著者

福田 篤郎 秋山 節子

出版者

一般社団法人 日本生理学会

雑誌

The Japanese Journal of Physiology (ISSN:0021521X)

巻号頁・発行日

vol.13, no.5, pp.486-491, 1963

被引用文献数

3

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The resistance against endotoxin intoxication in endotoxin-tolerant rabbits was found to outlast far the ordinary “tolerance” in relation to the “macromolecular hematic syndrome” in which the clearing of endotoxin by the reticuloendothelial system might play a dominant role. The most characteristic in the tolerant state in relation to the resistance against the lethal effect of endotoxin was the lessening of the liver glycogen depletion after massive dose of endotoxin. That this might be due to the stability of liver metabolism was also suggested by the reduced metabolic response to thyroid in the tolerant state. The creatinuria induced by non-toxic dose of thyroid was found to be inhibited in the tolerant state.

著者

Tsuji Tsuyoshi Ohga Yoshimi Yoshikawa Yoshiro SAKATA Susumu KOHZUKI Hisaharu MISAWA Hiromi ABE Takehisa TABAYASHI Nobuoki KOBAYASHI Shuichi KITAMURA Soichiro TANIGUCHI Shigeki SUGA Hiroyuki TAKAKI Miyako

出版者

一般社団法人 日本生理学会

雑誌

The Japanese journal of physiology (ISSN:0021521X)

巻号頁・発行日

vol.49, no.6, pp.513-520, 1999-12-01

参考文献数

20

被引用文献数

7 23

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We have already reported the linear oxygen consumption per beat (Vo₂)&ndash;systolic pressure-volume area (PVA) relation from the curved left ventricular (LV) end-systolic pressure&ndash;volume relation (ESPVR) in the cross-circulated rat heart. The Vo₂ intercept (PVA-independent Vo₂) is primarily composed of Vo₂ for Ca²⁺ handling in excitation-contraction (E-C) coupling and basal metabolism. The aim of the present study was to obtain the oxygen cost of LV contractility that indicates Vo₂ for Ca²⁺ handling in E-C coupling per unit LV contractility change in the rat heart. Oxygen cost of LV contractility is obtainable as a slope of a linear relation between PVA-independent Vo₂ and LV contractility. We obtained a composite Vo₂&ndash;PVA relation line at a mid-range LV volume (mLVV) under gradually enhanced LV contractility by stepwise increased Ca²⁺ infusion and thus the gradually increased PVA-independent Vo₂ values. As a LV contractility index, we could not use E_max (ESP-V ratio; ESP/ESV) for the linear ESPVR because of the curved ESPVR in the rat LV. A PVA at a mLVV (PVA_mLVV) has been proposed as a good index for assessing rat LV mechanoenergetics. Since the experimentally obtained PVA_mLVV was not triangular due to the curved ESPVR, we propose an equivalent ESP-V ratio at a mLVV, (eESP/ESV)_mLVV, as a LV contractility index. This index was calculated as an ESP-V ratio of the specific virtual triangular PVA_mLVV that is energetically equivalent to the real PVA_mLVV. The present approach enabled us to obtain a linear relation between PVA-independent Vo₂ and (eESP/ESV)_mLVV and the oxygen cost of LV contractility as the slope of this relation.<br>

著者

Nomura Takeshi Kawano Fuminori Kang Myung Sun Lee Jun Hak Han Eun Young Kim Chang Keun Sato Yuzo Ohira Yoshinobu

出版者

一般社団法人 日本生理学会

雑誌

The Japanese Journal of Physiology (ISSN:0021521X)

巻号頁・発行日

vol.52, no.1, pp.85-93, 2002

被引用文献数

9

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The effects of 20-week cold exposure on contractile properties of soleus and extensor digitorum longus (EDL) muscles and plasma hormone levels were studied in rats. Twenty male Wistar rats (5 week old) were randomly divided into 2 groups (n = 10 each): cage-control and cold-exposed. The rats in the cold-exposed group were immersed in shoulder-deep water (~18&deg;C) for 1 h/d, 5 d/week, for 20 weeks. The temperature and humidity of the animal room with 12:12 h light-dark cycle were maintained at ~23&deg;C and 55%, respectively. The rats were pair-fed powdered diets. The electromyogram activities in soleus and EDL were elevated by cold exposure. The body weight and absolute soleus wet weight of the cold-exposed group were significantly less than controls at the end of experiment. The one-half relaxation time and contraction time of EDL were significantly longer in the cold-exposed group than in the control group. The rate of twitch tension development, normalized by the maximum twitch tension, in EDL of the cold-exposed group was less than in the control group. Further, the fatigue resistance of EDL, but not of soleus, in response to train stimulation at 10 Hz was improved by cold exposure. The plasma levels of thyroid hormones, 3,5,3&prime;-triiodothyronine and thyroxine, were significantly greater in cold-exposed group. Similar changes were also seen in the plasma catecholamine levels in the cold-exposed group (p > 0.05). It is suggested that long-term cold exposure causes a shift of the contractile properties of fast-twitch EDL muscle toward the slow-twitch type. The results also indicated that the characteristics of muscles responded more strongly to an increased activity level than to the elevation of plasma hormones.<br>