著者

Alejandro Lucía Jesús Hoyos Javier Pardo José L. Chicharro

出版者

日本生理学会

雑誌

The Japanese Journal of Physiology (ISSN:0021521X)

巻号頁・発行日

vol.50, no.3, pp.381-388, 2000 (Released:2004-06-22)

参考文献数

32

被引用文献数

32 62

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The aim of this longitudinal study was to analyze the changes in several metabolic and neuromuscular variables in response to endurance training during three defined periods of a full sports season (rest, precompetition and competition). The study population was formed by thirteen professional cyclists (age ± SEM: 24 ± 1 years; mean V(dot)o2 max ~74 ml·kg−1·min−1). In each testing session, subjects performed a ramp test until exhaustion on a cycle ergometer (workload increases of 25 W·min−1). The following variables were recorded every 100 W until the tests: oxygen consumption (V˙O2 in l·min−1), respiratory exchange ratio (RER in V(dot)co2·V˙O2−1) and blood lactate, pH and bicarbonate concentration [HCO3−]. Surface electromyography (EMG) recordings were also obtained from the vastus lateralis to determine the variables: root mean square voltage (rms-EMG) and mean power frequency (MPF). RER and lactate values both showed a decrease (p < 0.05) throughout the season at exercise intensities corresponding to submaximal workloads. In contrast, no significant differences were found in mean pH or [HCO3−]. Finally, rms-EMG tended to increase during the season, with significant differences (p < 0.05) observed mainly between the competition and rest periods at most workloads. In contrast, precompetition MPF values increased (p < 0.05) with respect to resting values at most submaximal workloads but fell (p < 0.05) during the competition period. Our findings suggest that endurance conditioning induces the following general adaptations in elite athletes: (1) lower circulating lactate and increased reliance on aerobic metabolism at a given submaximal intensity, and possibly (2) an enhanced recruitment of motor units in active muscles, as suggested by rms-EMG data.

著者

ラーマン ムスタフィジュー 山村 健介 井上 誠 黒瀬 雅之 山田 好秋

出版者

日本生理学会

雑誌

日本生理学会大会発表要旨集

巻号頁・発行日

vol.2005, pp.S172, 2005

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Previous studies have shown that the jaw-opening reflex (JOR) is modulated during mastication. However in these studies, analyses have been carried out for limited period within the masticatory sequence (i.e. from food intake to just before swallow). Our aim is to study if the modulatory pattern of the JOR is consistent throughout the masticatory sequence in awake rabbits. The masticatory sequence was divided into three masticatory periods (preparatory, rhythmic-chewing and preswallow periods) based on the jaw movement patterns and the activity pattern of the jaw muscles. Electromyographic activity of the jaw-opening muscle (Digastric) and the jaw movement trajectories were recorded. Repetitive electrical stimulation (single pulse, 0.2 ms duration at a rate of 1 Hz, 1.2 times the threshold) of the inferior alveolar nerve was conducted before (for control response) and during mastication to evoke the JOR. The amplitude of the JOR was normalized to the control response and the modulatory pattern of the JOR was compared among the masticatory periods. The JOR was generally suppressed during the rhythmic-chewing and the preswallow periods; the suppressive effect was phasically weakened in the middle part of the jaw opening during the rhythmic-chewing period. On the other hand, the reflex was not only suppressed but also facilitated during the preparatory period. The results suggest that the modulatory pattern of the jaw-opening reflex is different among the masticatory periods. <b>[Jpn J Physiol 55 Suppl:S172 (2005)]</b>

