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51.
Dr. E. Carstens D. Klumpp M. Zimmermann 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1980,38(4):425-430
Summary Inhibition of spinal dorsal horn neuronal responses to noxious (50 °C) skin heating by stimulation of the midbrain periaqueductal gray (PAG) was quantitatively investigated in cats anesthetized with sodium pentobarbital and nitrous oxide. Systematic variation of the interval between onset of PAG stimulation (PAGS) and onset of noxious skin heating revealed that a marked reduction of spinal unit heat-evoked discharges occured immediately upon onset of PAGS, and ceased immediately at offset of PAGS with a post-stimulation excitatory rebound. Stimulation at sites in both ventral and dorsal PAG produced inhibition, the strength of which increased sometimes in a linear manner with increasing strength of PAGS. Thresholds for the generation of descending inhibition were higher in dorsal than ventral PAG. PAGS also inhibited spinal unit responses to non-noxious skin stimulation (brushing of hairs). Descending inhibition from PAG is considered as a possible mechanism for analgesia produced by stimulation of PAG and other brainstem structures.The work was supported by a grant from the Deutsche Forschungsgemeinschaft (Zi 110) 相似文献
52.
Krustrup P Söderlund K Mohr M González-Alonso J Bangsbo J 《Pflügers Archiv : European journal of physiology》2004,449(1):56-65
To investigate recruitment of slow-twitch (ST) and fast-twitch (FT) muscle fibres, as well as the involvement of the various quadriceps femoris muscle portions during repeated, intense, one-legged knee-extensor exercise, 12 healthy male subjects performed two 3-min exercise bouts at ~110% maximum thigh O2 consumption (EX1 and EX2) separated by 6 min rest. Single-fibre metabolites were determined in successive muscle biopsies obtained from the vastus lateralis muscle (n=6) and intra-muscular temperatures were continuously measured at six quadriceps muscle sites (n=6). Creatine phosphate (CP) had decreased (P<0.05) by 27, 73 and 88% in ST fibres and 25, 71 and 89% in FT fibres after 15 and 180 s of EX1 and after 180 s of EX2, respectively. CP was below resting mean–1 SD in 15, 46, 84 and 100% of the ST fibres and 9, 48, 85 and 100% of the FT fibres at rest, after 15 and 180 s of EX1 and after 180 s of EX2, respectively. A significant muscle temperature increase (Tm) occurred within 2–4 s at all quadriceps muscle sites. Tm varied less than 10% between sites during EX1, but was 23% higher (P<0.05) in the vastus lateralis than in the rectus femoris muscle during EX2. Tm in the vastus lateralis was 101 and 109% of the mean quadriceps value during EX1 and EX2, respectively. We conclude that both fibre types and all quadriceps muscle portions are recruited at the onset of intense knee-extensor exercise, that essentially all quadriceps muscle fibres are activated during repeated intense exercise and that metabolic measurements in the vastus lateralis muscle provide a good indication of the whole-quadriceps muscle metabolism during repeated, intense, one-legged knee-extensor exercise. 相似文献
53.
Wilson TE Johnson SC Petajan JH Davis SL Gappmaier E Luetkemeier MJ White AT 《European journal of applied physiology》2002,88(1-2):67-75
This study compared the effects of pre-exercise cooling with control water immersions on exercise-induced thermal loads derived
from steady-state submaximal exercise. Eight healthy male participants [mean (SEM) age 29 (1) years, maximal oxygen uptake
3.81 (0.74) l·min–1, and body surface area 1.85 (0.11) m2] took part in experiments that included 30 min of baseline data collection [ambient temperature 21.3 (0.2°C)], 30 min of
immersion in water to the level of the supra-iliac crest [water temperatures of 35.1 (0.3)°C for thermoneutral and 17.7 (0.5)°C
for precooled treatments], and 60 min of cycling exercise at 60% of maximal oxygen uptake. No significant differences were
noted during exercise in net mechanical efficiency, metabolic rate, O2 pulse, or ratings of perceived exertion between the two treatments. Precooling resulted in a significant negative body heat
storage during immersion and allowed greater heat storage during exercise. However, net body heat storage for the entire protocol
was no different between treatments. Cooling significantly lowered rectal, mean skin, and mean body temperatures as well as
more than doubling the exercise time until a 0.5°C rectal temperature increase was observed. The cooling trial significantly
delayed onset of sweating by 19.62 min and decreased sweat rate by 255 ml·h–1 compared to control. Thermal and sweat sensation scores were lower after the cooling treatment compared to control. These
data suggest that lower-body precooling is effective at decreasing body heat storage prior to exercise and decreases reliance
on heat dissipation mechanisms during exercise. Therefore, this unique, well-tolerated cooling treatment should have a broader
application than other precooling treatments.
