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Kawamura K, Sasaki K, Sasaki SI, Tomita K. Axonal projection of the medullary expiratory neurons in the feline thoracic spinal cord. Respir Physiol Neurobiol 2024; 322:104218. [PMID: 38237882 DOI: 10.1016/j.resp.2024.104218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 01/12/2024] [Accepted: 01/13/2024] [Indexed: 01/26/2024]
Abstract
Expiratory neurons in the caudal ventral respiratory group extend descending axons to the lumbar and sacral spinal cord, and they possess axon collaterals, the distribution of which has been well-documented. Likewise, these expiratory neurons extend axons to the thoracic spinal cord and innervate thoracic expiratory motoneurons. These axons also give rise to collaterals, and their distribution may influence the strength of synaptic connectivity between the axons and the thoracic expiratory motoneurons. We investigated the distribution of axon collaterals in the thoracic spinal cord using a microstimulation technique. This study was performed on cats; one cat was used to make an anatomical atlas and six were used in the experiment. Extracellular spikes of expiratory neurons were recorded in artificially ventilated cats. The thoracic spinal gray matter was microstimulated from dorsal to ventral sites at 100-μm intervals using a glass-insulated tungsten microelectrode with a current of 150-250 μA. The stimulation tracks were made at 1 mm intervals along the spinal cord in segments Th9 to Th13, and the effective stimulating sites of antidromic activation in axon collaterals were systematically mapped. The effective stimulating sites in the contralateral thoracic spinal cord with expiratory neurons in the caudal ventral respiratory group (cVRG) occupied 14.4% of the total length of the thoracic spinal cord examined. The mean percentage of effective stimulating tracks per unit was 18.6 ± 4.4%. The distribution of axon collaterals of expiratory neurons in the feline thoracic spinal cord indeed resembled that reported in the upper lumbar spinal cord. We propose that a single medullary expiratory neuron exerts excitatory effects across multiple segments of the thoracic spinal cord via its collaterals.
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Affiliation(s)
- Kenta Kawamura
- Department of Physical Therapy, Ibaraki Prefectural University of Health Sciences, 4669-2 Ami, Ami-machi, Inashiki-gun, Ibaraki 300-0394, Japan.
| | - Kazumasa Sasaki
- Department of Anatomy, Toho University, 5-21-16 Ohmorinishi, Ohta-ku, Tokyo 143-8540, Japan
| | - Sei-Ichi Sasaki
- Toyo Public Health College, 6-21-7 Honmachi, Shibuya-ku, Tokyo 151-0071, Japan
| | - Kazuhide Tomita
- Department of Physical Therapy, Ibaraki Prefectural University of Health Sciences, 4669-2 Ami, Ami-machi, Inashiki-gun, Ibaraki 300-0394, Japan
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Sasaki K, Sasaki SI, Sato F. Corrigendum to 'Morphological analysis of neck muscle nerves and neurons in cats' [Tissue and Cell 82 (2023) 1-11/102077]. Tissue Cell 2024; 87:102301. [PMID: 38220546 DOI: 10.1016/j.tice.2024.102301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2024]
Affiliation(s)
- Kazumasa Sasaki
- Department of Anatomy, Toho University Graduate School of Medicine, Tokyo, Japan.
| | - Sei-Ichi Sasaki
- Center for Medical Sciences, Ibaraki Prefectural University of Health Sciences, Ibaraki, Japan
| | - Fumi Sato
- Department of Anatomy, Toho University, School of Medicine, Tokyo, Japan
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Sasaki K, Sasaki SI, Sato F. Corrigendum to "Morphological analysis of neck muscle nerves and neurons in cats" [Tissue Cell 82 (2023) 1-11 102077]. Tissue Cell 2023; 85:102237. [PMID: 37845107 DOI: 10.1016/j.tice.2023.102237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2023]
Affiliation(s)
- Kazumasa Sasaki
- Department of Anatomy, Toho University Graduate School of Medicine, Tokyo, Japan.