著者

余 錦 佐藤 純 舟久保 恵美 小畑 光央 水村 和枝

出版者

日本生理学会

雑誌

日本生理学会大会発表要旨集

巻号頁・発行日

vol.2004, pp.S245, 2004

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To examine the effects of change in meteorological factors on autonomic parameters in conscious animals, male Sprague-Dawley rats (n = 11) were exposed to lowering barometric pressure (LP) in a climate-controlled room. Systemic blood pressure (BP) was telemetrically recorded using a radio-transmitter equipped with a BP transducer. Heart rate (HR) was calculated from BP data and pulse interval variability was analyzed by power spectrograms obtained by the fast-Fourier transform algorithm. The low-frequency (LF: 0.02-0.6 Hz) power, high-frequency (HF: 0.8-3.0 Hz) power and LF/HF ratio, an index of relative sympathetic activity, were calculated. The rats were exposed to LP by decreasing the barometric pressure of the room by 27 hPa lower than the atmospheric pressure. This was done over 8 min. The pressure was maintained at this level for 29 min, and then returned to the baseline pressure over 8 min. The BP markedly increased after reaching the pre-set low pressure and reached the peak value at the middle of LP-exposure period. The HR and LF/HF ratio clearly rose in the early part of the LP-exposure period and then gradually decreased to the level before exposure. The LF/HF ratio also transiently increased at the recompression period. These results show that lowering barometric pressure within the range of natural environmental fluctuation induces autonomic responses in conscious rats. The increase in the LF/HF ratio during LP exposure indicates that low pressure environment induces sympathetic > parasympathetic activation. <b>[Jpn J Physiol 54 Suppl:S245 (2004)]</b>

著者

Yudai Takarada Tomomi Tsuruta Naokata Ishii

出版者

日本生理学会

雑誌

The Japanese Journal of Physiology (ISSN:0021521X)

巻号頁・発行日

vol.54, no.6, pp.585-592, 2004 (Released:2005-03-12)

参考文献数

36

被引用文献数

56 120

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To obtain insight into the relative contributions of exercise and occlusive stimuli to these muscular adaptations, the present study investigated the short- and long-term effects of varied combinations of low- intensity exercise and vascular occlusion. The subjects were separated into 3 groups (n = 6 for each group): low- intensity with vascular occlusion (LIO), low-intensity without vascular occlusion (LI), and vascular occlusion without exercise (VO). LIO and LI groups performed bilateral knee extension exercises in seated positions with an isotonic extension machine. In the LIO group, both sides of the thigh were pressure-occluded at the proximal end by means of a tourniquet during the entire session of exercise (˜10 min), whereas only the occlusion with the same pressure and duration was given in the VO group. The mean occlusion pressure was 218 ± 8.1 mmHg (mean ± SE). The exercise session consisted of five sets of exercise at an intensity of 10-20% 1RM and was performed twice a week for 8 wk. After the period of exercise training, isometric and isokinetic strengths at all velocities examined increased significantly in the LIO group (p < 0.05), whereas no significant change in strength was seen in the LI and VO groups. The increase in muscular strength in LIO was associated with a significant increase in the cross-sectional area of knee extensor muscles by 10.3 ± 1.6%. The plasma growth hormone concentration measured 15 min after the session of exercise showed a marked increase only in LIO. The results showed that the low-intensity exercise and occlusive stimuli have cooperative effects in the long-term adaptation of muscle and an acute response to growth hormone.

著者

白 云哲 奥村 敏 常松 尚志 焦 其彬 小野 伸二 鈴木 さやか 黒谷 玲子 佐藤 元彦 南沢 享 石川 義弘

出版者

日本生理学会

雑誌

日本生理学会大会発表要旨集

巻号頁・発行日

vol.2008, pp.180-180, 2008

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Objective: Autonomic nervous activity is altered under microgravity. Cardiac response to autonomic regulation is mostly determined by &beta;-adrenergic receptors/cAMP signal that is regulated by adenylyl cyclase (AC). We thus examined the role of a major cardiac AC isoform, type 5 AC (AC5), in the autonomic regulation of the heart under microgravity induced by parabolic flights. Methods: We used transgenic mice with either disrupted (AC5KO) or overexpressed AC5 in the heart (AC5TG), and analyzed heart rate variability during parabolic flight. Results: The standard deviation of normal R-R intervals, a marker of total autonomic variability, was significantly greater under microgravity in AC5KO while no significant changes in WT and AC5TG. LF (low frequency)/HF (high frequency), a marker of sympathetic activity, became significantly lower under microgravity in WT and AC5TG while there was no such a decrease in AC5KO. Normalized HF, a marker of parasympathetic activity, became significantly greater in WT under microgravity, and became even greater in AC5TG, while no such increase in AC5KO. Conclusions: Putting together, changes in autonomic indexes in response to microgravity were augmented in AC5TG while attenuated in AC5KO, suggesting that AC5 plays a major role in determining the magnitude of cardiac responses to autonomic regulation under microgravity. <b>[J Physiol Sci. 2008;58 Suppl:S180]</b>