Electronic Publication 相似文献
54.
A synthetic 10-kD heat shock protein (hsp10) from Mycobacterium tuberculosis modulates adjuvant arthritis 下载免费PDF全文
S. RAGNO V. R. WINROW P. MASCAGNI P. LUCIETTO F DI PIERRO C. J. MORRIS D. R. BLAKE 《Clinical and experimental immunology》1996,103(3):384-390
The heat shock protein, hsp10, is an abundant protein in Mycobacterium tuberculosis (Mtb), its nucleotide sequence encoding a protein of 99 amino acids with a molecular mass of 10±7kD. This sequence is phylogenetically conserved, being represented by the GroES homologue of Escherichia coli. Hsp 10 and GroES are members of the chaperonin 10 family of molecular chaperones, and GroES is necessary for the optimal activity of GroEL, a member of the chaperonin 60 family and the E coli homologue of mycobacterial hsp65. Since hsp65 has been implicated in both experimental and human rheumatoid arthritis, we aimed to assess the immunomodulatory effects of its co-chaperonin, hsp10, in experimental arthritis. Our results show that an aqueous solution of a mycobacterial hsp10 delayed the onset and severity of adjuvant-induced arthritis in rodents when administered after disease induction but before joint involvement occurred. This biological activity was specific for the hsp10 of Mtb, since neither GroES nor the rat homologue was effective. Using synthetic hsp10 fragments, the activity was localized to the N-terminal region of the molecule. Assessment of circulating antibody levels to mycobacterial hsp10 and hsp65 indicated that all arthritic rats had increased litres to both hsp10 and hsp65: hsp10-treated rats showed further elevation of this humoral response not only to hsp10 but also to hsp65 when compared with the untreated arthritic control. This is the first report of the immunomodulatory activity of mycobacterial hsp10 in experimental arthritis, and exhibits a potential role for this co-chaperonin in pathophysiological situations. 相似文献
55.
T. R. Tagirova V. I. Kapel'ko K. M. Karlyev 《Bulletin of experimental biology and medicine》1976,82(4):1458-1460
After preliminary adaptation of rats to heat (for 3 h daily at 35°C for 1 month) the amplitude of contractions of the isolated papillary muscles from the left ventricle at 28°C at high frequency was higher than in control animals. This difference persisted at 36°C and disappeared at 25°C. It is postulated that adaptation to heat leaves a definite structural imprint in heart muscle cells.Laboratory of Pathophysiology of the Heart, Institute of General Pathology and Pathological Physiology, Academy of Medical Sciences of the USSR, Moscow. Institute of Physiology and Experimental Pathology of the Arid Zone, Academy of Sciences of the Turkmenian USSR, Ashkhabad. (Presented by Academician of the Academy of Medical Sciences of the USSR A. M. Chernukh.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 10, pp. 1168–1170, October, 1976. 相似文献
56.
57.
