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Karasawa M, Yokouchi K, Kakegawa A, Kawagishi K, Moriizumi T, Fukushima N. Effect of graded nerve pressure injuries on motor function. J Neurosurg 2015; 122:1438-43. [PMID: 25748301 DOI: 10.3171/2014.9.jns141451] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECT The purpose of this study was to determine the minimum amount of nerve fibers required to maintain normal motor function after nerve injury in rats. METHODS The authors first confirmed that a common peroneal nerve injury caused more aggravating effects on lower limb motor function than tibial nerve injury, as assessed by the static sciatic index (SSI). Thereafter, rats were subjected to varying degrees of crush injury to the common peroneal nerve. At 48 hours after the injury, motor function was assessed using the SSI and slope-walking ability (with slope angles of 30° and 45°). The tibialis anterior muscle, a main muscle innervated by the common peroneal nerve, was removed. Muscle sections were co-labeled with neuronal class III β-tubulin polyclonal antibody to identify the presence of axons and Alexa Fluor 488-conjugated α-bungarotoxin to identify the presence of motor endplates. RESULTS The evaluation of neuromuscular innervation showed a correlation between SSI scores and ratios of residual axons (rs = 0.68, p < 0.01), and there was a statistically significant difference between slope-walking ability and ratios of residual axons (p < 0.01). Moreover, the ratios of residual axons in the nerve-crushed rats with normal motor function (SSI above -20) ranged from 36.5% to 88.7%, and those ratios in the success group with slope-walking angles of 30° and 45° ranged from 14.7% to 88.7% and from 39.8% to 88.7%, respectively. CONCLUSIONS In this study of rodents, less than half of the motor axons were sufficient to maintain normal motor function of the lower limb.
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Affiliation(s)
- Mika Karasawa
- Department of Anatomy, Shinshu University School of Medicine, Matsumoto, Japan
| | - Kumiko Yokouchi
- Department of Anatomy, Shinshu University School of Medicine, Matsumoto, Japan
| | - Akira Kakegawa
- Department of Anatomy, Shinshu University School of Medicine, Matsumoto, Japan
| | - Kyutaro Kawagishi
- Department of Anatomy, Shinshu University School of Medicine, Matsumoto, Japan
| | - Tetsuji Moriizumi
- Department of Anatomy, Shinshu University School of Medicine, Matsumoto, Japan
| | - Nanae Fukushima
- Department of Anatomy, Shinshu University School of Medicine, Matsumoto, Japan
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Kawagishi K, Ando M, Yokouchi K, Sumitomo N, Karasawa M, Fukushima N, Moriizumi T. Stereological quantification of olfactory receptor neurons in mice. Neuroscience 2014; 272:29-33. [PMID: 24797329 DOI: 10.1016/j.neuroscience.2014.04.050] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Revised: 04/21/2014] [Accepted: 04/21/2014] [Indexed: 11/27/2022]
Abstract
The total number of olfactory receptor neurons (ORNs) in the mouse main olfactory epithelium (MOE) was estimated using stereological sampling. Noses and skulls of male and female 8-week-old C57BL/6J mice were de-calcified, embedded in paraffin, cut into 10-μm-thick sections serially at 100-μm intervals, and processed for immunohistochemistry for the olfactory marker protein (OMP), a specific marker for ORNs. The number of OMP (+) receptor neurons was measured using an optical fractionator with the Stereo-Investigator software. The mean values of the total number of OMP (+) receptor neurons in the unilateral MOE were 5,140,000±380,000 in males and 5,210,000±380,000 in females, with no significant differences between the sexes. We concluded that the total number of ORNs in the unilateral MOE is approximately 5×10(6) in mice.
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Affiliation(s)
- K Kawagishi
- Department of Anatomy, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621, Japan.