著者

金子 章道

出版者

日本生理学会

雑誌

日本生理学雜誌 (ISSN:00319341)

巻号頁・発行日

vol.63, no.4, pp.81-83, 2001-04-01

著者

グロス コーネリアス

出版者

日本生理学会

雑誌

日本生理学会大会発表要旨集

巻号頁・発行日

vol.2008, pp.2, 2008

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People who suffer from anxiety tend to interpret ambiguous situations, situations that could potentially be dangerous but not necessarily so, as threatening. It is also recognized that a person's propensity for anxiety can be influenced by early life experiences. We have shown that signaling by the neurotransmitter serotonin during early postnatal development in the mouse is about to moderate life-long anxiety behavior. Specifically, genetic or pharmacological blockade of the serotonin 1A receptor (Htr1aKO) during this period leads to increased anxiety both to innate anxiety cues (exposure novel arena) as well as enhanced fear conditioning to ambiguous, but not non-ambiguous conditioned stimuli. To examine the involvement of specific forebrain circuits in this phenotype, we developed a pharmacogenetic technique for the rapid tissue and cell-type specific silencing of neural activity in vivo. Inhibition of neurons in the central nucleus of the amygdala suppressed conditioned responses to both ambiguous and non-ambiguous cues. In contrast, inhibition of hippocampal dentate gyrus granule cells selectively suppressed conditioned responses to ambiguous cues and reversed the Htr1aKO phenotype. These data demonstrate that Htr1aKO mice have a bias in the processing of threatening cues that is moderated by hippocampal mossy fiber circuits and suggest that the hippocampus plays an important role in the response to ambiguous aversive stimuli. <b>[J Physiol Sci. 2008;58 Suppl:S2]</b>

著者

シュウ ワッシ

出版者

日本生理学会

雑誌

日本生理学会大会発表要旨集

巻号頁・発行日

vol.2006, pp.35, 2006

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Alzheimer's disease (AD), the most common form of senile dementia, is characterized by excessive production and accumulation of neurotoxic &beta;-amyloid (A&beta;) peptides which are proteolytically derived from &beta;-amyloid precursor protein (APP) via &beta;- and &gamma;-secretase cleavages. Experimental evidence from several groups including our own has demonstrated that the production of A&beta; occurs largely in the trans-Golgi network (TGN) where APP molecules predominantly reside. Mutations in presenilins genes are associated with the majority of familial AD likely through a mechanism of increase A&beta;42 production. Presenilins (PS, PS1 and PS2) along with their associated proteins including nicastrin (Nct), PEN2 and APH1 are essential for the &gamma;-secretase activity. The precise functions of Nct, APH-1 and PEN-2 have not been fully elucidated. Recent studies including ours suggest that PEN-2 mediates endoproteolysis of PS1, while APH-1 and Nct play regulatory roles in maintaining the stability of PS1 and the complex. PS1 knockout mice exhibit pre-neonatal lethality and PS1 has also been shown to affect numerous physiological functions including calcium homeostasis, skeletal development, neurite outgrowth, apoptosis, synaptic plasticity, tumorigenesis. These data strongly indicate critical physiological roles of PS1 addition to its essential role in &gamma;-secretase activity. We and others have reported that PS1 plays an important role in intracellular trafficking (especially from the TGN to the plasma membrane) of select membrane proteins including APP, PEN2 and nicastrin. The detailed cell biological mechanism for PS-mediated protein trafficking will be discussed. <b>[J Physiol Sci. 2006;56 Suppl:S35]</b>

