Effects of 20-Week Intermittent Cold-Water-Immersion on Phenotype and Myonuclei in Single Fibers of Rat Hindlimb Muscles

Lee, J.H.; Han, Eun Young; Kang, Myung Sun; Kawano, Fuminori; Kim, H.J.; Ohira, Yoshinobu; Kim, C.K.

doi:10.2170/jjphysiol.54.331

Cited by 8 publications

(12 citation statements)

References 26 publications

(50 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The percent distribution of fibers expressing type I, I ϩ IIa, or IIa MHC of the same soleus muscle as in the current study was identical for the control and cold-exposed groups [24]. However, a significant shift of the fiber phenotype expression from type IIb to IIa MHC was noted in EDL following cold exposure.…”

Section: Discussionsupporting

confidence: 68%

“…Suzuki et al [8] also reported that the soleus weight and the mean fiber cross-sectional area were significantly less in the cold-acclimated rats than in the control rats. The mean cross-sectional area of fibers expressing pure type I myosin heavy chain (MHC) of the same soleus muscle as in the current study was significantly less in the cold-exposed rats than in the control rats [24]. On the other hand, the weight of EDL relative to body weight was significantly increased after cold exposure.…”

Section: Discussionsupporting

confidence: 46%

“…The percent distributions of fibers expressing type IIa ϩ IIb (51 vs. 64%, pϽ0.05) and IIb (5 vs. 11%, pϾ0.05) MHC in EDL muscle of the cold-exposed rats were less than controls [24]. On the contrary, those of fibers expressing IIa MHC were elevated by cold exposure (42 vs. 24%, pϽ0.05), though the percent pure type I and I ϩ IIa MHC fibers remained constant.…”

Section: Discussionmentioning

confidence: 96%

“…On the other hand, the weight of EDL relative to body weight was significantly increased after cold exposure. A smaller crosssectional area was also noted in EDL fibers expressing the pure-type I MHC of the cold-exposed group ( pϾ0.05), though such phenomena were not seen in fibers expressing type IIa, IIa ϩ IIb, and IIb MHC [24]. However, the precise mechanism for such discrepant effects of cold exposure on muscle mass between soleus and EDL is unclear.…”

Section: Discussionmentioning

confidence: 99%

See 3 more Smart Citations

Effects of Long-Term Cold Exposure on Contractile Properties in Slow- and Fast-Twitch Muscles of Rats.

Nomura¹,

Kawano²,

Kang³

et al. 2002

JJP

View full text Add to dashboard Cite

Mechanical properties of skeletal muscles or motor performance in mammals [1][2][3][4][5][6][7][8][9], frogs [10,11], and fishes [12][13][14][15] are influenced by changes in environmental temperatures. For example, the maximum velocity of shortening and the maximum rate of tension development decreased at a low temperature in the soleus and extensor digitorum longus (EDL) muscles of rats [4]. Further, Faulkner et al. [1] reported that the maximum and sustained powers in mice EDL muscle were reduced by 40 and 62%, respectively, at 25°C compared to those at 35°C, though the isometric force remained constant. On the contrary, the maximum tetanic tension of rat soleus and EDL was increased steadily when the temperature was elevated from 6 to 30-38°C [3]. It is also reported that the average absolute force in skinned fibers of both soleus Japanese Journal of Physiology, 52, 85-93, 2002 Key words: cold exposure of rat, soleus, extensor digitorum longus, contractile properties, plasma hormones. Abstract: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 (nϭ10 each): cagecontrol and cold-exposed. The rats in the coldexposed group were immersed in shoulder-deep water (ϳ18°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 ϳ23°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, 3,5,3Ј-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 ( pϾ0.05). 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.

show abstract

Section: Discussionsupporting

confidence: 68%

Section: Discussionsupporting

confidence: 46%

Section: Discussionmentioning

confidence: 96%

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Effects of Long-Term Cold Exposure on Contractile Properties in Slow- and Fast-Twitch Muscles of Rats.

Nomura¹,

Kawano²,

Kang³

et al. 2002

JJP

View full text Add to dashboard Cite

show abstract

“…Recently, we have reported that Korean sea diving women who have been diving throughout their lives in cold water have high capillarity (Bae et al. 2003) comparable to that in animals chronically immersed in cold water (Lee et al. 2004).…”

mentioning

confidence: 99%