| | - M Ando
- Department of Anatomy, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621, Japan
| | - K Yokouchi
- Department of Anatomy, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621, Japan
| | - N Sumitomo
- Department of Anatomy, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621, Japan
| | - M Karasawa
- Department of Anatomy, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621, Japan
| | - N Fukushima
- Department of Anatomy, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621, Japan
| | - T Moriizumi
- Department of Anatomy, Shinshu University School of Medicine, 3-1-1 Asahi, Matsumoto, Nagano 390-8621, Japan
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Hirayama S, Kawagishi K, Yokouchi K, Fukushima N, Karasawa M, Moriizumi T. Regenerative Capacity of Bulbar Projection Neurons During Development: A Quantitative Neuronal Analysis With Functional Correlation. Chem Senses 2013; 39:47-56. [DOI: 10.1093/chemse/bjt053] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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4
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Functional correlation between olfaction and various sectioning of the lateral olfactory tract. Neurosci Res 2012; 73:17-23. [DOI: 10.1016/j.neures.2012.02.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Revised: 02/03/2012] [Accepted: 02/13/2012] [Indexed: 11/19/2022]
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5
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Re-evaluation of spontaneous regeneration of the lateral olfactory tract. Neurosci Res 2010; 68:15-21. [DOI: 10.1016/j.neures.2010.05.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2010] [Revised: 05/06/2010] [Accepted: 05/20/2010] [Indexed: 11/22/2022]
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Kawagishi K, Yokouchi K, Fukushima N, Sakamoto M, Sumitomo N, Moriizumi T. Determination of functionally essential neuronal population of the olfactory epithelium for nipple search and subsequent suckling behavior in newborn rats. Brain Res 2009; 1276:50-7. [PMID: 19393636 DOI: 10.1016/j.brainres.2009.04.032] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2008] [Revised: 03/19/2009] [Accepted: 04/13/2009] [Indexed: 11/29/2022]
Abstract
Neuronal population of the olfactory epithelium required for nipple search and subsequent suckling behavior was examined in newborn rats. After unilateral ablation of the olfactory bulb, different concentrations of ZnSO(4) were contralaterally injected into the nasal cavity to produce varying degrees of neuronal degeneration in the olfactory epithelium. The ZnSO(4)-treatment resulted in two populations of pups. One exhibited suckling while the other did not, and intact olfactory receptor neurons were quantified immunohistochemically using an antibody for olfactory marker protein (OMP), a marker protein for olfactory receptor neurons. The total numbers of the OMP (+) cells in the ZnSO(4)-treated pups with suckling capability ranged between 2457 and 4615, whereas those in the ZnSO(4)-treated pups without suckling capability ranged between 112 and 2398. With the mean value (4969) of the total numbers of the OMP (+) cells of the normal/control pups assumed to represent 100%, the total numbers of the OMP (+) cells accounted for 49-93% in the suckling (+) group and 2-48% in the suckling (-) group. From these findings, we conclude that approximately 50% of neuronal population of the olfactory epithelium is a critical value to distinguish between the two groups with and without suckling capability in the unilateral olfactory system of newborn rats.
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Affiliation(s)
- Kyutaro Kawagishi
- Department of Anatomy, Shinshu University School of Medicine, Matsumoto, Nagano 390-8621, Japan.
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Shiga H, Kinoshita Y, Washiyama K, Ogawa D, Amano R, Hirota K, Tsukatani T, Furukawa M, Miwa T. Odor detection ability and thallium-201 transport in the olfactory nerve of traumatic olfactory-impaired mice. Chem Senses 2008; 33:633-7. [PMID: 18534997 DOI: 10.1093/chemse/bjn030] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Although olfactory nerve damage is a contributing factor in the diagnosis of posttraumatic olfactory loss, at present, there are no methods to directly assess injury to these nerves. We have shown that following olfactory nerve injury in mice, thallium-201 (201 Tl) transport from the nasal cavity to the olfactory bulb decreases. To determine if olfactory function after nerve injury could be assessed with nasal administration of 201 Tl, we measured the correlation between odor detection ability (ODA) and the rate of transport of 201 Tl in olfactory nerves. Both ODA and 201 Tl transport were measured after bilateral olfactory nerve transection for a 4-week period. Cycloheximide solution was used for ODA against tap water. 201 Tl transport was measured as the ratio of radioactivity in the nasal cavity and olfactory bulb with gamma spectrometry. There was a significant correlation between ODA and the rate of 201 Tl transport in the olfactory nerve. These findings suggest that olfactory function after nerve injury can be objectively evaluated with the nasal administration of 201 Tl.
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Affiliation(s)
- Hideaki Shiga
- Department of Otorhinolaryngology, Graduate School of Medical Science, Kanazawa University, 13-1 Takaramachi, Kanazawa, Ishikawa 920, Japan.