| | - Sei-Ichi Sasaki
- Center for Medical Sciences, Ibaraki Prefectural University of Health Sciences, Ibaraki, Japan
| | - Fumi Sato
- Department of Anatomy, Toho University, School of Medicine, Tokyo, Japan
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Sasaki K, Sasaki SI, Sato F. Morphological analysis of neck muscle nerves and neurons in cats. Tissue Cell 2023; 82:102077. [PMID: 37018926 DOI: 10.1016/j.tice.2023.102077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 03/18/2023] [Accepted: 03/19/2023] [Indexed: 03/28/2023]
Abstract
Previous studies have failed to show morphological differences between neck muscle alpha and gamma motor fibers or alpha and gamma motoneurons. The present study aimed to investigate the morphological features of neck muscle motor nerves and motoneurons in cats. To determine the morphological features of peripheral motor fibers, the value of the outer contours of each fiber was converted into a perfect circle after ganglionectomy to remove sensory fibers, and the fiber diameters were calculated based on their circumferences. The sizes of neck motor fibers in the peripheral nerves had an evident bimodal distribution into small and large fiber groups, as depicted in histograms. The sizes of small and large motor fibers ranged from 2 to 12 µm and from 12 to 40 µm, respectively. The small fiber group is likely to correspond to gamma motor fibers and the large fiber group to alpha motor fibers. The morphological features of neck muscle motoneurons sectioned in the horizontal plane were examined using the horseradish peroxidase (HRP) retrograde labeling technique. The diameters of the biventer cervicis and complexus motoneurons had bimodal distributions. The inflection point between the small and large diameter population was 28 µm for the biventer cervicis and 26 µm for the complexus. We also observed that larger neurons displayed more dendrites. In conclusion, we could identify morphological differences likely to correlate with alpha and gamma motoneurons in both neck muscle peripheral nerves and neck motoneurons.
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Affiliation(s)
- Kazumasa Sasaki
- Department of Anatomy, Toho University, School of Medicine, Tokyo, Japan.
| | - Sei-Ichi Sasaki
- Center for Medical Sciences, Ibaraki Prefectural University of Health Sciences, Ibaraki, Japan
| | - Fumi Sato
- Department of Anatomy, Toho University, School of Medicine, Tokyo, Japan
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Muramatsu K, Niwa M, Sasaki SI. Properties of Renshaw-like cells excited by recurrent collaterals of pudendal motoneurons in the cat. J Physiol Sci 2020; 70:37. [PMID: 32660421 PMCID: PMC10717121 DOI: 10.1186/s12576-020-00763-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Accepted: 07/06/2020] [Indexed: 11/10/2022]
Abstract
Although anatomical studies have indicated pudendal motoneurons to give off recurrent collaterals, they are not considered to make synapses onto interneurons, such as Renshaw cells, and rather terminate their own signals. No study till date has examined interneurons being driven by recurrent collaterals of pudendal motoneurons. Here, we aimed to investigate the existence of Renshaw cells driven by pudendal motoneurons along with the recurrent inhibition of the latter. Extracellular recordings were obtained from the ventral horn of the sacral spinal cord of anesthetized cats. Dorsal roots were sectioned, and motor axons were electrically stimulated. Renshaw-like cells driven by recurrent collaterals, with high-frequency firings at short latency discharge, were observed around Onuf's nucleus. However, the recurrent inhibitory post-synaptic potentials were not recorded by intracellular recordings from the pudendal motoneurons. In summary, we found Renshaw-like cells driven by pudendal motoneurons, but we could not identify the synaptic connection of these neurons.
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Affiliation(s)
- Ken Muramatsu
- Department of Physical Therapy, Kyorin University, 5-4-1 Shimorenjaku, Mitaka, Tokyo, 181-8612, Japan.