著者

田原 優 平尾 彰子 坪井 琢磨 田中 麻貴 吉田 晶子 柴田 重信

出版者

日本生理学会

雑誌

日本生理学会大会発表要旨集

巻号頁・発行日

vol.2008, pp.90, 2008

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Glycine is now used as a chemical for promotion of sleep in humans. It has been demonstrated that glycine administration up to 2g/kg causes the increase of NREM sleep in sleep disturbed rat and hypothermia (0.6 C decrease) in rat. The administration of benzodiazepine not only caused the sleep but affected the circadian rhythm; it blocked the light-induced phase advance of activity rhythm and elevation of Per1 gene expression in the suprachiasmatic nucleus (SCN) in hamsters. In the present experiment, we examined the possibility whether glycine affect light-induced phase shift and c-fos expression in the SCN and retina of mice. Glycine dose-dependently decreased the body temperature of mice (1C decrease with 2 g/kg). After extended light exposure for 2 hrs in the night under LD cycle mouse was kept under constant dark condition. Glycine (0.5-2 g/kg) pretreatment before light exposure dose-dependently attenuated light-induced phase delay. Glycine (2g/kg) pretreatment slightly attenuated light-induced increase of Fos immunoreactivity in the mouse SCN. Further experiment should elucidate whether glycine administration itself causes the phase shift or not. The present results suggest that high dose of glycine may attenuate the light-induced phase shift of circadian clock. <b>[J Physiol Sci. 2008;58 Suppl:S90]</b>

著者

平尾 彰子 田原 優 井筒 裕之 本間 さと 本間 研一 柴田 重信

出版者

日本生理学会

雑誌

日本生理学会大会発表要旨集

巻号頁・発行日

vol.2008, pp.198, 2008

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Daily restricted feeding (RF) with fixed time during daytime causes an advance of circadian rhythm of mouse liver clock gene expression. However, the mechanism of entrainment signal is poorly understood. Here, we examine whether daily administration of various type of nutrition caused entrainment of liver clock gene expression rhythm using Bmal1-luciferase transgenic mouse. Circadian rhythm change of liver bioluminescence was recorded through Lumicycle after 1-6 days of administration of various nutrients. We administered the corn carbon dehydrate, egg albumin or soybean oil after adjustment of each calorie. Among these nutrients soybean oil has most strong effect on phase-shift of gene expression rhythm. Administration of glucose through oral or intraperitoneal caused the phase advance, however the value of change was small. Thus, slow supply of calorie may be important to cause phase shift. We still examine the other nutrients such as amino acids, dextrin and sugar. We also try to find the effect of combination of nutrients on phase-shift of liver clock. <b>[J Physiol Sci. 2008;58 Suppl:S198]</b>

著者

石井 久淑 新岡 丈治 和泉 博之

出版者

日本生理学会

雑誌

日本生理学会大会発表要旨集

巻号頁・発行日

vol.2006, pp.202-202, 2006

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The sympathetic nerve (SN) has been reported to be involved in the development of jaw muscle dysfunctions because the masseter muscle pain is usually accompanied with the increase in the SN activity. We have recently reported that there are parasympathetic (PS) vasodilator fibers in the rat masseter muscle and that these fibers would be involved in the regulation of the hemodynamics of jaw muscles (J. Physiol. 569, 617-629, 2005). It is still unclear whether there is an interaction between the PS vasodilatation (PSV) in the masseter muscle and the SN activity. The present study was thus designed to examine 1) the effect of SN activation on the PSV in the masseter muscle, and 2) the neural mechanisms mediating the effect in anesthetized rats. The PS mediated masseter muscle blood flow (MBF) increases were evoked by electrical stimulation of the central cut end of the lingual nerve. The magnitudes of MBF increase were significantly reduced by ongoing electrical stimulation of the superior cervical sympathetic trunk in a frequency-dependent manner (0.5-10 Hz). Pretreatment with BIBP 3226, a neuropeptide Y (NPY) Y1 receptor antagonist, significantly reduced 30-40% in this inhibition, but phentolamine had no effect. The present study indicates that the excessive SN activation inhibits the PSV in the masseter muscle, suggesting a potential role in the etiology of jaw muscle dysfunctions. This inhibitory action may be due to an interaction of the PS vsodilator fibers and NPY that would be released from sympathetic fibers. <b>[J Physiol Sci. 2006;56 Suppl:S202]</b>