Increased nasal air flow during exercise was examined as a possible heat loss avenue contributing to selective brain cooling in hyperthermic humans. On 2 separate days, eight subjects [mean (SE) age, 26.4 (1.2) years] exercised on a cycle ergometer in a warm room [28 (0.2)°C; 28 (5)% relative humidity] to induce a moderate level of hyperthermia. In one session the nostrils were physically dilatated [average dilatation 1.55 (0.17) times] and in the other they were not (control). Both sessions started with a 5-min resting period; then subjects pedaled at 60 W for 5 min, 100 W for 15 min, and 150 W for 20 min. During dilatation both tympanic temperature (T
ty) and forehead skin blood flow, estimated by laser doppler velocimetry, were significantly lower than during the control exercise of 150 W. Rates of increase of (T
ty) during the 100-W exercise were the same in both conditions; however, during the 150-W exercise with dilatated nostrils (T
ty) increased at a rate significantly lower than during control [1.1 (0.3)°C·h–1 vs 1.5 (0.4)°C·h–1]. The change in the rate of increase of T
ty between conditions was significantly correlated to the degree of nostril dilatation (r = –0.77, P = 0.02), suggesting that the lower (T
ty) observed was due to nostril dilatation. Facial skin temperature was not significantly different between sessions. The results suggest that the nasal cavity may act as a heat exchanger in selective brain cooling of exercising humans. 相似文献
58.
Previous studies have suggested that heat shock proteins (HSP) of Helicobacter pylori (H. pylori) are involved in the induction of autoimmunity mediated gastritis. In the present report, the cross-reactivity between H. pylori-related HSP60 and gastric epithelial cells was investigated by the indirect immunoperoxidase method using two monoclonal antibodies (mAb) against H. pylori-derived HSP60, H9 and H20. H9 is reactive with an epitope common to bacterial HSP60, while H20 is specific to H. pylori HSP60. A total of 70 paraffin-embedded gastric biopsy specimens were analyzed after heat-induced epitope retrieval. Both mAb were cross-reactive with the gastric epithelial cells, with a higher frequency seen for the H9-reactive epitope. The frequency of positive epithelial decoration was not significantly different between H. pylori-positive and H. pylori-negative gastric mucosae. A variety of epithelial and non-epithelial cells were immunostained with mAb H9, while mAb H20 was cross-reactive only with small intestinal epithelia. Reactivity was mainly located in the Golgi area and rarely in the cytoplasm. These results suggest a noteworthy pitfall in immunohistochemical interpretations of HSP60-associated autoimmune reactions in the gastric mucosa. 相似文献
59.
空肠弯曲菌HSP43诱导自身免疫机理──分子模拟和抗原优势 总被引:3,自引:0,他引:3
我们曾发现空肠弯曲菌43kD热休克蛋白(HSP43)能诱导小鼠产生自身免疫应答,本文则进一步分析了这种诱导作用的机理。二株针对HSP60保守区序列的单克隆抗体IIH9和ML-30不但能结合人及小鼠细胞中HSP60家族成员,而且也能结合HSP43,表明HSP43、人及小鼠HSP60三者均属同一家族成员,具有序列上的高度同源性。小鼠用空肠弯曲菌免疫后出现了针对10种菌体蛋白的抗体,其中最早被诱导的抗体是针对HSP43的,并且该种抗体在随后80d观察期间内保持了较高活性,表明HSP43是优势抗原。本文结果提示,HSP43较易被免疫系统识别而产生应答,通过和宿主HSP60高度序列同源性而可能呈现分子模拟,从而诱导自身免疫损伤。 相似文献
60.
S. Sakurada O. Shido N. Sugimoto K. Fujikake T. Nagasaka 《Pflügers Archiv : European journal of physiology》1994,429(2):291-293
Rats were subjected to an ambient temperature (Ta) of 33°C for ca. 5 h during the last half of the dark phase for 5, 14 or 28 consecutive days (heat-exposed rats, HE), while control rats were kept at a constant Ta of 24°C. After the heat exposure schedule, the levels of hypothalamic temperature (Thy) as an index of body core temperature in the HE were significantly lower than those of the controls for 2–4 h in the last half of the dark phase. The low levels of Thy persisted during the specific period for 1, 3 and 6 days after the end of the 5-, 14- and 28-day heat exposure schedules, respectively. These results confirm that, in rats subjected to daily heat exposure for ca. 5 h at a fixed time per day, their Thy falls during the period when the rats were previously exposed to heat, and suggest that the duration of the specific Thy change observed after completing the heat exposure schedule depends on the length of the heat exposure schedule. 相似文献