiological levels. The changes in trigeminal sensitivity appear to be present already at the level of the respiratory epithelium. The differences between the two groups may depend on the specific inflammatory changes accompanying each disorder, the degree of inflammatory activity, or duration of the inflammatory disorder. However, because the sample sizes are relatively small, these results need to be confirmed in the future studies with larger groups. LEVEL OF EVIDENCE 4 Laryngoscope, 133:654-660, 2023.
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Affiliation(s)
| | - Mandy Cuevas
- Smell and Taste Clinic, Department of Otorhinolaryngology, Technische Universität Dresden, Dresden, Germany
| | - Rumi Sekine
- Smell and Taste Clinic, Department of Otorhinolaryngology, Technische Universität Dresden, Dresden, Germany.,Department of Otorhinolaryngology, The Jikei University School of Medicine, Tokyo, Japan
| | - Thomas Hummel
- Smell and Taste Clinic, Department of Otorhinolaryngology, Technische Universität Dresden, Dresden, Germany
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Dalla Costa FA, Gibson TJ, Oliveira SEO, Gregory NG, Faucitano L, Dalla Costa OA. On-farm culling methods used for pigs. Anim Welf 2021. [DOI: 10.7120/09627286.30.3.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The culling of injured and non-viable pigs (Sus scrofa) (neonate to breeding stock) is a routine and necessary procedure on most farms. Usually, pigs are culled using one of the following methods: blunt-force trauma (manual and mechanical), captive-bolt stunners, electrical stunning
and electrocution or carbon dioxide. Manual blunt-force trauma is one of the most widely used methods due to its low or absent operational and investment costs. However, as a method, it has serious limitations, which include the risk of incomplete concussion, pain, and distress. Manual blunt-force
trauma is also aesthetically unpleasant to operators and wider society. To address these issues there has been significant recent research into the development of alternatives to manual blunt-force trauma, these include: captive-bolt stunners, on-farm, gas-based controlled atmosphere systems,
low atmospheric pressure systems and electrical stunning. Some of these are currently in commercial use while others are still in the developmental phase. This review brings together the relevant research in this field, evaluating the methods in terms of mechanism of action (mechanical and
physiological), effectiveness and animal welfare.
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Gudziol H, Guntinas-Lichius O. Electrophysiologic assessment of olfactory and gustatory function. HANDBOOK OF CLINICAL NEUROLOGY 2020; 164:247-262. [PMID: 31604551 DOI: 10.1016/b978-0-444-63855-7.00016-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This chapter reviews approaches for assessing human and gustatory function using electrophysiologic methods. Its focus is on changes in electrical signals, including summated generator potentials that occur after nasal or oral stimulation. In the first part of the review, we describe tools available to the clinician for assessing olfactory and nasotrigeminal function, including modern electroencephalography (EEG) analysis of brain responses both in the time domain and in the time-frequency (TF) domain. Particular attention is paid to chemosensory event-related potentials (CSERPs) and their potential use in medical-legal cases. Additionally, we focus on the changes of summated generator potentials from the olfactory and respiratory nasal epithelium that could provide new diagnostic insights. In the second part, we describe gustatory event-related potentials (gCSERPs) obtained using a relatively new computer controlled gustometer. A device for presenting different pulses of electrical current to the tongue is also described, with weaker pulses likely reflecting gCSERPs and stronger ones trigeminal CSERPs. Finally, summated generator potentials from the surface of the tongue during gustatory stimulation are described that may prove useful for examining peripheral taste function.
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Affiliation(s)
- Hilmar Gudziol
- Department of Otorhinolaryngology, University Hospital, Jena, Germany.