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8
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Hettinger TP, Formaker BK, Frank ME. Cycloheximide: no ordinary bitter stimulus. Behav Brain Res 2007; 180:4-17. [PMID: 17400304 PMCID: PMC1995601 DOI: 10.1016/j.bbr.2007.02.027] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2006] [Revised: 02/09/2007] [Accepted: 02/15/2007] [Indexed: 01/08/2023]
Abstract
Cycloheximide (CyX), a toxic antibiotic with a unique chemical structure generated by the actinomycete, Streptomyces griseus, has emerged as a primary focus of studies on mammalian bitter taste. Rats and mice avoid it at concentrations well below the thresholds for most bitter stimuli and T2R G-protein-coupled receptors specific for CyX with appropriate sensitivity are identified for those species. Like mouse and rat, golden hamsters, Mesocricetus auratus, also detected and rejected micromolar levels of CyX, although 1mM CyX failed to activate the hamster chorda tympani nerve. Hamsters showed an initial tolerance for 500microM CyX, but after that, avoidance of CyX dramatically increased, plasticity not reported for rat or mouse. As the hamster lineage branches well before division of the mouse-rat lineage in evolutionary time, differences between hamster and mouse-rat reactions to CyX are not surprising. Furthermore, unlike hamster LiCl-induced learned aversions, the induced CyX aversion neither specifically nor robustly generalized to other non-ionic bitter stimuli; and unlike adverse reactions to other chemosensory stimuli, aversions to CyX were not mollified by adding a sweetener. Thus, CyX is unlike other bitter stimuli. The gene for the high-affinity CyX receptor is a member of a cluster of five orthologous T2R genes that are likely rodent-specific; this "CyX clade" is found in the mouse, rat and probably hamster, but not in the human or rabbit genome. The rodent CyX-T2R interaction may be one of multiple lineage-specific stimulus-receptor interactions reflecting a response to a particular environmental toxin. The combination of T2R multiplicity, species divergence and gene duplication results in diverse ligands for multiple species-specific T2R receptors, which confounds definition of 'bitter' stimuli across species.
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Affiliation(s)
- Thomas P Hettinger
- Center for Neurosciences, Department of Oral Health & Diagnostic Sciences, School of Dental Medicine, University of Connecticut Health Center, Farmington, CT 06030, United States.
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Walz A, Omura M, Mombaerts P. Development and topography of the lateral olfactory tract in the mouse: imaging by genetically encoded and injected fluorescent markers. ACTA ACUST UNITED AC 2006; 66:835-46. [PMID: 16673392 DOI: 10.1002/neu.20266] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In mammals, conventional odorants are detected by OSNs located in the main olfactory epithelium of the nose. These neurons project their axons to glomeruli, which are specialized structures of neuropil in the olfactory bulb. Within glomeruli, axons synapse onto dendrites of projection neurons, the mitral and tufted (M/T) cells. Genetic approaches to visualize axons of OSNs expressing a given odorant receptor have proven very useful in elucidating the organization of these projections to the olfactory bulb. Much less is known about the development and connectivity of the lateral olfactory tract (LOT), which is formed by axons of M/T cells connecting the olfactory bulb to central neural regions. Here, we have extended our genetic approach to mark M/T cells of the main olfactory bulb and their axons in the mouse, by targeted insertion of IRES-tauGFP in the neurotensin locus. In NT-GFP mice, we find that M/T cells of the main olfactory bulb mature and project axons as early as embryonic day 11.5. Final innervation of central areas is accomplished before the end of the second postnatal week. M/T cell axons that originate from small defined areas within the main olfactory bulb, as visualized by localized injections of fluorescent tracers in wild-type mice at postnatal days 1 to 3, follow a dual trajectory: a branch of tightly packed axons along the dorsal aspect of the LOT, and a more diffuse branch along the ventral aspect. The dorsal, but not the ventral, subdivision of the LOT exhibits a topographical segregation of axons coming from the dorsal versus ventral main olfactory bulb. The NT-GFP mouse strain should prove useful in further studies of development and topography of the LOT, from E11.5 until 2 weeks after birth.
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Affiliation(s)
- Andreas Walz
- The Rockefeller University, New York, New York 10021, USA
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10
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Rinberg D, Koulakov A, Gelperin A. Speed-Accuracy Tradeoff in Olfaction. Neuron 2006; 51:351-8. [PMID: 16880129 DOI: 10.1016/j.neuron.2006.07.013] [Citation(s) in RCA: 212] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2005] [Revised: 06/12/2006] [Accepted: 07/18/2006] [Indexed: 11/28/2022]
Abstract
The basic psychophysical principle of speed-accuracy tradeoff (SAT) has been used to understand key aspects of neuronal information processing in vision and audition, but the principle of SAT is still debated in olfaction. In this study we present the direct observation of SAT in olfaction. We developed a behavioral paradigm for mice in which both the duration of odorant sampling and the difficulty of the odor discrimination task were controlled by the experimenter. We observed that the accuracy of odor discrimination increases with the duration of imposed odorant sampling, and that the rate of this increase is slower for harder tasks. We also present a unifying picture of two previous, seemingly disparate experiments on timing of odorant sampling in odor discrimination tasks. The presence of SAT in olfaction provides strong evidence for temporal integration in olfaction and puts a constraint on models of olfactory processing.