| | - Masatoshi Niwa
- Department of Occupational Therapy, Kyorin University, 5-4-1 Shimorenjaku, Mitaka, Tokyo, 181-8612, Japan
| | - Sei-Ichi Sasaki
- Center for Medical Sciences, Ibaraki Prefectural University of Health Sciences, 4669-2 Ami, Ami-machi, Inashiki, Ibaraki, 300-0394, Japan
- Toyo Public Health College, 6-21-7 Hommachi, Shibuya-ku, Tokyo, 151-0071, Japan
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Sasaki SI, Muramatsu K, Niwa M. Firing properties of medullary expiratory neurons during fictive straining in cats. J Physiol Sci 2019; 69:961-968. [PMID: 31571147 PMCID: PMC10717739 DOI: 10.1007/s12576-019-00715-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 09/17/2019] [Indexed: 10/25/2022]
Abstract
Expiratory (E) neurons in the caudal nucleus retroambigualis extend descending spinal axons to the lumbar and sacral spinal cord. Discharge rates of single E neurons were recorded to examine differences in activity of E neurons projecting to the lumbar or sacral spinal cord during fictive straining induced by distention of the colon with a balloon. Firing frequencies of E neurons with descending axons in the thoracic and lumbar spinal cord increased during the repetitive rise of rectum pressure, whereas those of E neurons with descending axons in the sacral spinal cord decreased. E neurons with descending axons in the thoracic/lumbar and sacral spinal cord exhibit different firing characteristics during the repetitive rise of rectum pressure when straining during defecation. The activity of abdominal nerves during fictive straining is in phase with changes in rectum pressure, but out of phase with the activity of E neurons.
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Affiliation(s)
- Sei-Ichi Sasaki
- Center for Medical Sciences, Ibaraki Prefectural University of Health Sciences, Ibaraki, Japan
- Toyo Public Health College, 6-21-7 Hommachi, Shibuya-ku, Tokyo, 151-0071, Japan
| | - Ken Muramatsu
- Department of Physical Therapy, Kyorin University, Tokyo, Japan
| | - Masatoshi Niwa
- Department of Occupational Therapy, Kyorin University, 5-4-1 Shimorenjaku, Mitaka, Tokyo, 181-8612, Japan.
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Niwa M, Muramatsu K, Nakayama K, Sasaki SI. Electrophysiological properties of Ia excitation and recurrent inhibition in cat abdominal motoneurons. J Physiol Sci 2019; 69:253-262. [PMID: 30324557 PMCID: PMC10716931 DOI: 10.1007/s12576-018-0643-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 09/28/2018] [Indexed: 11/29/2022]
Abstract
Ia excitation and recurrent inhibition are basic neuronal circuits in motor control in hind limb. Renshaw cells receive synaptic inputs from axon collaterals of motoneurons and inhibit motoneurons and Ia inhibitory interneurons. It is important to know properties of Ia excitation and recurrent inhibition of trunk muscle such as abdominal muscles. The abdominal muscles have many roles and change those roles for different kind of functions. Intracellular recordings were obtained from the abdominal motoneurons of the upper lumbar segments in cats anesthetized. First, dorsal roots were left intact, and sensory and motor axons were electrically stimulated. Ia excitatory post-synaptic potentials were elicited in five of eight motoneurons at same segment stimulated. Second, dorsal roots were sectioned, and motor axons were electrically stimulated. Recurrent inhibitory post-synaptic potentials were elicited in one of 11 abdominal motoneurons. Renshaw cells extracellularly fired high-frequency bursts at short latency and at same segment stimulated.
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Affiliation(s)
- Masatoshi Niwa
- Department of Occupational Therapy, Kyorin University, 5-4-1 Shimorenjaku, Mitaka, Tokyo, 181-8612, Japan.
| | - Ken Muramatsu
- Department of Physical Therapy, Health Science University, 7187 Kodachi, Fujikawaguchiko, Yamanashi, 401-0380, Japan
| | - Kiyomi Nakayama
- Department of Oral Physiology, School of Dentistry, Showa University, 1-5-8 Hatanodai, Shinagawa, Tokyo, 142-8555, Japan
| | - Sei-Ichi Sasaki
- Center for Medical Sciences, Ibaraki Prefectural University of Health Sciences, 4669-2 Ami, Ami-machi, Inashiki, Ibaraki, 300-0394, Japan
- Tokyo Public Health College, 6-21-7 Hommachi, Shibuya-ku, Tokyo, 151-0071, Japan
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Muramatsu K, Niwa M, Tamaki T, Ikutomo M, Masu Y, Hasegawa T, Shimo S, Sasaki SI. Effect of streptozotocin-induced diabetes on motoneurons and muscle spindles in rats. Neurosci Res 2016; 115:21-28. [PMID: 27826051 DOI: 10.1016/j.neures.2016.10.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 10/17/2016] [Accepted: 10/27/2016] [Indexed: 12/30/2022]
Abstract
This study examined the alterations in the number and size of motoneurons innervating the medial gastrocnemius (MG) and biceps femoris (BF) motor nuclei in diabetic rats (12 or 22 weeks after injection of streptozotocin) and age-matched controls using retrograde labeling technique. Additionally, morphological alterations of muscle spindles in BF and MG muscles were tested. Significantly fewer labeled MG motoneurons were found in 12- and 22-week diabetic rats as compared with age-matched control animals. In contrast, the number of BF motoneurons was preserved in each group. Compared to control animals, the ratio of larger motoneurons of MG and BF muscle were decreased at 12 weeks, and smaller MG motoneurons were drastically decreased at 22 weeks. Moreover, MG muscle spindle showed reduction of its number and increase of intrafusal muscle fibers; however, BF muscle spindles showed little or no difference from control animals. We conclude that there is an early loss of alpha motoneurons for both MG and BF muscles followed by a later loss of gamma motoneurons in MG muscle in diabetic animals. Moreover, loss of gamma motoneuron might induce atrophy of MG muscle spindles.