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Tremblay C, Emrich R, Cavazzana A, Klingelhoefer L, Brandt MD, Hummel T, Haehner A, Frasnelli J. Specific intranasal and central trigeminal electrophysiological responses in Parkinson's disease. J Neurol 2019; 266:2942-2951. [PMID: 31451911 DOI: 10.1007/s00415-019-09517-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 08/13/2019] [Accepted: 08/16/2019] [Indexed: 01/20/2023]
Abstract
Olfactory dysfunction is a frequent early non-motor symptom of Parkinson's disease (PD). There is evidence that with regard to trigeminal perception, PD-related olfactory dysfunction is different from other olfactory disorders. More specifically, trigeminal sensitivity, when measured behaviorally, was unimpaired in PD patients as opposed to patients with non-Parkinsonian olfactory dysfunction (NPOD). We sought to investigate the trigeminal pathway by measuring electrophysiological recordings from the nasal epithelium and EEG-derived event-related potentials in response to a specific trigeminal stimulus in 21 PD patients and compare them to 23 patients with NPOD and 25 controls (C). The peripheral trigeminal response, as measured by the negative-mucosa potential, showed no difference between patients with PD and controls whereas PD patients showed faster responses than patients with NPOD, the latter having shown slower and larger responses than controls (18 PD, 14 NPOD, 20 C). The central trigeminal response, as measured by event-related potentials, revealed larger early component response in PD patients compared to patients with NPOD (15 PD, 21 NPOD, 23 C). As expected, psychophysical olfactory testing showed impaired olfactory function in both groups of patients as opposed to controls. Discriminant analysis revealed a model that could predict group membership for 80% of participants based on the negative-mucosa potential latency, olfactory threshold and discrimination tests. These results provide novel insights into the pattern of trigeminal activation in PD which will help to differentiate PD-related olfactory loss from NPOD, a crucial step towards establishing early screening batteries for PD including smell tests.
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Affiliation(s)
- Cécilia Tremblay
- Research Chair in Chemosensory Neuroanatomy, Department of Anatomy, Université du Québec à Trois-Rivières (UQTR), Trois-Rivières, QC, Canada.
| | - Rosa Emrich
- Department of Otorhinolaryngology, Smell and Taste Clinic, Technical University of Dresden, Dresden, Germany
| | - Annachiara Cavazzana
- Department of Otorhinolaryngology, Smell and Taste Clinic, Technical University of Dresden, Dresden, Germany
| | | | - Moritz D Brandt
- Department of Neurology, TU Dresden, Dresden, Germany.,German Center for Neurodegenerative Diseases (DZNE), Dresden, Germany
| | - Thomas Hummel
- Department of Otorhinolaryngology, Smell and Taste Clinic, Technical University of Dresden, Dresden, Germany
| | - Antje Haehner
- Department of Otorhinolaryngology, Smell and Taste Clinic, Technical University of Dresden, Dresden, Germany
| | - Johannes Frasnelli
- Research Chair in Chemosensory Neuroanatomy, Department of Anatomy, Université du Québec à Trois-Rivières (UQTR), Trois-Rivières, QC, Canada.,Research Center of the Sacré-Cœur Hospital, Montréal, QC, Canada
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Chisholm JM, Pang DSJ. Assessment of Carbon Dioxide, Carbon Dioxide/Oxygen, Isoflurane and Pentobarbital Killing Methods in Adult Female Sprague-Dawley Rats. PLoS One 2016; 11:e0162639. [PMID: 27648836 PMCID: PMC5029904 DOI: 10.1371/journal.pone.0162639] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 08/25/2016] [Indexed: 11/26/2022] Open
Abstract
Background Exposure to carbon dioxide (CO2) gas as a killing method is aversive and exposure to high concentrations is likely to be painful. Bradycardia during exposure to CO2 is associated with nociception and pain. However, it is unclear if bradycardia occurs before loss of consciousness as definitions of loss of consciousness vary in the literature. The objectives of this study were to explore the relationship between recumbency, loss of righting reflex (LORR) and a quiescent electromyograph as measures of loss of consciousness, and identify the onset of bradycardia in relation to these measures. Our primary hypothesis was that CO2 exposure would result in bradycardia, which would precede LORR. Methods Thirty-two adult, female Sprague-Dawley rats were instrumented with a telemetry device and randomly assigned to one of four killing methods (concentrations of 100% CO2, CO2 (70%)/O2 (30%), isoflurane (5%) and intraperitoneal pentobarbital (200 mg/kg). Time to achieve recumbency, LORR, quiescent electromyograph, isoelectric electrocorticograph, heart rate and apnea were recorded. Results The general order of progression was recumbency, LORR, quiescent electromyograph, isoelectric electrocorticograph and apnea. Recumbency preceded LORR in the majority of animals (CO2; 7/8, CO2/O2; 8/8, isoflurane; 5/8, pentobarbital; 4/8). Bradycardia occurred before recumbency in the CO2 (p = 0.0002) and CO2/O2 (p = 0.005) groups, with a 50% reduction in heart rate compared to baseline. The slowest (time to apnea) and least consistent killing methods were CO2/O2 (1180 ± 658.1s) and pentobarbital (875 [239 to 4680]s). Conclusion Bradycardia, and consequently nociception and pain, occurs before loss of consciousness during CO2 exposure. Pentobarbital displayed an unexpected lack of consistency, questioning its classification as an acceptable euthanasia method in rats.