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Affiliation(s)
- Dmitry Rinberg
- Monell Chemical Senses Center, 3500 Market Street, Philadelphia, Pennsylvania 19104, USA.
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11
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Kakegawa A, Yokouchi K, Fukushima N, Fukuyama T, Moriizumi T. Motor neurons essential for normal sciatic function in neonatally nerve-injured rats. Neuroreport 2006; 17:1149-52. [PMID: 16837844 DOI: 10.1097/01.wnr.0000230502.47973.fe] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The present study was aimed to determine neuronal population essential for normal motor function in young adult rats receiving various degrees of crushing to the sciatic nerve at the neonatal stage. Motor function was estimated by the static sciatic index, and a neuronal tracer was applied to the common peroneal nerve. The total numbers of the tracer-labeled neurons of the nerve-crushed rats were 74-383 in the normal function group, 14-61 in the disordered function group, and 0-32 in the severely disordered function group. We conclude that normal motor function can be well preserved by a very small population of motor neurons (approximately 15% of the control value) in the neonatally sciatic nerve-injured rats.
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Affiliation(s)
- Akira Kakegawa
- Department of Anatomy, Shinshu University School of Medicine, Matsumoto, Nagano, Japan
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12
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Yamatani H, Sato Y, Fujisawa H, Hirata T. Chronotopic organization of olfactory bulb axons in the lateral olfactory tract. J Comp Neurol 2004; 475:247-60. [PMID: 15211465 DOI: 10.1002/cne.20155] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The arrangement of axons in a tract can have a specific effect on the organization of functional neuronal circuits. Here we describe olfactory bulb axons chronologically arranged in the lateral olfactory tract. Newly differentiated projection neurons over the whole olfactory bulb are similarly marked with transient expression of c-kit protein. Their axons are assembled together and project into the ventral superficial part of the tract, displacing the older axons. This special assembly of the axons explains the nontopographic relationships between the olfactory bulb and the lateral olfactory tract axons that have been described in previous studies and could possibly influence the subsequent selection of the olfactory target areas by these axons.
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Affiliation(s)
- Hitoshi Yamatani
- Division of Brain Function, National Institute of Genetics, Graduate University for Advanced Studies, Yata 1111, Mishima 411-8540, Japan
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Koyama J, Yokouchi K, Fukushima N, Kawagishi K, Moriizumi T. Great potentiality of neonatal facial motor neurons for neural plasticity as determined by functionally essential neuronal population. Neurosci Res 2003; 46:85-93. [PMID: 12725915 DOI: 10.1016/s0168-0102(03)00033-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The present study was undertaken to determine the neuronal population essential for normal and minimal facial function of young adult rats that had received various degrees of crush injuries to the facial nerve in the neonatal period. Using a neuronal tracer, it was found in young adult rats receiving neonatal injuries that the minimum number of tracer-labeled facial motor neurons necessary for normal facial function corresponded to 13-14% of the neurons (2540+/-64) of the age-matched control animals, whereas the minimum number of neurons necessary for minimal facial function corresponded to 5%. On the other hand, the minimum numbers of tracer-labeled facial motor neurons necessary for normal and minimal facial function of young adult rats that received various degrees of crush injuries corresponded to 61 and 27-30%, respectively, of the neurons (2540+/-64) of the uninjured control animals. These results indicate that the facial function of animals with nerves crushed at the neonatal stage can be adequately maintained by a very small population of neurons, implying a great potential of neonatal neurons for neural plasticity.
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Affiliation(s)
- J Koyama
- Department of Neurosurgery, Shinshu University School of Medicine, Matsumoto 390-8621, Japan
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Kobayashi S, Koyama J, Yokouchi K, Fukushima N, Oikawa S, Moriizumi T. Functionally essential neuronal population of the facial motor nucleus. Neurosci Res 2003; 45:357-61. [PMID: 12631471 DOI: 10.1016/s0168-0102(02)00231-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Cranial nerve impairment is one of the more serious complications in neurosurgery. Nevertheless, the important question of how many neurons are required for cranial nerve functions remains unanswered. The VIIth cranial nerve (facial nerve) in mice was subjected to graded crush injuries. After assessment of the facial function, the number of uninjured, healthy facial motor neurons was quantified with a retrograde neuronal tracer. We report that normal facial function is preserved if intact neurons account for more than 56% of the control value, while complete facial paralysis occurs if intact neurons are reduced to less than 32% of the control value.
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Affiliation(s)
- S Kobayashi
- Department of Anatomy, Shinshu University School of Medicine, 3-1-1 Asahi, Nagano 390-8621, Matsumoto, Japan
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