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Affiliation(s)
- Ken Muramatsu
- Department of Physical Therapy, Health Science University, Yamanashi, Japan.
| | - Masatoshi Niwa
- Department of Occupational Therapy, Kyorin University, Tokyo, Japan
| | - Toru Tamaki
- Department of Physical Therapy, Health Science University, Yamanashi, Japan
| | - Masako Ikutomo
- Department of Physical Therapy, Health Science University, Yamanashi, Japan
| | - Yujiro Masu
- Department of Physical Therapy, Health Science University, Yamanashi, Japan
| | - Tatsuya Hasegawa
- Division of Human Environmental Science, Mount Fuji Research Institute, Yamanashi, Japan
| | - Satoshi Shimo
- Department of Occupational Therapy, Health Science University, Yamanashi, Japan
| | - Sei-Ichi Sasaki
- Center for Medical Sciences, Ibaraki Prefectural University of Health Sciences, Ibaraki, Japan
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Niwa M, Muramatsu K, Sasaki SI. Discharge patterns of abdominal and pudendal nerves during induced defecation in anesthetized cats. J Physiol Sci 2015; 65:223-31. [PMID: 25682059 PMCID: PMC10717334 DOI: 10.1007/s12576-015-0362-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Accepted: 01/15/2015] [Indexed: 10/24/2022]
Abstract
Defecation is thought to be achieved not only by contraction of the colon, but also by a rise in intra-abdominal pressure. In this study we recorded the discharges of nerves innervating the abdominal (Abd) muscles, diaphragm, external anal sphincter (EAS) muscle and pelvic floor (PF) muscles during induced defecation evoked by distention of an expellable balloon to reveal defecation-related muscle activities. The discharges of the Abd muscle and phrenic (Phr) nerves increased when rectal pressure increased. The discharges of the EAS and PF nerves usually increased in proportion to the pressure in the rectum and maintained a constant activity level, although some trials showed inhibition. The results suggest that activities of these muscles increase the intra-abdominal pressure.
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Affiliation(s)
- Masatoshi Niwa
- Department of Occupational Therapy, Kyorin University, 476 Miyashita, Hatioji, Tokyo, 192-8508, Japan,
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Muramatsu K, Niwa M, Nagai M, Kamimura T, Sasaki SI, Ishiguro T. The size of motoneurons of the gastrocnemius muscle in rats with diabetes. Neurosci Lett 2012; 531:109-13. [PMID: 23127853 DOI: 10.1016/j.neulet.2012.10.031] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Revised: 10/07/2012] [Accepted: 10/19/2012] [Indexed: 11/15/2022]
Abstract
Alterations in the number and size of motoneurons were studied in the medial gastrocnemius (MG) motor nucleus of diabetic rats (12 or 22 weeks after injection of storeptozotocin) and age-matched controls. Each group contained 6 animals. MG motoneurons were retrogradely labeled by dextran-fluorescein and the number and size of cell bodies were examined. Significantly fewer labeled MG motoneurons were found in the 22-week diabetic rats as compared with age-matched control animals. The mean soma diameter of MG motoneurons was significantly smaller in the 12- and 22-week diabetic animals. Furthermore the soma size for 22-week diabetic animals was smaller than for 12-week diabetic animals. The distribution of average soma diameters in the MG nucleus of control animals was bimodal; cells with larger average diameter were presumed to be alpha-motoneurons and those with smaller diameters were presumed to be gamma. Compared to control animals, the number of smaller MG motoneurons was reduced in 12 week diabetic animals. By 22 weeks, diabetic animals had no small MG motoneurons and the size distribution became unimodal. We conclude that there is a significant decrease in the absolute number and size of MG motoneurons in diabetic rats, with the possibility that the decrease occurred predominantly among the smaller gamma-motoneurons.