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Affiliation(s)
- Jessica M Chisholm
- Department of Veterinary Clinical and Diagnostic Sciences, University of Calgary, Alberta, Canada, s
| | - Daniel S J Pang
- Department of Veterinary Clinical and Diagnostic Sciences, University of Calgary, Alberta, Canada, s.,Hotchkiss Brain Institute, University of Calgary, Alberta, Canada
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Testing three measures of mouse insensibility following induction with isoflurane or carbon dioxide gas for a more humane euthanasia. Appl Anim Behav Sci 2015. [DOI: 10.1016/j.applanim.2014.11.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Intranasal trigeminal sensitivity: measurements before and after nasal surgery. Eur Arch Otorhinolaryngol 2013; 271:87-92. [PMID: 23568039 DOI: 10.1007/s00405-013-2466-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Accepted: 03/20/2013] [Indexed: 10/27/2022]
Abstract
Nasal surgeries constitute an extensive manipulation of the nasal mucosa and therefore of structures related to trigeminal and olfactory sensitivity. While olfactory changes due to nasal surgery are relatively well investigated, there are only very few studies regarding trigeminal sensitivity. Aim of the present study was to investigate sensory changes after nasal surgery with special regard to the trigeminal sensitivity. In 38 patients prior to and around 12 weeks after nasal surgery the following psychophysical measures were performed: odor identification, odor discrimination, phenyl ethyl alcohol odor threshold, sensitivity to trigeminal stimuli, trigeminal detection thresholds and trigeminal pain thresholds. These results were compared to those of a control group (43 healthy volunteers). Psychophysical olfactory and trigeminal testing showed no major changes in patients after surgery compared to the control group. Independent from the time of measurement higher trigeminal detection thresholds were found in patients compared to healthy subjects, meaning that trigeminal thresholds were already increased before surgery. The present study revealed a decreased trigeminal sensitivity in patients already before surgery. It may be hypothesized that patients also exhibit a decreased sensitivity for nasal airflow, which may also contribute to the patients' impression of impaired nasal breathing.
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Melzner J, Bitter T, Guntinas-Lichius O, Gottschall R, Walther M, Gudziol H. Comparison of the orthonasal and retronasal detection thresholds for carbon dioxide in humans. Chem Senses 2011; 36:435-41. [PMID: 21398414 DOI: 10.1093/chemse/bjr013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Several studies have investigated the orthonasal detection threshold for carbon dioxide (CO(2)) in humans. The aim of current study was to investigate whether 24 healthy young subjects exhibited differences of CO(2) detection thresholds during orthonasal or retronasal stimulation. As nasal mucosa is believed to desensitize to CO(2) concentrations at or below 4% (v/v) during expiration, the second aim of the study was to explore the influence during nasal versus oral breathing on the detection thresholds. CO(2) stimuli of varying concentrations and a duration of 1000 ms were applied with an air-dilution olfactometer in either the anterior nasal cavity or the nasopharynx during nasal respectively oral breathing. In these 4 conditions, the mean CO(2) detection thresholds using the staircase forced-choice procedure were between 3.9% and 5.3% (v/v). Statistical analysis revealed a significant difference between orthonasal and retronasal stimulation. The CO(2) detection threshold was lower in retronasal stimulation. The nasopharyngeal mucosa is more sensitive to perithreshold CO(2) stimuli than the nasal mucosa. The breathing route had no influence on the detection thresholds. The results of this study indicate that the natural contact of the nasal mucosa with approximately 4% (v/v) CO(2) during nasal expiration does not influence CO(2) detection thresholds.
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Affiliation(s)
- Johannes Melzner
- Department of Otorhinolaryngology, University Hospital Jena, Germany.