著者

美藤 純弘 藤井 昭仁 舩橋 誠 小橋 基 松尾 龍二

出版者

日本生理学会

雑誌

日本生理学会大会発表要旨集

巻号頁・発行日

vol.2007, pp.236-236, 2007

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We showed the glutamatergic, GABAergic and glycinergic synaptic inputs to superior salivatory (SS) neurons which is the primary center of submandibular salivary secretion. This glutamatergic input is considered to derive from the forebrain and brainstem. In the present study, we studied how SS neurons receive the glutamatergic inputs from the forebrain and brainstem in rats. The SS neurons innervating the salivary glands were labeled by retrograde axonal transport of a fluorescent dye. Subsequently some rats were decerebrate. Whole-cell patch-clamp recordings were performed from the labeled cells in slices. Excitatory postsynaptic currents were evoked by electrical stimulation near the recording cell. As compared with normal SS neurons, decerebrate SS neurons showed 3 types of the responses: enhanced responses, similar responses, no responses. The SS neurons which showed enhanced EPSCs receive the excitatory inputs from forebrain and brainstem. Decerebration induced denervation-hypersensitivity in the glutamate receptors. Enhanced EPSCs may be evoked by stimulation of glutamatergic inputs from brainstem. The SS neurons displayed similar responses have mainly excitatory inputs from the brainstem. The SS neurons which displayed no responses produced larger currents by the application of glutamate, suggesting that this type has excitatory inputs exclusively from the forebrain. <b>[J Physiol Sci. 2007;57 Suppl:S236]</b>

著者

Yutaka Kano Kazumi Masuda Hirotaka Furukawa Mizuki Sudo Kazuyuki Mito Kazuyoshi Sakamoto

出版者

日本生理学会

雑誌

The Journal of Physiological Sciences (ISSN:18806546)

巻号頁・発行日

vol.58, no.5, pp.349-355, 2008 (Released:2008-10-29)

参考文献数

37

被引用文献数

8 20

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This study examined the effects of a different number of eccentric contractions (ECs) on histological characteristics, surface electromyogram (EMG) parameters (integral EMG, iEMG; muscle fiber conduction velocity, MFCV; and action potential waveform), and isometric peak torque using the rat EC model. Male Wistar rats (n = 40) were anesthetized, and ECs were initiated in the tibialis anterior muscle via electrical stimulation while the muscle was being stretched by electromotor. The rats were grouped according to the number of ECs (EC1, EC5, EC10, EC20, EC30, EC40, and EC100). Three days after the ECs, surface EMG signals and isometric peak torque were measured during evoked twitch contractions via electrical stimulation of the peroneal nerve. The muscle damage was evaluated from hematoxylin-eosin (HE) stained cross sections as a relative number of damaged fibers to intact fibers. Intense histological muscle damage (approximately 50% to 70% of the fiber), loss of isometric peak torque, disturbance of action potential waveform, and depression of iEMG (approximately −60% to −70%) were observed at EC20, EC30, EC40, and EC100. On the other hand, the MFCV did not change in any EC group. Although muscle damage and pathological surface EMG signals were not found at EC10, isometric peak torque was reduced significantly. In conclusion, the extent of histological muscle damage is not proportionally related to the number of ECs. Muscle damage was reflected by iEMG and action potential waveforms, but not by MFCV, which remained unaffected even though approximately 50% to 70% of the fiber demonstrated injury.