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Affiliation(s)
- Ken Muramatsu
- Department of Physical Therapy, Health Science University, Yamanashi, Japan.
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Muramatsu K, Niwa M, Sasaki SI. Activity of the external anal sphincter muscle during defecation in the cat. Neurosci Res 2011. [DOI: 10.1016/j.neures.2011.07.698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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12
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Horaguchi T, Yamakawa Y, Sasaki SI. Finger counting habit influences on the performance in the temporal order judgment task. Neurosci Res 2011. [DOI: 10.1016/j.neures.2011.07.770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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Uga M, Niwa M, Ochiai N, Sasaki SI. Activity patterns of the diaphragm during voluntary movements in awake cats. J Physiol Sci 2010; 60:173-80. [PMID: 20087707 PMCID: PMC10717415 DOI: 10.1007/s12576-009-0081-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2009] [Accepted: 12/09/2009] [Indexed: 10/19/2022]
Abstract
The diaphragm is an important inspiratory muscle, and is also known to participate in the postural function. However, the activity of the diaphragm during voluntary movements has not been fully investigated in awake animals. In order to investigate the diaphragmatic activity during voluntary movements such as extending or rotating their body, we analyzed the electromyogram (EMG) of the diaphragm and trunk muscles in the cat using a technique for simultaneous recordings of EMG signals and video images. Periodic respiratory discharges occurred in the left and right costal diaphragm when the cat kept still. However, once the cat moved, their periodicity and/or synchrony were sometimes buried by non-respiratory activity. Such non-periodic diaphragmatic activities during voluntary movements are considered as the combination of respiratory activity and non-respiratory activity. Most of the diaphragmatic activities started shortly after the initiation of standing-up movements and occurred after the onset of trunk muscle activities. Those activities were more active compared to the normal respiratory activity. During rotation movements, left and right diaphragmatic activities showed asymmetrical discharge patterns and higher discharges than those during the resting situation. This asymmetrical activity may be caused by taking different lengths of each side of the diaphragm and trunk muscles. During reaching movements, the diaphragmatic activity occurred prior to or with the onset of trunk muscle activities. It is likely that diaphragmatic activities during reaching movements and standing-up movements may have been controlled by some different control mechanisms of the central nervous system. This study will suggest that the diaphragmatic activity is regulated not only by the respiratory center but also by inputs from the center for voluntary movements and/or sensory reflex pathways under the awake condition.
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Affiliation(s)
- Minako Uga
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki, Japan.
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Horaguchi T, Yamakawa Y, Sasaki SI. Different type of stimulation reminds different type of mental number line. Neurosci Res 2010. [DOI: 10.1016/j.neures.2010.07.1326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Uga M, Niwa M, Ochiai N, Sasaki SI. The Diaphragmatic Activities During Trunk Movements. Advances in Experimental Medicine and Biology 2010; 669:253-6. [DOI: 10.1007/978-1-4419-5692-7_51] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Muramatsu K, Niwa M, Sato K, Sasaki SI. Properties of Renshaw cells excited by recurrent collaterals of pudendal motoneurons in the cat. Neurosci Res 2009. [DOI: 10.1016/j.neures.2009.09.869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Muramatsu K, Sasaki SI, Cho Y, Sato K. Morphological analysis of the external anal sphincter motor nerve and its motoneurons in the cat. Anat Sci Int 2008; 83:247-55. [DOI: 10.1111/j.1447-073x.2008.00238.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Sasaki S, Oguni E, Sasaki SI. Caudal expiratory neuron in the monkey brainstem. Auton Neurosci 2007. [DOI: 10.1016/j.autneu.2007.06.243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Muramatsu K, Cho Y, Sato K, Sasaki SI. Morphological study of external anal sphincter motoneurons and motor nerve fibers. Auton Neurosci 2007. [DOI: 10.1016/j.autneu.2007.06.190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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21