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Zernecke R, Kleemann A, Haegler K, Albrecht J, Vollmer B, Linn J, Bruckmann H, Wiesmann M. Chemosensory Properties of Human Sweat. Chem Senses 2009; 35:101-8. [DOI: 10.1093/chemse/bjp087] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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Silver WL, Finger TE. The anatomical and electrophysiological basis of peripheral nasal trigeminal chemoreception. Ann N Y Acad Sci 2009; 1170:202-5. [PMID: 19686138 DOI: 10.1111/j.1749-6632.2009.03894.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The trigeminal nerve (TN) provides sensory information from the eyes, nose, and mouth. A subset of trigeminal nerve fibers, particularly those containing the neuropeptides substance P and calcitonin gene-related peptide (CGRP), responds to chemical irritants in the environment. Axons in the ethmoid and nasopalatine branches of the trigeminal nerve innervate the nasal mucosa where they ramify repeatedly. TN endings extend close to the nasal epithelial surface stopping at the line of tight junctions only a few micrometers from the surface. A single ethmoid nerve axon may send branches to the nasal mucosa, olfactory bulb, and the spinal trigeminal complex. Traditionally, irritants are thought to stimulate free TN endings in the nasal epithelium. Recently, however, solitary chemoreceptor cells (SCCs) have been found scattered throughout the nasal cavity. The SCCs are contacted by TN fibers and may express T2R ''bitter-taste'' receptors alpha-gustducin, and TRPM5. Peripheral trigeminal electrophysiological recordings in response to irritants have been obtained from the mucosa (negative mucosal potential, NMP) and the nerve to analyze characteristics of trigeminal stimuli. Responses to a wide variety of irritants have been recorded from the ethmoid nerve. In general, the more lipid soluble the compound, the lower the threshold. Nerve recordings have also suggested several mechanisms by which irritants elicit responses. Bitter substances elicit responses from the ethmoid nerve and cause a change in respiration indicating stimulation via SCCs. SCCs themselves respond to chemical stimuli and may be contributing to the detection of nasal irritants.
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Affiliation(s)
- Wayne L Silver
- Department of Biology, Wake Forest University, Winston-Salem, North Carolina 27109, USA.
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Abstract
The trigemino-cardiac reflex (TCR) is clinically defined as the sudden onset of parasympathetic activity, sympathetic hypotension, apnea, or gastric hypermotility during central or peripheral stimulation of any of the sensory branches of the trigeminal nerve. Clinically, the TCR has been reported to occur during craniofacial surgery, manipulation of the trigeminal nerve/ganglion and during surgery for lesion in the cerebellopontine angle, cavernous sinus, and the pituitary fossa. Apart from the few clinical reports, the physiologic function of this brainstem reflex has not yet been fully explored. The manifestation of the TCR can vary from bradycardia and hypotension to asystole. From the experimental findings, the TCR represents an expression of a central reflex leading to rapid cerebrovascular vasodilatation generated from excitation of oxygen-sensitive neurons in the rostral ventro-lateral medulla oblongata. By this physiologic response, the systemic and cerebral circulations may be adjusted in a way that augments cerebral perfusion. This review summarizes the current state of knowledge about TCR.
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Ferris KE, Clark RD, Coates EL. Topical inhibition of nasal carbonic anhydrase affects the CO2 detection threshold in rats. Chem Senses 2007; 32:263-71. [PMID: 17215338 DOI: 10.1093/chemse/bjl054] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Previous studies indicate that Long-Evans rats can be operantly trained to discriminate inspired CO(2) concentrations as low as 0.5%. This ability has been proposed to be due to the presence of CO(2)-sensitive olfactory receptors that contain the enzyme carbonic anhydrase (CA). The objectives of the present study were as follows: 1) to determine whether Zucker rats could be operantly conditioned to discriminate low concentrations of CO(2) from control air and 2) to determine the rats' CO(2) detection thresholds before and after nasal perfusion of mammalian Ringers or methazolamide, a CA inhibitor. Rats were operantly trained to discriminate between 25% CO(2) and control air (0% CO(2)) and were then subjected to various CO(2) concentrations (0.5-12.5%) to determine their CO(2) detection thresholds. The average (+/-standard error of mean) baseline CO(2) detection threshold of 7 Zucker rats was 0.48 +/- 0.07% CO(2), whereas the average CO(2) detection thresholds after nasal perfusion of either mammalian Ringers or 10(-2) M methazolamide were 1.41 +/- 0.30% and 5.92 +/- 0.70% CO(2), respectively. The average CO(2) detection threshold after methazolamide was significantly greater (P<0.0001) than the baseline detection threshold. These findings demonstrate that like Long-Evans rats, Zucker rats can be trained to discriminate low concentrations of CO(2) and that inhibition of nasal CA reduces the ability of the rats to detect low concentrations (3.5% and below) but not higher concentrations of CO(2) (12.5%). These results add to the growing evidence that olfactory neurons exhibiting CA activity are CO(2) chemoreceptors sensitive to physiological concentrations of CO(2).