著者

Eisuke Ochi Koichi Nakazato Naokata Ishii

出版者

日本生理学会

雑誌

The Journal of Physiological Sciences (ISSN:18806546)

巻号頁・発行日

vol.57, no.1, pp.1-6, 2007 (Released:2007-02-24)

参考文献数

36

被引用文献数

15 26

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We investigated the effects of repeated eccentric exercise for rat medial gastrocnemius muscle on ankle joint stiffness and muscle connectin (titin) isoform composition (longer form, α-connectin; shorter form, β-connectin). Male Wistar rats were trained on a custom-made, isokinetic dynamometer (eccentric-exercise group, n = 6; sham-operated group, n = 6). The exercise session consisted of 20 eccentric contractions elicited by submaximal electric stimulations under anesthesia. The contracting muscle was forcibly lengthened by an isokinetic dorsi-flexion of the ankle joint (velocity, 30°/s; range of motion, 45°). Rats in the eccentric-exercise group were trained every two days for 20 days (10 sessions in total). The static passive resistive torque (PRT) of 45° at the ankle joint was used as a measure of the joint stiffness, and was determined before and after the experimental period. After 10 sessions of eccentric exercise, the wet weight of medial gastrocnemius muscle significantly increased (P < 0.05), whereas the static PRT significantly decreased (P < 0.05) in the eccentric-exercise group, when compared to the sham-operated group. Myosin-ATPase staining showed a decrease in the number of type IIb/IId fibers (P < 0.001) and an increase in the number of type IIa fibers (P < 0.05). However, no significant difference was seen in the connectin (titin) isoform composition between the eccentric-exercise group and the sham-operated group, suggesting that the reduction in PRT was not due to change in resting mechanical properties of muscle fibers.

著者

内野 善生 佐々木 成人 中陦 克己 板東 武彦 本郷 利憲 森 茂美 森 大志

出版者

日本生理学会

雑誌

日本生理学雜誌 (ISSN:00319341)

巻号頁・発行日

vol.63, no.10, pp.271-316, 2001-10-01

被引用文献数

2

著者

Nao Akiyama Yoshiki Ohnuki Yuki Kunioka Yasutake Saeki Takenori Yamada

出版者

日本生理学会

雑誌

The Journal of Physiological Sciences (ISSN:18806546)

巻号頁・発行日

vol.56, no.2, pp.145-151, 2006 (Released:2006-07-30)

参考文献数

28

被引用文献数

20 35

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The transverse stiffness of single myofibrils of skeletal and cardiac muscles was examined by atomic force microscopy. The microscopic images of both skeletal and cardiac myofibrils in a rigor state showed periodical striation patterns separated by Z-bands, which is characteristic of striated muscle fibers. However, sarcomere patterns were hardly distinguishable in the stiffness distributions of the relaxed myofibrils of skeletal and cardiac muscles. Myofibrils in a rigor state were significantly stiff compared with those in a relaxed state, and in each state, cardiac myofibrils were significantly stiffer compared with skeletal myofibrils. By proteolytic digestions of sarcomere components of myofibrils, it was suggested that cardiac myofibrils are laterally stiffer than skeletal myofibrils because Z-bands, connectin (titin) filament networks, and other components of sarcomere structures for the former myofibrils are stronger than those for the latter.

著者

Norio AKAIKE Nobutoshi HARATA

出版者

日本生理学会

雑誌

The Japanese Journal of Physiology (ISSN:0021521X)

巻号頁・発行日

vol.44, no.5, pp.433-473, 1994 (Released:2004-06-19)

被引用文献数

168 261

著者

Imran Ahmad QURESHI

出版者

日本生理学会

雑誌

The Japanese Journal of Physiology (ISSN:0021521X)

巻号頁・発行日

vol.45, no.4, pp.561-569, 1995 (Released:2004-06-19)

被引用文献数

15 38 53

著者

小河 繁彦 山崎 先也 岡本 啓 福田 俊 家森 幸男 田口 貞善

出版者

日本生理学会

雑誌

日本生理学雜誌 (ISSN:00319341)

巻号頁・発行日

vol.57, no.10, pp.419-426, 1995-10

被引用文献数

4

著者

Ichiji TASAKI

出版者

日本生理学会

雑誌

The Japanese Journal of Physiology (ISSN:0021521X)

巻号頁・発行日

vol.49, no.2, pp.125-138, 1999 (Released:2004-06-22)

被引用文献数

41 80