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Uga M, Niwa M, Ochiai N, Sasaki SI. Activity patterns of diaphragm during voluntary movements in awake cats. Neurosci Res 2007. [DOI: 10.1016/j.neures.2007.06.1455] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Sakuta N, Sasaki SI, Ochiai N. Analysis of activity of motor units in the biceps brachii muscle after intercostal-musculocutaneous nerve transfer. Neurosci Res 2005; 51:359-69. [PMID: 15740799 DOI: 10.1016/j.neures.2004.12.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2004] [Accepted: 12/08/2004] [Indexed: 10/25/2022]
Abstract
We examined respiratory activity of motor units (MUs) in the internal intercostal nerves (IICNs)-transferred biceps brachii muscle (IC-biceps) in cats. MUs of IC-biceps showed respiratory discharges in inspiratory and expiratory phases, and these were enhanced by CO2 inhalation. Narrowing the airway also enhanced inspiratory and expiratory MUs activity. A mechanical load to the thorax immediately enhanced inspiratory MUs activity and weakened expiratory MUs activity. We analyzed the cross-correlation of MUs activity in interchondral muscle and IC-biceps to characterize the respiratory spinal descending inputs to motoneurons. We confirmed the short-term synchronization from interchondral muscles indicating divergence of a single respiratory presynaptic axon to thoracic motoneurons, but could not find synchronization from IC-biceps. The motor axonal conduction velocity (axonal CV) of IC-biceps MUs was lower than that of interchondral muscles. There was no correlation between the respiratory recruitment order of IC-biceps MUs and their axonal CV. These results indicate that IC-biceps shows the respiratory activities and afferent inputs from intercostal muscle spindles in the neighboring segments remain influential on activity of IC-biceps. In addition, the short-term synchronization from IC-biceps could not be found, suggesting that the intercostal nerve transfer alters the respiratory spinal descending inputs to thoracic motoneurons.
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Affiliation(s)
- Naoki Sakuta
- Department of Orthopaedic Surgery, Institute of Clinical Medicine, University of Tsukuba, 1-1-1 Tennodai, Ibaraki 305-8577, Japan.
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Nakayama K, Niwa M, Sasaki SI, Ichikawa T, Hirai N. Morphology of single primary spindle afferents of the intercostal muscles in the cat. J Comp Neurol 1998; 398:459-72. [PMID: 9717703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
A reconstruction was made of the trajectory of primary spindle afferents from the intercostal muscles in the spinal cord of the cat. Intraaxonal recordings were performed from the primary spindle afferents that were identified by their response to lung inflation and stimulus threshold to activate the action potentials. The afferents were stained by using intraaxonal injection of horseradish peroxidase (HRP). Results were obtained mainly from internal intercostal Ia fibers, which entered the spinal cord and bifurcated into ascending and descending branches. The ascending branches could be traced up to 10.7 mm, and the descending branches could be traced up to 7.3 mm. The ascending branches extended to the next segment. Collaterals ranging from one to six were given off from these branches. The distances between adjacent collaterals ranged from 0.9 mm to 4.7 mm. Each collateral had similar morphological characteristics. The collaterals entered the dorsal horn and ran toward lamina IX through the medial half of the gray matter. Fine branches and boutons were given off in laminae V, VII, VIII, and IX. The aggregations of these branches were found in lamina VII, mainly in the region of Clarke's column and in the ventral and ventrolateral regions thereof and in lamina IX, mainly in the nucleus lateromedialis. Most terminals did not contact the somata of target neurons in all laminae in which terminals were found. However, a few terminals were found to contact large neurons in lamina IX. In addition to these aggregates, there were some terminals scattered throughout the ventral horn. Thus, it was concluded that single intercostal Ia afferents project to the region of Clarke's column, to the intercostal motor nucleus, and to the intermediate regions.