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Scheibe M, Zahnert T, Hummel T. Topographical differences in the trigeminal sensitivity of the human nasal mucosa. Neuroreport 2006; 17:1417-20. [PMID: 16932150 DOI: 10.1097/01.wnr.0000224764.61959.e8] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The aim of the study was to investigate differences in the distribution of intranasal trigeminal receptors in humans using an electrophysiological measure of trigeminally induced activation, the negative mucosa potential. A total of 29 young, healthy volunteers participated, results were on the basis of data from 18 participants. The trigeminal irritant CO2 was presented using a computer-controlled olfactometer. Negative mucosa potential recording sites included the anterior olfactory cleft, the anterior septum, and the lower turbinate. Lowest amplitudes of the negative mucosa potential were found in the olfactory cleft, maximum amplitudes at the septum. Intranasal measurements of CO2 concentrations suggested that these differences were not due to the intranasal distribution of CO2. These results are compatible with the idea that the trigeminal system acts as a sentinel of the human airways.
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Affiliation(s)
- Mandy Scheibe
- Smell & Taste Clinic, Department of Otorhinolaryngology, University of Dresden Medical School, Dresden, Germany
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Thuerauf N, Lunkenheimer J, Lunkenheimer B, Sperling W, Bleich S, Schlabeck M, Wiltfang J, Kornhuber J. Memantine fails to facilitate partial cigarette deprivation in smokers – no role of Memantine in the treatment of nicotine dependency? J Neural Transm (Vienna) 2006; 114:351-7. [PMID: 17043926 DOI: 10.1007/s00702-006-0570-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2006] [Accepted: 08/07/2006] [Indexed: 12/20/2022]
Abstract
The efficacy of Memantine in the treatment of nicotine dependency in humans remained to be evaluated. The aims of our pilot study were to investigate (1) the effectiveness of Memantine in facilitating smoking reduction and (2) the influence of Memantine on the perception of nicotine. In order to achieve these aims we conducted a placebo controlled double-blind parallel group study in smokers (n = 20 per group). Before the beginning of the treatment-phase (10/20 mg Memantine per day) all participants were instructed to reduce smoking (partial deprivation). Before and during partial deprivation we registered the daily cigarette consumption and craving estimates. Following nasal stimulation with nicotine enantiomers hedonic and intensity estimates and the discrimination ability were assessed. Memantine failed to facilitate smoking reduction and did not influence the perception of nicotine with the exception of a weak reduction of olfactory intensity estimates reaching statistical significance for one nicotine enantiomer only.
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Affiliation(s)
- N Thuerauf
- Department of Psychiatry and Psychotherapy, University of Erlangen-Nürnberg, Erlangen, Germany.
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Thuerauf N, Markovic K, Braun G, Bleich S, Reulbach U, Kornhuber J, Lunkenheimer J. The influence of mecamylamine on trigeminal and olfactory chemoreception of nicotine. Neuropsychopharmacology 2006; 31:450-61. [PMID: 16123771 DOI: 10.1038/sj.npp.1300842] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Nicotine presented to the nasal cavity at low concentrations evokes 'odorous' sensations, and at higher concentrations 'burning' and 'stinging' sensations. A study in smokers and nonsmokers provided evidence of a relationship between the experience with the pharmacological action of S-(-)-nicotine and the perceived pleasantness/unpleasantness following nasal stimulation with S-(-)-nicotine. Mecamylamine, a nicotinic acetylcholine-receptor-(nAch-R) antagonist, was able to block painful responses following chemical stimulation of the human tongue and to block responses from the rat's ethmoidal nerve. The aim of our study in humans was to investigate the effects of mecamylamine on the olfactory and the trigeminal chemoreception of nicotine enantiomers. In order to achieve this aim, we determined-before and after mecamylamine-(1) detection thresholds, trigeminal thresholds, and intensity estimates (stimulus intensity) and (2) recorded the negative mucosal potential (NMP) following nasal stimulation with nicotine in a placebo-controlled double blind study (n = 15). CO(2) was used as a trigeminal and H(2)S as an olfactory control stimulus. Mecamylamine significantly increased trigeminal thresholds of S-(-)-nicotine and reduced intensity estimates and NMPs following stimulation with nicotine enantiomers, whereas mecamylamine did not influence NMPs and trigeminal intensity estimates following stimulation with CO(2). In contrast, mecamylamine did neither influence detection thresholds nor olfactory intensity estimates following stimulation with olfactory nicotine concentrations. These results demonstrate that the trigeminal nasal chemoreception of nicotine enantiomers, in contrast to CO(2), is mediated by nAch-Receptors and give evidence that the olfactory chemoreception of nicotine is independent from peripheral nAch-Receptors.
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Affiliation(s)
- Norbert Thuerauf
- Sensory Research Unit, Department of Psychiatry, University of Erlangen-Nuremberg, Bavaria, Germany.
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Frasnelli J, Hummel T. Intranasal trigeminal thresholds in healthy subjects. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2005; 19:575-580. [PMID: 21783529 DOI: 10.1016/j.etap.2004.12.022] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
The trigeminal chemosensory system responds to irritation of the nasal cavity. Despite its dominant role as a sentinel in protecting the respiratory tract from harmful substances and its involvement in the perception of odorous substances, it has received relatively little attention compared to the olfactory system. Aim of the present study was the comparison of two psychophysical techniques to assess intranasal trigeminal thresholds, namely (A) responses of subjects who focused on intranasal trigeminally mediated sensations, and (B) the ability of subjects to identify the side of the nose receiving unilaterally presented stimuli. Method A (0.81>r>0.56) was found to show a higher test-retest reliability than Method B (0.48>r>0.40). Method A revealed thresholds that were approximately 32 times lower than those measured with method B. With method A women were found to have lower thresholds than men; no such difference could be detected between older and younger subjects. In conclusion, if the objective is to assess the level at which trigeminal sensations are detected with the utmost objectivity and unconfounded by smell, the obvious choice is B. If one's purpose is to assess the level at which trigeminal sensations are detected and the quality perceived, in the context of an odor one might opt for Method A. Thus, preference of one method over the other may depend on the question being asked, provided a well-instructed/trained panel of subjects is used.
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Affiliation(s)
- Johannes Frasnelli
- Smell and Taste Clinic, Department of Otorhinolaryngology, University of Dresden Medical School, Fetscherstrasse 74, 01307 Dresden, Germany
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Frasnelli J, Hummel T. Age-related decline of intranasal trigeminal sensitivity: is it a peripheral event? Brain Res 2003; 987:201-6. [PMID: 14499964 DOI: 10.1016/s0006-8993(03)03336-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Compared to younger subjects, older people have a reduced sensitivity of the intranasal trigeminal system which responds to irritation of the nasal cavity. It is unclear whether the cause of this difference relates to age-dependent changes in the periphery of the system. The aim of the present study was the comparison of intranasal trigeminal thresholds assessed through electrophysiological measurements in eight young (four women, four men; mean age 25 years) and eight older subjects (four women, four men; mean age 62 years). The negative mucosa potential (NMP), a peripheral correlate of trigeminal activation, was recorded from the nasal mucosa in response to stimulation with varying concentrations of the mixed olfactory/trigeminal stimulants menthol and linalool. Thresholds were estimated as the strongest concentration which did not elicit a NMP response. Older subjects were found to have higher thresholds for menthol when compared to younger subjects. Furthermore, an explorative analysis indicated that the increase of response amplitudes to increasing stimulus concentrations was shallower in older subjects. These findings indicate that age related loss of intranasal trigeminal sensitivity seems to take place, at least to some degree, in the periphery of the intranasal trigeminal system.
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Affiliation(s)
- Johannes Frasnelli
- Smell and Taste Clinic, Department of Otorhinolaryngology, University of Dresden Medical School, Fetscherstr. 74, 01307 Dresden, Germany
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