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Affiliation(s)
- K Nakayama
- Center for Medical Sciences, Ibaraki Prefectural University of Health Sciences, Japan
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Niwa M, Nakayama K, Uchino H, Sasaki SI. 1546 Morphological study of external oblique motor nerve and nucleus in the cat. Neurosci Res 1997. [DOI: 10.1016/s0168-0102(97)90534-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Kimura T, Miyashita Y, Funatsu K, Sasaki SI. Quantitative structure--activity relationships of the synthetic substrates for elastase enzyme using nonlinear partial least squares regression. J Chem Inf Comput Sci 1996; 36:185-9. [PMID: 8882809 DOI: 10.1021/ci9501103] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Eighty-nine synthetic substrates for elastase enzyme and its activities (log 1/Km, log kcat, and log Kcat/Km) are treated using partial least squares (PLS) and quadratic partial least squares (QPLS). Chemical features of synthetic substrates are described using principal properties (PPs). By using the QPLS method, we obtain the nonlinear model equations for three properties (log 1/Km, log kcat, and log kcat/km) with the correlation coefficient 0.736, 0.918, and 0.868, respectively. Also, the predictive correlation coefficients for these model equations are 0.640, 0.865, and 0.793, respectively. By this study, it becomes clear that the z2 value of the amino acid residue on position A and the size of the side chain for amino acid residues on position B are related to the properties of the synthetic substrates.
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Affiliation(s)
- T Kimura
- Department of Knowledge-Based Information Engineering, Toyohashi University of Technology, Japan
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Sasaki SI, Uchino H. Axon branching of medullary expiratory neurons in the sacral spinal cord of the cat. Adv Exp Med Biol 1995; 393:63-6. [PMID: 8629520 DOI: 10.1007/978-1-4615-1933-1_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- S I Sasaki
- Department of Physiology, Tokyo Medical College, Japan
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Abstract
Intraspinal axon collaterals of expiratory (E) neurons in the caudal nucleus retroambigualis extending their desending spinal axons to the lower lumbar (L6-L7) and the sacral (S1-S3) segments were investigated in anesthetized cats. To search for axon collaterals of single E neurons in the lumbar segments, the spinal gray matter was microstimulated from the dorsal to the ventral sites at 100 microns intervals with an intensity of 150-250 microA at 1 mm intervals rostrocaudally along the spinal cord, and effective stimulating sites of antidromic activation in axon collaterals were systematically mapped. In addition, the detailed trajectory of collaterals in the upper lumbar (L1-L3), the middle lumbar (L4-L5), and the sacral (S1-S3) spinal cord was examined by microstimulation at a matrix of points 100-200 microns apart with a maximum stimulus intensity of 50 microA. The trajectory of axon collaterals was reconstructed on the basis of the location of low-threshold foci and the latency of antidromic spikes. Virtually all E neurons examined had 1-7 collaterals at widely separated segments of the lumbar cord. Many axon collaterals were found in the upper lumbar spinal cord as compared to the middle and the lower lumbar spinal cord. The locations of axon collaterals in the upper lumbar spinal cord overlapped with those of abdominal motoneurons. Axon collaterals in the sacral gray matter were found in 3 of 9 E neurons. Axon collaterals were found within the nucleus of Onuf, in the region dorsal to the nucleus of Onuf, and in the intermediate region. The functional significance of the divergent distribution of multiple axon collaterals of single E neurons in different spinal levels of the lumbar and the sacral spinal cord is discussed in relation to the respiratory function of E neurons and other spinal motor activities.
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Affiliation(s)
- S I Sasaki
- Department of Physiology, Tokyo Medical College, Japan
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Uchino Y, Sasaki SI, Imagawa M, Uchino H, Isu N, Sakuma A. Properties and axonal trajectories of inhibitory vestibulocollic neurons in the horizontal canal system of the cat. ACTA ACUST UNITED AC 1990. [DOI: 10.1016/0921-8696(90)90869-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Abstract
The feasibility of spindle afferent recording during naturally or electrically induced hindlimb movements is demonstrated in the case of spinalized, decapitated turtles. Since these recordings are obtained from fine filaments of exposed dorsal roots, it is possible for the experimenter to select the afferents of interest. This feasibility, together with the fact that spinally generated movements are readily exhibited, make the turtle an attractive animal for the study of spinal motor control mechanisms.
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Matsueda S, Karube A, Sasaki SI. [Studies on sesquiterpenelactones. X. Mass spectra of eudesmane-sesquiterpenelactones (author's transl)]. YAKUGAKU ZASSHI 1977; 97:1046-9. [PMID: 925874 DOI: 10.1248/yakushi1947.97.9_1046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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